## W-834 01 Jul 13 **WRITE-IN CHANGES APPLIED**

**DATE: 20 NOV**  **2014 KC-10 Aircrew Training System** 

**Introduction to KC-10 Takeoff Performance**

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### LIST OF EFFECTIVE PAGES**KC-10 Aircrew Training System**

**Introduction to KC-10 Takeoff Performance**

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W831-TOC i 01 MAY 06 TABLE OF CONTENTS

1.0 INTRODUC TION ............................................................................................... 1-1

2.0 OBJECTIV ES .................................................................................................... 2-1

3.0 SPECIFICATION AND CERTIFICAT ION .......................................................... 3-1

4.0 TERMINOL OGY ................................................................................................ 4-1

5.0 BASIS FOR PERFORM ANCE CHART S ........................................................... 5-1

6.0 ENGINE-OUT TAKEO FF PROFIL E .................................................................. 6-1**KC-10 Aircrew Training System**

**Introduction to KC-10 Takeoff Performance**

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**Introduction to KC-10 Takeoff Performance**

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W831-01 1-1 01 JUL 13 1.0 INTRODUCTION

The KC-10 Mission Planning Performance training consists of two phases of instruction. The first phase is strictly academic with interactive computer-based training and workshops supplemented by workbooks. There are three CBT lessons, seven workbooks, and ten workshops for the Flight Engineers and five for the Pilots. Two workbooks, W831 Intr oduction to KC-10 Takeoff Performance and W834 Takeoff and Landing Data, are optional. In formation included in the two optional workbooks is thoroughly covered in the three CBT lessons. The

exercises included in the other five workbooks are optional. Questions and answers are provided in the workbooks. The second phase of tr aining is done during the simulator phase of training, w here you will apply proc edures taught in the academic phase. A TOLD card with different environmental, aircraft and runway conditions will be presented for completion for each simulator mission.

Your instructor will cover each card in detail.

1.1 SCOPE

The workbooks follow the Airline Trans portation Association (ATA) numerical code in the performance manual. AT A code assigns numbers to each system and subsystem that all users can use to identify pieces of equipment or systems to report malfunctions. These codes are found in t he front of the technical manuals. Workbooks One and Two mirror the CBT lessons and amplify the terminology, definitions, and procedures pr esented in those lessons. They also provide you with a "hard copy" of the material covered in computer-based training. Workbooks Three through Seven follow the sections of the performance manual from Climb through recovery and Flight/Fuel Planning. The Performance Manual, T.O. 1C-10(K)A-1-1 and T.O. 1C-10(K)A-1CL-1 are the primary

reference sources for the workbooks. Additional background information is presented from the following sources: Air Force Instruction (AFI) 11-202, Volume 3; AFI 11-230; AFI 11-2KC-10, Volume 3; Air Force Manual (AFMAN) 11-217, Volume 1, AFMAN 51-9; Federal Aviati on Administration Order 8260.3B, US Standard for Terminal Flight Instrument Procedures (TERPS); and KC-10 Flight Schedule/Computerized Flight/Fuel Plan.

1.2 INSTRUCTIONS

This workbook is optional.**KC-10 Aircrew Training System**

**Introduction to KC-10 Takeoff Performance**

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W831-01 1-2 01 JUL 13 1.3 BACKGROUND

When the Air Force decided to augment the KC-135 tank er force, a decision was made to purchase an existing airframe rather than design a new aircraft. Consideration was given to three existing commercial aircraft: the Boeing 747; Lockheed 1011; and the McDonnell Douglas DC-10-30 Freight er. DC-10 was

chosen.

It was quite a simple conversion. The aircraft was already equipped with three integral wing tanks and an auxiliary or extended range tank in the center fuselage. The forward and aft baggage co mpartments were converted to house

bladder fuel tanks. This became the Center Wing Tank. There were a few more superficial changes, but essentially the KC -10 is a converted DC-10-30 Freighter with an air refueling receptac le, boom and centerline drogue.

The DC-10 had been in commercial service fo r several years and was fully tested and certified by the FAA, so all perform ance data was certified to FAA standards. The test program for the acceptance of the KC-10 was not the same certification procedure all over again, but primarily a test of the modifications. The Air Force bought the complete package: Aircraft ; Flight Manuals; Checklists; and

Certification Procedures. T hat makes the KC-10 a "hybrid" animal. Since most military aircrews are used to Military Specifications and Terminology, it also makes aircraft performance a little more challenging.

Not only are different proc edures used to certify comm ercial aircraft, many times

the conditions and definitions used to de scribe those procedures differ. For instance, Ground Minimum Control Speed, or V MCG is defined the same way for both civilian and military aircraf t; however, the FAA certifies V MCG with a wet or icy runway with zero wind, while military aircraft take advantage of the effect of nose gear steering and apply crosswind component and RCR.

Most of the charts you will be using in computing KC-10 takeoff performance are compiled directly from the DC-10 chart ed test performance data. This data was

reformatted to MILSPEC tolerances w here possible. Where data was not available, actual flight te st data was used. In many cases, notes were added to

the charts to make the information fit the KC-10 performance criteria.

This lesson will introduce you to thos e items, differences in definitions and terminology, and their impact on KC-10 Takeoff Performance.**KC-10 Aircrew Training System**

**Introduction to KC-10 Takeoff Performance**

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W831-02 2-1 01 MAY 06 2.0 OBJECTIVES

Upon completion of this workbook you w ill be required to co mplete a CBT lesson followed by a multiple choice CBT test. You must accomplish the test with an 85%

accuracy.

A. Identify the differences between spec ifications used to certify performance for commercial and military aircraft.

B. Identify the definiti ons for the terminology a ssociated with performance

calculations.

C. Identify the criteria used to es tablish KC-10 perf ormance criteria.

D. Identify the events and parameters specific to the engine out takeoff profile.**KC-10 Aircrew Training System**

**Introduction to KC-10 Takeoff Performance**

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**Introduction to KC-10 Takeoff Performance**

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W831-03 3-1 01 APR 10 3.0 SPECIFICATION AND CERTIFICATION

3.1 RUNWAY REQUIRED FOR TAKEOFF-COMMERCIAL CERTIFICATION

Figure 3-1. Three Engine Takeoff.

All commercial aircraft must satisfy three field length criteria . The first, shown above (figure 3-1), is the distance required to accelerate on all engines to attain a height of 35 feet at the departure end of the runway, mu ltiplied by 115 percent.

You will hear this referred to as "Screen Height". All civilian Standard Instrument Departures take this into consideration.

Figure 3-2. Takeoff Continued.

Second: The distance required to accelera te on three engines to decision speed, lose a critical engine, and cont inue the takeoff to be at a height of 35 feet over the end of the runway (figure 3-2). The important thing to remember here is the height at the end of the runway. ALL ENGINE TAKEOFF DISTANCE TO

CFL 35 FT

X 115% V LOF

ALL ENGINE ACCELERATION 35 FT V 1

V LOF

TWO ENGINE ACCELERATION**KC-10 Aircrew Training System**

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W831-03 3-2 01 APR 10 Figure 3-3. Takeoff Aborted.

Third: The distance required to accelerate on three engines to critical engine failure speed, lose an outboard engine, and stop in the remaining runway distance (figure 3-3). ALL ENGINE ACCELERATION STOP DISTANCE V 1**KC-10 Aircrew Training System**

**Introduction to KC-10 Takeoff Performance**

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W831-03 3-3 01 APR 10 3.2 RUNWAY REQUIRED FOR TAKEOFF-MILSPEC CERTIFICATION

Now look at the runway requi rement for military aircraft.

Figure 3-4. Takeoff Continued.

Military Specifications or MILSPECS specify two criteria for the limiting runway. The first is distance required to accelera te on three engines to decision speed, lose a critical engine, and continue the takeoff and liftoff at the end of the

runway (figure 3-4).

Note: While the commercial version places t he aircraft at a height of 35 feet over the departure end of the runway, the military version will be at zero feet

.

Figure 3-5. Takeoff Aborted.

And secondly, the distance required to acce lerate on three engines to decision speed, and stop in the remaining runway is considered as a criteria. The runway

available in both cases bei ng Critical Field Length.

Complete the following ex ercise before continuing. ALL ENGINE ACCELERATION V 1

TWO ENGINE

ACCELERATE/STOP DISTANCE

CFL V R V LOF

ACCELERATION

ALL ENGINE ACCELERATION V 1

STOP DISTANCE**KC-10 Aircrew Training System**

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W831-03 3-5 01 APR 10 3.3 LESSON EXERCISE

1. The KC-10 is a variant of the ___________________________ __ aircraft.

2. Terminology and definitions of terms are the two major differences between ___________________ ___________________ certification and

_________________________ ce rtification.

3. Where possible, the DC- 10 flight test data was us ed in the KC-10. This was often accomplished by adding ____________________ to the charts.

4. One of the major differences in the takeoff distance certification procedures between FAA and Military specifications is that the civilian version must achieve an engine-out altitude of ______ ________ feet at the end of the runway while the Milit ary version is ______________ feet.

5. This height at the end of the runway is sometimes referred to as ____________ height, and is incorporated into commercial standard instrument departures.

6. Military certification procedures require that the aircraft be able to accelerate to ______________ speed on __________ engines, lose a

_________________________, and either ____________ the takeoff or _____________ in the ___________ runway.

7. The distance required to accomplish the events in question 6 is called

________________________ __________.**KC-10 Aircrew Training System**

**Introduction to KC-10 Takeoff Performance**

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W831-03 3-6 01 APR 10 3.4 LESSON EXER CISE ANSWER KEY

1. DC-10-30 Freighter 2. Military/Commercial

3. Notes

4. 35/zero

5. Screen 6. Decision/all/critical engine/continue/stop/remaining 7. Critical Field Length**KC-10 Aircrew Training System**

**Introduction to KC-10 Takeoff Performance**

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W831-04 4-1 01 JUL 13 4.0 TERMINOLOGY

4.1 GROUND DISTANCE REQUIREMENTS

Figure 4-1. Critical Field Length (CFL).

Critical Field Length (CFL) is defined as t he distance required to accelerate from brake release to Critical Engine Failure Speed (V CEF ) with all engine s operating at takeoff power; lose an engine and either c ontinue the takeoff on two engines or stop in the same distance (figure 4-1). The KC-10 performance charts optimize the flap setting in an attempt to make Critical Field Lengt h equal to Runway Available. If performance calculations ar e followed accurately, the Critical Field Length will always be equal to or less than Runway Available.

Figure 4-2. Lineup Distance.

Lineup distance is defined as t he distance required to taxi on to the runway and align

the aircraft for takeoff. This distance for the KC-10 is 300 f eet (figure 4-2). This is a

nominal distance under ideal conditions. For unusual runway entry requirements or 180-degree turns on the runway, always use the actual distance required.**KC-10 Aircrew Training System**

**Introduction to KC-10 Takeoff Performance**

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W831-04 4-2 01 JUL 13 Figure 4-3. Standard Stressed Overrun.

Stressed Overrun is defined as a paved surf ace that will support aircraft that are
authorized to takeoff or land at that airport. The overru n is depicted as light shaded areas at the end of each runway. The lengt h and width are provided. This is the standard overrun at most airpor ts. Figure 4-3 shows the Ai rfield Diagram for Travis AFB, CA. Notice that runways 03R and 21L have the standard overrun distances. OVERRUN

1000’ X 300’

OVERRUN

1000’ X 300’**KC-10 Aircrew Training System**

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W831-04 4-3 01 JUL 13 Figure 4-4. Non-Standard Stressed Overrun. OVERRUN

700’ X 200’

NO

OVERRUN**KC-10 Aircrew Training System**

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W831-04 4-4 01 JUL 13 Figure 4-4 is the Airfield Diagram of Norfolk Naval Air Station, Chambers Field, Virginia. Notice that Runway 28 has a paved overrun of 700 feet, and Runway 10

has no overrun. The minimu m allowable runway for KC- 10 operation is 7,000 feet, unless waived by the command authority. For mission accomplishment, if takeoff

end overruns are available and stressed or authorized for normal operations, they may be used to increase the ru nway available for takeoff. Departure end overruns (if stressed and authorized) may also be used for landing if needed. Consult with HQ AMC/A37V for suitability guidance.

4.2 SPEEDS USED IN THE TAKEOFF SEQUENCE

Figure 4-5. Ground Minimum Control Speed (V MCG ).

Ground Minimum Control Speed , or V MCG , is defined as the minimum airspeed at which the airplane, while on the ground, c an experience a wing engine failure and maintain directional control, with takeoff thrust set on the remaining engines, without exceeding a lateral deviation of 25 feet from runway cent erline (figure 4-5). During reduced thrust takeoffs, power on remain ing engines may be in creased to takeoff thrust only after reaching 135 knots (worst case wet/icy V MCG / V R MIN ). The KC-10

charted V MCG is the FAA recognized version, us ing zero crosswind and a wet/icy runway. The KC-10 chart has a note added to allow 10 knots to be subtracted from

this charted value to account for the benef it of nose wheel steering when the RCR is 10 or greater. Data are show n for RCR values less than 10, V MCG correction if RCR greater than or equal to 10. If RCR is greater than or eq ual to 10 and no RSC exists and crosswind component less than or equal to 10: subtract 10 knots. RCR < 10 - NG STEERING NOT EFFECTIVE

FULL RUDDER

INOPERATIVE 25'

V >

_ DEFLECTION

ENGINE RCR 10 - NG STEERING EFFECTIVE

V MCG**KC-10 Aircrew Training System**

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W831-04 4-5 01 JUL 13 Figure 4-6. Decision Speed (V 1 ).

Decision Speed , or V 1 , is defined as that speed used to determine whether to continue the takeoff or abort following an engine fa ilure. It is the higher of Critical Engine Failure Speed (VCEF) or Minimu m Ground Control Speed (VMCG), not to exceed Maximum Braking S peed (VMBE). Decision S peed is normally associated with an engine failure at or near V 1 . Decision Speed is us ually Critical Engine Failure Speed and may not be lower than Ground Minimum Control Speed or higher than Maximum Braking Speed. Th e takeoff is aborted before V 1 if a serious emergency/loss of thrust occurs because the takeoff may not be achieved in the remaining runway. If an emergency occurs after V 1 is reached, the takeoff is committed because there may not be enough runw ay remaining to stop (figure 4-6). Hence the name, “Decision Speed". See Section 5 of this workbook for an explanation of Critical Field Le ngth verses Runway Available.**KC-10 Aircrew Training System**

**Introduction to KC-10 Takeoff Performance**

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W831-04 4-6 01 JUL 13 Figure 4-7. Minimum Unstick Speed (V MU ).

Minimum Unstick Speed , or V MU , is defined as "that speed at which an aircraft may be lifted off without demonstrating unstable fl ying characteristics". There are no charts in the Performance Manual for this speed; however, speeds such as 1.0g Stall Speed, Rotate S peed, and Liftoff Speed are based directly on V MU . Take a look at Figure 4-8.

Figure 4-8. Positive A ngle of Incidence.

Many aircraft, such as the C-5, are designed with a positive angle of incidence between the wing and fuselage, which g enerates lift (and dr ag) throughout the takeoff roll (figure 4-8). W hen the speed is sufficient to generate the required lift, the aircraft automatically lifts off. This in creased drag however, results in a longer takeoff ground roll. V MU



### e a

V V

e theta

a alpha = Relative Wind

= Pitch Attitude

= Angle of Incidence**KC-10 Aircrew Training System**

**Introduction to KC-10 Takeoff Performance**

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W831-04 4-7 01 JUL 13 Figure 4-9. Neutral Angle of Incidence.

The KC-10 is designed with an almost ne utral angle of incidence (figure 4-9). It generates very little lift (or drag) during the takeoff ground roll. V

e theta

a alpha

e

a

V = Relative Wind

= Pitch Attitude

= Angle of Incidence

a**KC-10 Aircrew Training System**

**Introduction to KC-10 Takeoff Performance**

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W831-04 4-8 01 JUL 13 Figure 4-10. 1.0g Stall Speed.

Due to the nearly neutral angle of incidence , the aircraft must be deliberately and forcibly rotated from a three point attit ude to achieve an angle of attack that will produce enough lift for flight. At some poi nt during the rotate sequence, the lift produced by the wings will equal the weight of the aircraft (figure 4-10). This is the definition of 1.0g Stal l Speed and is the basis for a ll takeoff speeds from rotate through V 2 . This speed is one of two chart ed stall speeds in the Performance Manual. It is a "Power On" stall speed and is considerably higher than the "Minimum Stall Speed.” > a LIFT

WEIGHT**KC-10 Aircrew Training System**

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W831-04 4-9 01 JUL 13 Figure 4-11. Air Minimum Control Speed (V MCA ).

Air Minimum Control Speed , or V MCA , is the minimum speed at which an aircraft while airborne, can experience a wing engi ne failure maintain directional control using full rudder deflection and not more th an five degrees of bank angle (figure 4- 11). This speed is not limiting on the KC -10 with a fully operational rudder system. YAWING MOMENT COEFFICIENT

AIR MINIMUM

FROM MAXIMUM USABLE

INDICATED AIRSPEED 5 DEGREES OF BANK

RUDDER DEFLECTION FROM ASYMMETRICAL THRUST

CONTROL SPEED

YAWING MOMENT COEFFICIENT**KC-10 Aircrew Training System**

**Introduction to KC-10 Takeoff Performance**

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W831-04 4-10 01 JUL 13 Figure 4-12. Minimum Stall Speed (V S ).

Minimum Stall Speed , or V S , is the minimum speed at which an aircraft will cease to produce enough lift to sustain flight. This occurs during a period of the stall where the lift generated is less than the weight of the aircraft. This is referred as a "Power Off" speed. That is: The speed is reduced in increments of one knot per second while maintaining altitude. The speed at which the altitude can no longer be
maintained is the Minimum St all Speed (figure 4-12). It is the basis for all approach and landing speeds.

Figure 4-13. Rotate Speed (V R ).

Rotate Speed , or V R , is that speed at which the KC-10 must be deliberately and forcibly rotated from a three point attitude to pitch angle that will produce enough lift to sustain flight. This speed is based on 1.0g Stall Speed. The charts are based on
a four second time frame for this event. Th is time equates to approximately 800 to 1,200 feet of runway required fr om start of the rotate sequenc e to liftoff (figure 4-13).
Charted V R has been increased by approximately 8 knots to provide adequate boom
clearance at rotate. SPEED IS REDU CED AT 1 KN OT PER SEC ON D STALL 1.5 V S 1.4 V S 1.15 V S 1.05 V S 1.0 V S

AP PRO X 1,000' V R**KC-10 Aircrew Training System**

**Introduction to KC-10 Takeoff Performance**

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W831-04 4-11 01 JUL 13 Figure 4-14. Liftoff Speed (V LOF ).

Liftoff Speed , or V LOF , is the speed at which the ai rcraft becomes airborne. For planning purposes in the KC-10, this occurs at the end of the runway at a predetermined pitch angle what will allow continued acceleration to Climbout Speed, or V 2 . This speed was increased the same increment as Rotate.

Figure 4-15. Climbout Speed (V 2 ).

Climbout Speed , or V 2 , is defined by the FAA as 11 5 percent of t he charted 1.0g Stall Speed. Si nce Rotate and V 2 have both been increased by 8 knots, the KC-10 Climbout Speed, or V 2 , always exceeds the FAA minimu m requirement. This speed is achieved at a height of 50 feet abov e the ground with the gear handle in the up position, and with the flaps and slats in the takeoff configuration (figure 4-15). V LOF

V LOF

50' V 2**KC-10 Aircrew Training System**

**Introduction to KC-10 Takeoff Performance**

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W831-04 4-12 01 JUL 13 Figure 4-16. Climbout Speed 2 or 3 Engine.

The minimum Climbout Speed for the KC-10 is based on V 2 for 2 engine climb and

V 2 plus 10 Knots for 3 Engine climb (figure 4-16). These speeds were chosen to provide the maximum amount of height for the minimum horizontal distance, or simply, the best angle of climb. Since th e takeoff data is based on the runway available and required climb gradient, this speed will assure the minimum climb gradient or the gradient required by an obstacle will be achi eved with an engine inoperative. Now look at so me climb gradient criteria. V LOF

50' V 2

2 ENGINE CLIMB

V LOF

50' V 2 + 10

3 ENGINE CLIMB**KC-10 Aircrew Training System**

**Introduction to KC-10 Takeoff Performance**

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W831-04 4-13 01 JUL 13 4.3 CLIMB GRADIENT

Figure 4-17. Climb Gradient.

Climb Gradient is defined as the net vertical height divided by the horizontal distance (figure 4-17). You have more than likely us ed this formula to determine either height at a given distance, or distance at a gi ven height. You recall that the minimum allowable climb gradient for the KC-10 is 2.5%. Using that formula, at one nautical mile, the KC-10 should be at 152 feet.

152' X 100 = 2.5% 6080 X 2.5% = 152
6080'

OR

40:1

RATIO

Figure 4-18. Gradient = Height/Distance (G=H/D).

First, using the height-divided-by-distance linear equation, you ca n determine that a height of 152 feet in one naut ical mile will require a 2. 5% gradient; or 152 divided by 6,080 feet will yiel d a gradient of 2.5% (f igure 4-18). However, take a look at a KC10 climb gradient chart and see why this will not work (figure 4-19). GRADIENT = H (HEIGHT)

GRADIENT % H

D D (DISTANCE)**KC-10 Aircrew Training System**

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W831-04 4-14 01 JUL 13 Figure 4-19. Gross Climb Gradient.

Figure 4-19 is an extract of sheet 3 of the Climbout Flight Path series in the

Performance Manual. Enter this chart with 6,080 feet and apply the most limiting flap setting correction. Intersect the 2.5% gradient line, and r ead the height at the left. Notice the height is well below 152 feet. This is because the KC-10 climb gradient charts are based on a "gro ss" gradient and not a "net" gradient. 6,080 ′ 110 ′**KC-10 Aircrew Training System**

**Introduction to KC-10 Takeoff Performance**

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W831-04 4-15 01 JUL 13 Figure 4-20. Net Climb Gradient.

Now look at the actual or "net" gradient required to ac hieve 152 feet in one nautical mile (figure 4-20). Again, enter the chart with 6,080 feet and the most limiting flap

correction and now intersect the desired height of 152 feet . Note that the gross gradient required to achieve the required height is 3. 5% (based on no tailwind). The standard linear equation cannot, under any circumstances, be used to

152 ′

6080’**KC-10 Aircrew Training System**

**Introduction to KC-10 Takeoff Performance**

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W831-04 4-16 01 JUL 13 compute KC-10 climb performance . The only acceptable method is to enter the charts with the obstacle height and distanc e from the departure end of the runway and use the resulting charted gross gradi ent to compute all obstacle clearance

calculations.

Now take look at the KC-10 Climbout Flig ht Path (One Engine Inoperative) and

actual criteria for Obstacle Clearance.

Figure 4-21. Engine Out Climb Segments.

For the purposes of this discussion, the KC-10 Obstacle Clearance Criteria is
divided into four areas of consideration: This will cover only the Engine Out
Profile

.
1. FIRST SEGMENT
2. SECOND SEGMENT
3. TRANSITION SEGMENT
4. FINAL CLIMB SEGMENT

1. The first segment begins just after li ftoff and continues until the landing gear is retracted. The speed will vary between V LOF and V 2 at 50 feet.

2. The second segment starts at the point the gear is fully retracted and continues until the aircraft reaches Pressure Height for Acceleration. The minimum speed for this segment is V 2

.

3. The transition segment is the portion of the flight path during which the airplane is accelerated in level flight to the V SR

. Flaps and slats are retracted as the recommended flap and slat retr action speeds are reached.

4. In the final segment, t he airplane climbs at V SR using MCT power with the gear, flaps, and slats retracted.**KC-10 Aircrew Training System**

**Introduction to KC-10 Takeoff Performance**

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W831-04 4-17 01 JUL 13 Before discussing the KC-10 Climb Segments in detail, take a look at the basis for the climb profiles, as far as the FAA is concerned.

The following paragraphs are ex tracted from FAA Depart ure Order 8260.3B, Volume 4, Departure Procedure Construction.

GENERAL. IFR departure procedures may be designed and published for all runways authorized by the approving authority. For civil procedures, runway/taxiway separ ations, and airport obstacle free zones (OFZ) must meet the standards in Advisory Circular (AC) 150/5300-13, Airport Desi gn, or appropriate military directives for military procedures for specified departure visibility

minimums.

Departure Obstacle Clearance Surface (OCS) Application.

The OCS is an inclined surface associated with a defined area

for obstacle evaluation. The OCS slope is 40:1. This equates to 152 ft/NM which is expressed as a 2.5% linear climb gradient (6080 ÷ 152 = 40). The minimu m climb gradient of 200 ft/NM also provides for an additional Required Obstacle Clearance (ROC) of 48 feet (152 + 48 = 200) . The OCS begins at the DER

at DER elevation. EXC EPTION: Adjust the origin height up to 35 feet above DER as necessary to clear existing obstacles. Evaluate proposed obstacles assu ming the OCS origin is at

DER elevation.

Diverse Departures. A Diverse Departure is a departure without restrictions to the route of flight. At many airports , a prescribed departure route is not required for ATC purposes or as the only suitable route to avoid obstacles. In spite of this, there may be obstacles in the vicinity of the airport that s hould be considered in determining that restrictions to departures are to be prescribed in a given sector(s). The areas and surfac es described herein are to be used to identify such obstacl es. Areas are described by bearings and distance from Departu re Reference Point (DRP).

NOTE: Air Force Instruction dictate specific guidance and restrictions concerning Diverse Departures.

This directive has much more extensive information on Diverse Departures, but for this discussion you need only concern yourself with the following areas; Initial Climb Area, Diverse “A” area, and Diverse “B” area.**KC-10 Aircrew Training System**

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W831-04 4-18 01 JUL 13 Figure 4-22. Initial Climb Area.

INITIAL CLIMB AREA (ICA).

The ICA is an area centered on the runway centerline extended used to evaluate obstacle clearance during the climb to 400 feet above Departure End of Runway (DER) at a minimum climb gradient of 200 ft/NM.

ICA Baseline (ICAB). The ICAB is a line extending perpendicular to the runway centerline ± 500 at DER. It is the origin of the ICA.

ICA End-line (ICAE).

The ICAE is a line at the end of the IC A perpendicular to the runway centerline extended. The splay of 15° and lengt h of the ICA determine its width.

Area: Length. The ICA length is normally 2 NM, meas ured from the ICAB to the ICAE along runway centerline extended. It may be less t han 2 NM in length for early turns by publishing a climb gradient, or a combination of climb gradi ent and reduction in Take Off Runway Available (TORA). The ICA ma y be extended beyond 2 NM to maximum length of 10 NM. A specified altitude (typically 400' above DER) or the interception of Positive Course Guidance (PCG) route must identify the ICAE.

Width. The ICA origin is 1,000 feet (± 500 perpendicular to runway centerline) wide at the DER. The area splays outward at a rate of 15° relative to the departure course (normally runway centerline).

OCS. The OCS originates at the ICAB, normall y at DER elevation. Apply the OCS by measuring the shortest distance from the ICAB to the obstacle.**KC-10 Aircrew Training System**

**Introduction to KC-10 Takeoff Performance**

CH 5

W831-04 4-19 01 JUL 13 Figure 4-23. Diverse ”A” and “B” Areas

GENERAL.

Evaluate diverse “A” and “B” areas to a distance of 25 NM for non-mountainous

areas and 46 NM for mountaino us areas. If obstacles do not penetrate the OCS, unrestricted diverse departure may be authorized; publis h standard takeoff

minimums.

Diverse "A" Area.

All areas on the DER side of the DRL. Calculate the height of the OCS at any given location in the diverse "A" area by measuri ng the distance from the obstacle to the closest point on the center line of the runway between the DRP and DER, or the closest point on ICA boundary li nes as appropriate. The be ginning OCS elevation is equal to the MSL elevation of the ICAE.

Diverse "B" Area. All areas on the Starting Elevation of Runway (SER) side of the DRL. Evaluate obstacles in the Diverse "B" area by measur ing the distance in feet from the obstacle

to the DRP.

Note: Additional information can be found in Air Force Instructions (AFI) and Air Force Manuals (AFMAN), e.g. AFI 11-2KC-10 Vol. 3, AFI 11-202 Vol. 3, AFI 11-230, and AFMAN 11-217, Vol. 1. Such inform ation can be referenced; instrument departure criteria, obstacle clearance requi rements, climb gradients, minimum climb rates, all engine criteria, one engine i noperative criteria, Special Departure Procedures, diverse departures, departure routes, standard instrument departures (SIDs), etc.**KC-10 Aircrew Training System**

**Introduction to KC-10 Takeoff Performance**

CH 5

W831-04 4-20 01 JUL 13 Figure 4-25. First Climb Segment.

As stated earlier, for the pur poses of this discussion, t he engine-out climbout flight path is broken down into four segments. This is the first segment. A climbout flight path is plotted from liftoff to the start of the pressure height for acceleration. The minimum plot is based on a 2.5% gradient with two engines at takeoff power, V 2 set by 50 feet AGL, and flaps and slats in the takeoff configuration. Any object which penetrates this plane will be cleared by r equiring a higher climb gradient or increasing the distance to the obstacle by reducing the runway available.HEIGHT

AT 50 FEET

GEAR HANDLE UP AT V 2 T.0. FLAP AND SLATS EXTENDED

10 MILES

DISTANCE 1500 ’**KC-10 Aircrew Training System**

**Introduction to KC-10 Takeoff Performance**

CH 5

W831-04 4-21 01 JUL 13 Figure 4-26. Second Climb Segment.

The second segment starts at the point the gear is fully retracted and continues until the aircraft reaches Pressure Height for Acceleration. The mi nimum speed for this segment is V 2

.**KC-10 Aircrew Training System**

**Introduction to KC-10 Takeoff Performance**

CH 5

W831-04 4-22 01 JUL 13 Figure 4-27. Transition Segment.

This segment begins approximately 10 nautical miles from liftoff and continues for another 10 miles (figure 4-27). This altitude is 1,500 feet for standard day temperatures, and is adjusted up or down as required. At this point, the aircraft is

leveled off and allowed to accelerate to a point where the flaps and slats are

retracted. The aircraft is flown in the clean configuration at slat retract speed. No object shall penetrate this pressure heigh t for acceleration. If an obstacle exists within this envelope, the obstacle heigh t becomes the pressure height for

acceleration.HEIGHT

DISTANCE**KC-10 Aircrew Training System**

**Introduction to KC-10 Takeoff Performance**

CH 5

W831-04 4-23 01 JUL 13 Figure 4-28. Final Climb Segment.

The final segment begins at the end of the transition segment with the aircraft in a clean configuration at slat retract speed (f igure 4-28). The airplane climbs at V SR using MCT power with the gear, flaps, and slats retracted. The purpose of the transition segment was to set up this final climb segment in order to clear distant
obstacles. This schedule and f light path is a procedure that will assure that distant
obstacles will be cleared.

Please complete the following exercise before continuing.**KC-10 Aircrew Training System**

**Introduction to KC-10 Takeoff Performance**

CH 5

W831-04 4-24 01 JUL 13 4.4 LESSON EXERCISE

1. Since the KC-10 performance charts optimize the flaps to the length of the runway, the critical field length will always be equa l to or less than the _______________

__________________.

2. The lineup distance fo r the KC-10 is ___________ feet.

3. You are planning a takeoff on a runw ay that is 9,700 feet long with 500 feet of paved overrun. What is t he runway available for takeoff? Ans.___________________.

4. V MCG is the speed at whic h directional control can be achieved using

full rudder deflection and not deviate more than __________ feet from runway centerline.

5. When the RCR is 10 or great er, subtract ___________ knots from

charted V MCG to account for the effect of

__________________ _______________.

6. Decision speed, or V 1 , is usually V CEF but not lower than ___________ or higher than _______________.

7. The speed at which an aircraft may be lifted off without displaying unstable flying characteristics is called

________________________ _______ , and is the basis for 1.0g Stall Speed.

8. All takeoff airspeeds are bas ed on Power On _______________ stall speed.

9. The KC-10 is not V MCA limited as long as all

________________________ are operational.

10. Minimum Stall Speed is a much lower speed than 1.0g Stall Speed. It

is used as a basis for _____________ and _______ ___ speeds.

11. A ___________ second time frame is allocated to rotate the aircraft from a three-point attitude to a pitch angle for takeoff.

12. All takeoff speeds have been increased by __________ knots over charted test data to allow for adequate

__________________ ____________.

13. V 2 , or Climbout Speed, should be ac hieved at a height of _________

feet above the takeoff elevation.**KC-10 Aircrew Training System**

**Introduction to KC-10 Takeoff Performance**

CH 5

W831-04 4-25 01 JUL 13 14. Climbout speeds were chosen to approximate the best ___________

of climb in order to achieve th e highest ___________ distance for the

minimum horizontal distance traveled.

15. The minimum climb gradient r equired for the KC-10 is _________ percent.

16. This gradient is a __________ gradient and not a net gradient; therefore, the convent ional gradient formula cannot be used to determine a given height for a given distance.

17. The Obstacle Clearance Surfac e slope is a ________ to ________

ratio.

18. This height equates to ________ feet per nautical mile or a climb gradient of ______ percent.

19. Any obstacle that lies within ___ _______ degrees of the Initial Climb Area (ICA), and penetrates the obstacle clearance surface (OCS) shall be identified on the departure.

20 The standard geometric pressure height for acceleration is _______, and is adjusted up or down for non standard ________________.

21. After leveling off at the pressure height for accelerati on, the aircraft is

allowed to accelerate to

_________________________ ___ where the

____ _________________ are retracted; then to

________________________ __________ where t he __________ are

retracted. The aircraft is now climbed at

________________________ _____ until all obstacles are cleared or

the minimum altitude for enr oute operations is reached.

22. The Pressure Height for Accelerati on level off and clean up is the only way to insure that ___________ obstacles are cleared.**KC-10 Aircrew Training System**

**Introduction to KC-10 Takeoff Performance**

CH 5

W831-04 4-26 01 JUL 13 4.5 LESSON EXER CISE ANSWER KEY

1. Runway Available

2. 300 3. 9,400

4. 25 5. 10/nose wheel steering

6. V MCG /V MBE 7. Minimum Unstick Speed 8. 1.0g 9. Rudder Systems 10. Approach/Landing

11. 4

12. 8/boom clearance

13. 50 14. angle/vertical

15. 2.5 16. gross

17. 40/1

18. 152/2.5

19. 15 20. 1,500 feet/temperatures 21. flap retract speed/flaps/slat retr act speed/slats/slat retract speed

22. distant**KC-10 Aircrew Training System**

**Introduction to KC-10 Takeoff Performance**

CH 5

W831-05 5-1 01 JUL 13 5.0 BASIS FOR PERFORMANCE CHARTS

Up to this point the discussion has bee n on concept, methodology, definitions and procedure. Now you will co ver the criteria used to establish the basis for the charted data in the performance manual. You will look at four areas affecting performance calculations. First you will cover engine data a nd the relationship between thrust and temperatur e, pressure altitude, and speed. Next you will define the environmental envelope; establis h takeoff thrust requirements; and finally; cover the methods for determi ning reduced power takeoff criteria.

5.1 ENGINE DATA

1234 5678 9 0 32 34 36 38 40 42 44 46 48 50 52 54 56

ALTITUDE, 1000 FT -50M

-45A

-50C

-50A

-6D1

-6D -45B

IDEAL THRUST, TAKEOFF THRUST VARIATION WITH ALTITUDE

1000 LB AT FLAT RATE TEMPERATURE

-CF6-50C2*

*DESIGN TEST DATA

Figure 5-1. Constant Temp erature Varied Altitude.

The KC-10 is equipped with three General Electric CF6-50C2 engines. This engine is a variant of the basic 50 series t hat has been in service for many years. Figure 5-1 shows the relationship of thrust with altitude at a constant temperature.

Note that the thrust decreases as a functi on of altitude if the temperature remains constant. All performance charts in t he performance manual make use of this

linear decrease.**KC-10 Aircrew Training System**

**Introduction to KC-10 Takeoff Performance**

CH 5

W831-05 5-2 01 JUL 13 ENGINE CF6-50C2

SEA LEVEL STATIC, UNINSTALLED

TAKEOFF IDEAL THRUST (LB) REAL THRUST (LB) SFC (IDEAL) * 52,500 51,800

.394

MAX CONTINUOUS REAL THRUST (LB)

SFC 46,300

.385

35,000 FT M=0.85, UNINSTALLED

MAX CLIMB REAL THRUST (LB)

SFC 11,500

.664

MAX CRUISE REAL THRUST (LB)

SFC 10,800

.654

* DESIGN TEST DATA

Figure 5-2. Constant Alti tude Temperature Varies.

The thrust also varies as a function of te mperature at a constant altitude. One of the characteristics of a flat rated engine is that it will pr oduce a predictable,

constant amount of thrust ov er a wide range of environm ental conditions. Figure 5-2 shows the thrust and specific fuel consumption for various power settings. Temperature is the second leg of the power equation.**KC-10 Aircrew Training System**

**Introduction to KC-10 Takeoff Performance**

CH 5

W831-05 5-3 01 JUL 13 Figure 5-3. Constant Altitude Cons tant Temperature Velocity Increase.

This figure shows the relationship betw een increased velocity, or airspeed and

thrust. Note that the available thrust decreases as the MACH increases. This is a very small variant during the takeoff s equence; however, it becomes a player at climb and cruise airspeeds. All performanc e charts are built around these three factors: Temperature, Altitude and Speed. TAKEOFF THRUST VARIATION

WITH MACH NO.

REAL NOZZLE

THRUST

1000 LB

MACH NO

. CF6-6D CF6-6D1 CF6-45A/B CF6-50M

CF6-50E

CF6-50C

CF6-50A**KC-10 Aircrew Training System**

**Introduction to KC-10 Takeoff Performance**

CH 5

W831-05 5-4 01 JUL 13 Figure 5-4. Thrust VS. N 1 RPM.

As you have seen, the thrust available for a given set of conditions is built into the performance charts. Unlike many ot her aircraft, you do not use a "Thrust Factor", "Takeoff Factor" or for that matte r, any other factor except temperature and pressure altitude to determine performance calculations. The N 1 RPM is the

sole measure of thrust in the KC-10. In the takeoff range, 1 percent N 1 equals about 1.8 percent of the av ailable thrust for a given set of conditions.

Now take a look at the performance factors of a "Flat Rated Engine". RPM**KC-10 Aircrew Training System**

**Introduction to KC-10 Takeoff Performance**

CH 5

W831-05 5-5 01 JUL 13 5.2 ENVIRONMENTAL ENVELOPE

BREAK POINT: FLAT-RATED THRUST

NOTE:

TEMPERATURE

MAXIMUM CERTIFIED TEMPERATURE THRUST N1 THERE IS A SIMILAR

LINE FOR EACH

ALTITUDE UP TO THE

MAXIMUM CERTIFIED

ALTITUDE REDUCED THRUST

PERMITTED

Figure 5-5. Flat Rated Engine.

The CF6-50 engine is flat rated. It will produ ce a constant amount of thrust at a given altitude as a function of temperature. In figure 5-5 you see one altitude line as would be depicted on a performance char t or the environmental envelope. There is a line from the bottom of the envelope to the maximum certified altitude. From the minimum temperature to the break point, the thrust will remain constant. At the break point the thrust will decrease as a function of temperature until the maximum certified temperature is reached.

14

12

10

8

6

4

2

0

-1

-54 -50 -40 -30 -20 -10 0 10 20 30 40 50 60 STANDARD DAY

BREAK POINT TEMPERATURE

Figure 5-6. Break Point VS. Altitude.

Figure 5-6 adds the remaining lines with the break point temperature for each

line. Note that the break point remains the same from -1,000 feet to an altitude of 2,400 feet. From here the temperatur e decreases until it r eaches 5,000 feet. It now remains the same up to the maxi mum certified altitude of 14,000 feet.**KC-10 Aircrew Training System**

**Introduction to KC-10 Takeoff Performance**

CH 5

W831-05 5-6 01 JUL 13 Figure 5-7. Standard Day + 40.

Figure 5-7 shows the standard day pl us 40 degree line plotted against the standard day temperature. It starts at the maxi mum allowable ambient temperature of 50 degrees Celsius, remains constant until 2,400 feet. It then parallels the standard day tem perature line until the maximum certified altitude of 14,000 feet is reached.

14

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8

6

4

2

0

-1

-54 -50 -40 -30 -20 -10 0 1 0 2 0 3 0 4 0 50 60 M AXIMU M CER TIFIED 14,000'

TEM P + 10 DE G. STANDARD DAY

Figure 5-8. Maximum Certified Temp + 10.

Figure 5-8 depicts the last line on the tem perature vs. Altitude graph. This graph,

and all the charts in the takeoff section of the performance manual, are extended by 10 degrees to allow assumed temperat ure to be used in computing reduced power takeoffs. Now look at the environmental envelope.**KC-10 Aircrew Training System**

**Introduction to KC-10 Takeoff Performance**

CH 5

W831-05 5-7 01 JUL 13 Figure 5-9. The Environmental Envelope.

Here is the complete Environmental Envelo pe (figure 5-9). The KC-10 is certified to operate within this range of temperatures and altitudes.

1 ALTITUDE: -1,000 FEET TO 14,000 FEET.

2 TEMPERATURE: -54 TO 50 DEGR EES C. NOT TO EXCEED STD DAY + 40 ABOVE 2,400 FEET.

3 BREAK POINT: DEFINES TH E LOWER LIMIT FOR ASSUMED

TEMPERATURE.

4 MAX TEMP + 10: DEFINES THE UPPER LIMIT FOR ASSUMED

TEMPERATURE.

These temperature and altitude grid li nes are repeated in each performance chart that deals with temperature and pressu re altitude as a function of thrust available. Operation outside of this envelope is not pe rmitted. Take a look at

one of the charts in the takeoff section of the performance manual. 14

12

10

8

6

4

2

0

-1

-54 -50 -40 -30 -20 -10 0 1 0 2 0 3 0 4 0 5 0 6 0 STANDARD DAY ENVIRONMENTAL 1

4 2 STANDARD DAY 3

FLAT RATED THRUST

2 <

> <

1 BREAK POINT TEMPERATURE PLUS 40 DEG.

ENVELOPE PLUS

10 DEG.**KC-10 Aircrew Training System**

**Introduction to KC-10 Takeoff Performance**

CH 5

W831-05 5-8 01 JUL 13 Figure 5-10. Chart Design.

Figure 5-10 is a replica of Sheet 5 of the Climb Gradient Limiting Weight series.

All charts that are enter ed with temperature and pressure altitude have these same grids. You should recall the Envi ronmental Envelope pl ots. Here are those same plots with the altitude grids reversed and the same lines plotted on the performance chart.

Now look at Thrust Settings for Takeoff. Reduced power takeoffs permitted

inside this area

Heavy line represents Break Point of Environmental Envelope and the Minimum Assumed Temperature as a function of Altitude.

Dashed line represents Upper limit or Maximum Assumed Temperature as a function of Altitude. (Environmental Envelope + 10°)

.**KC-10 Aircrew Training System**

**Introduction to KC-10 Takeoff Performance**

CH 5

W831-05 5-9 01 JUL 13 5.3 POWER REQUIREMENTS

Conditions permitting, full rated thrust is seldom used for normal operations. Where possible, thrust is reduced to match the environmental and weight conditions for the assigned mission. Here are the conditions that require a full power takeoff:

Reduced thrust usage is not permitted if:

■ RCR value is less than 10.

■ RSC is used for TOLD computations.

■ The anti-skid braking system or one main gear wheel brake is inoperative.

■ One center gear wheel brake is inoperative and takeoff gross weight is greater than 460,000 pounds.

■ Headwinds are used for mission accomplishment.

■ Suspected windshear is reported.

■ Commercial Type II deicing/anti-icing fluid has been applied.

NOTE

The takeoff performance of the aircraft is not affected by the application of MIL SPEC or Commercial Type IV deicing/anti-icing fluid.

Figure 5-11. Power Set by 80 Knots.

In order to guarantee charted takeoff performance, takeoff power must be
established between 40 and 80 knots. After 80 knots, no adjustments are made except to prevent engine overboost. Takeoff Rate d Thrust is permitted up to 2,000 feet above the takeoff altitude, not to exceed five minutes for three engine operation and 10 minutes with an engine out (figure 5-11). These limits are valid for full and reduced power takeoffs.

Before you continue, take a look at t he relationship between temperature, throttle position, and N 1 RPM. POWER SET BY 5 M I N U T E S - 3 E N G

I N E S

1 0 M

I N U T E S - 2 E N G

I N E S

FIELD ELEVATION 2,000'

80 KNOTS**KC-10 Aircrew Training System**

**Introduction to KC-10 Takeoff Performance**

CH 5

W831-05 5-10 01 JUL 13 Figure 5-12. Throttle, Temp, and RPM.

As stated before, a flat ra ted engine is capable of pro ducing a given amount of thrust over a wide range of environmental conditions. Because of this, it is capable of producing an enormous amount of power at very low ambient temperatures. The area of the chart (f igure 5-12) bordered in heavy black lines represents the area where full throttle is required to produce the predicted thrust.

From the bottom of the environmental env elope to the maximum certified altitude as a function of temperature, the thrust will remain the same for a given altitude from -54 degrees C. to the Break Point Temperature.

At the Break Point, full throttle will be reached. From that point, up to the

maximum allowable ambient te mperature, the thrust and N 1 RPM will decrease.

This area is shaded and in side the thick ou tlined area in Figure 5-12 and in the blackened area in Figure 5-13. 14

12

10

8

6

4

2

0

-1

-54 -50 -40 -30 -20 -10 0 10 20 30 40 50 60 AREA OF CONSTANT POWER - FULL

N1

PART FULL BREAK POINT

N1 PART THROTTLE THROTTLE

AREA

THROTTLE THROTTLE**KC-10 Aircrew Training System**

**Introduction to KC-10 Takeoff Performance**

CH 5

W831-05 5-11 01 JUL 13 Figure 5-13. Throttle, Temp, and RPM.

Figure 5-13 depicts the Sea Level altitude line with N 1 RPM and representative throttle positions for a se ries of temperatures:

(1) -30 Deg C. 101.9% (2) -20 Deg C. 103.9% (3) 0 Deg C. 108.0% (4) +20 Deg C. 111.9% (5) +30 Deg C. 113.7%
- Breakpoint (6) +50 Deg C. 108.4%

Note that as the temperature incr eases, the throttle and RPM increase proportionally until the break point is reached. From the break point to the maximum allowable temperature, the thrust and RPM decrease

.

Now look at the concept, methodology, and procedures involved in computing
reduced thrust takeoffs.

14

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8

6

4

2

0

-1

-54 -50 -40 -30 -20 -10 0 1 0 2 0 3 0 4 0 5 0 6 0

101.9 103.9 108.0 111.9 113.7 108.9

(1) (2) (3) (4) (5) (6)

BREAKPOINT RPM

DECRE ASE**KC-10 Aircrew Training System**

**Introduction to KC-10 Takeoff Performance**

CH 5

W831-05 5-12 01 JUL 13 5.4 REDUCED POWER TAKEOFFS

Many years ago, several airlines and aircraft manufacturers commissioned a feasibility study to determine the maint enance cost savings if reduced takeoff thrust were used in day-to-day operat ions. Baseline data were developed and
several models were sent to the FA A for approval. The FAA approved two procedures and set down restrictions where, in their opinion, safety was a factor. The FAA approval was based in part, on the following factors:

● Thrust may not be decreased more than 25 percent of takeoff rated thrust.

● The operator must establish a procedur e to identify an engine incapable of producing takeoff rated thrust.

● The operator must develop procedures to assure that safety is not compromised, and submit those plans to the FAA for approval prior to implementing such procedures.

There are two approved methods for det ermining reduced power for takeoff. One is a flat percentage of available th rust, based on predetermined airfield data,
and the other is based on the amount of thrust available in excess of the amount required, based on aircraft and environmental conditions.

● Flat Percentage Based on Airfield Analysis:

Limited Use.
Not Valid for all Stations. Used only on a Dry Runway.
Does not make use of all Excess Thrust Available. Only Two Options--Full Derate or No Derate.

● Based on Environmental and Aircraft Conditions:

Totally Flexible. Use at any Station.
Maximum Use of Excess Thrust. Always within FAA Tolerances.
Allows for Partial Reductions.

The KC-10 uses the second method. It is based on a simple argument: If the maximum allowable gross weight for ta keoff is based on temperature and pressure altitude, then for every pound weight less than maximum there is a temperature at which that gr oss weight would be the maximum allowable. This is called Assumed Temperature and is the basis for reduced thrust takeoffs in the
KC-10.**KC-10 Aircrew Training System**

**Introduction to KC-10 Takeoff Performance**

CH 5

W831-05 5-13 01 JUL 13 Figure 5-14. Thrust Reduction VS. RPM.

Figure 5-14 illustrates power reduction based on assumed temperature. In this case the OAT is 30 degrees C. at Sea Level. The performance charts tell you

that with these conditions the maximum temperature would be 50 degrees C.

This would reduce the N 1 RPM by 8.5% for a net thrust decrease of 15%.

Now take a look at the charts involv ed in determining the Maximum Allowable Takeoff Gross Weight, for the existing te mperature, or the maximum allowable temperature for the existing gross weight. 0 0

3 0 1

2

3

4

5

6

7

8

9

1 0

1 1

1 2 3 .4

3 5 *

* 7 .6

4 0 1 1. 2

4 5 *

*

*

* 1 5. 0

5 0 1 8.4

5 5 *

*

*

*

*

6 0 2 0. 2 THRUST R EDUCTION - % THR U ST RED U C TION = DE LTA N 1 (%) X 1.8 CO NDITIONS :

ENGINES:

A M BIE NT TEM P E RATUR E:

P RES SU RE AL TITU DE: CF6 -50 C2

3 0 DEG . C.

SEA LEVEL

N 1

R

P

M %

A SS UMED TE MPE RAT URE 8.5%**KC-10 Aircrew Training System**

**Introduction to KC-10 Takeoff Performance**

CH 5

W831-05 5-14 01 JUL 13 Figure 5-15. Maximum Allo wable Takeoff Gross Wt.5°RALW 504.018°FLAP SETTINGMTOGW 544.0RA = 10,000’EFL = 9,750’25°CGLW 518.020°CMAXIMUM TAKEOFF GROSS WEIGHT ATOPTIMUM TAKEOFFFLAP SETTINGRCR = 23 to 18 / WITH REVERSE THRUSTREDUCED THRUST TAKEOFF20°CSHEET 1SHEET 2SHEET 3SHEET 4SHEET 5UNCORRECTEDCGLW 524.0**KC-10 Aircrew Training System**

**Introduction to KC-10 Takeoff Performance**

CH 5

W831-05 5-15 01 JUL 13 Figure 5-15 depicts a series of five charts in the Takeoff Section of the Performance Manual. Sheets one and two yield a runway available gross weight at five degrees of flaps. Sheets five and four yield a climb gradient limiting weight at 25 degrees flaps. Sheet three c onverts these weights to a Flap Setting

and Maximum Allowable Takeoff Gross Wei ght. The conditions yield a Maximum Weight of 544,000 pounds at a Flap Setting of 18 degrees. If the actual gross weight of the aircraft is less than t he MTOGW, then there is excess thrust

available.**KC-10 Aircrew Training System**

**Introduction to KC-10 Takeoff Performance**

CH 5

W831-05 5-16 01 JUL 13 Figure 5-16. Maximum Allowabl e Temperature VS. Weight.**KC-10 Aircrew Training System**

**Introduction to KC-10 Takeoff Performance**

CH 5

W831-05 5-17 01 JUL 13 Using the same set of charts, follow the flap line down to intersect the actual takeoff gross weight (figure 5-16). Para llel the weight grids to the RALW and CGLW at 5 degrees and 25 degrees respective ly. Using this RALW enter chart 2

and intersect the altitude line. Read the Te mperature at the botto m of the chart. In this case it is 47 degrees. Enter sheet 4 with the CGLW and apply the same

conditions. Continue on to sheet 5 and in tersect the altitude line and read the temperature at the bottom. In this case it is 44 degrees. The lowest of these two temperatures becomes the Assumed Tem perature and is used for all takeoff computations with the ex ception of Pressure He ight for Acceleration.**KC-10 Aircrew Training System**

**Introduction to KC-10 Takeoff Performance**

CH 5

W831-05 5-18 01 JUL 13 Figure 5-17. Area where Reduc ed Thrust is Permitted.

Here is the Environmental Envelope again (figure 5-17). The shaded area represents the limits of a ssumed temperature as a f unction of altitude. The assumed temperature may not be less t han the break point temperature, or higher than the environmental envelope plus 10 degrees. 14

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-1

-54 -50 -40 -30 -20 -10 0 10 20 30 40 50 60 STANDA RD DAY FLAT RATED THRUST STANDARD DAY ENVIRO NMENTAL

2 1

4 5 3

5 4 3 2 1 NOTE:

PRESSURE ALTITUDE FROM MINUS 1,000 TO 14,000 FT

TEMPERATURE FROM MINUS 54 TO 50 DEGREES C

AMBIENT TEMPERATURE MAY NOT EXCEED STANDARD DAY PLUS

40 DEGREES C ABOVE 2,400 FT PRESSURE ALTITUDE

THE ASS UMED TEMPERATURE MAY NOT BE LESS THAN THE

FLAT-RA TED BREAK POINT TEMPERATURE

THE ASS UMED TEMPERATURE MAY NOT EXCEED THE

ENVIRONMENTAL ENVELOPE BY MORE THAN 10 DEGREES C PLUS 40 DEGREES ENVELO PE PLUS

10 DEGREES

BREAK POINT TEMPERATURE**KC-10 Aircrew Training System**

**Introduction to KC-10 Takeoff Performance**

CH 5

W831-05 5-19 01 JUL 13 Figure 5-18. Assumed Temp. Limits on Charts.

The same information is available on any chart in the performance manual that has a temperature and altitude grid (fi gure 5-18). Minimum assumed temperature

is where the altitude line "bends" ; The maximum assumed temperature is where

it "ends"

. Reduced power takeoffs permitted

inside this area

Heavy line represents Break Point of Environmental Envelope and the Minimum Assumed Temperature as a function of Altitude.

Dashed line represents Upper limit or Maximum Assumed Temperature as a function of Altitude. (Environmental Envelope + 10°)

.**KC-10 Aircrew Training System**

**Introduction to KC-10 Takeoff Performance**

CH 5

W831-05 5-20 01 JUL 13 Figure 5-19. Runway Available Equals Critical Field Length (RA = CFL).

One other point before you finish this sect ion. Many aircrews are reluctant to perform reduced power takeoffs at any gros s weights above some arbitrary figure

that is within their comfort z one. This is mainly due to a misconception. It is said that reduced power takeoffs make ever y takeoff a "max effort", because when power is reduced, Critic al Field Length becomes Ru nway Available. For example, if the ambient temperat ure were 15 degrees and the assumed temperature were 50 degrees, a check of t he CFL charts would agree that RA = CFL, providing you enter the chart with 50 degrees

. A LL E N G IN E A C CE LE R A T IO N V 1

TW O ENGINE

A C C E LE R A T E /S T O P D IS TA N C E

CFL V R V LOF

RA = 10,000'

C FL = 10 ,00 0'

ASS UM ED TE MP ER ATU R E 50 E

AM BIEN T T EM PER AT U RE 15 E R UNW A Y

ACCELERATION**KC-10 Aircrew Training System**

**Introduction to KC-10 Takeoff Performance**

CH 5

W831-05 5-21 01 JUL 13 ASSUMED

TEMP

7 30 °

6 35 °

5 40 °

4 45 °

3 50 °

2 55 °

1 60 ° AMBIENT TEMP

15 °

15 °

15 °

15 °

15 °

15 °

15 °

Figure 5-20. Runway Available > Critical Field Length (RA > CFL).

There is an inherent "pad" or safety margin that results from the fact that the aircraft and engines are operating in the actual ambient temperature, and NOT in the assumed temperature . Since you are basing all speeds and distances on the assumed temperature, there is alwa ys additional runway available that is directly proportional to the spread betw een actual and assumed temperature. Figure 5-20 shows that relationship of add itional runway available as a function

of the difference in Actual and Assumed Temperature. The difference is greatest at the highest spread and decreases as assumed and actual temperatures

converge.ASUMED TEMP

DISTANCE**KC-10 Aircrew Training System**

**Introduction to KC-10 Takeoff Performance**

CH 5

W831-05 5-22 01 JUL 13 CFL = RA

30 30

15 E

CFL < RA 2 1

3

Figure 5-21. Assumed VS. Actual Temp

.

Here is another way of look ing at the same thing (fi gure 5-21). The temperature at the left is the ambient temperatur e and the temperature at the right is assumed. As the temperat ures become closer, until at some point they are equal. When the Assumed Temperature and the Actual Temperature are the same, then reduced thrust is TRT and Runway Available will equal Critical Field Length. 1 AS AMBIENT TEMP APPROACHES

2 ASSUMED TEMPERATURE

3 THE RA APPROACHES CFL**KC-10 Aircrew Training System**

**Introduction to KC-10 Takeoff Performance**

CH 5

W831-05 5-23 01 JUL 13 5.5 LESSON EXERCISE

1. The KC-10 is equipped with General Electric CF6-50C2 engines. They are

flat rated and the total thrust output varies wit h __________________,

________________________ ________, and ___________.

2. The engine instrument that shows the power output of the engines is the ________ indicator.

3. A flat-rated engine will produce a given amount of th rust over a wide range of

altitudes as a func tion of ___________________.

4. At a given altitude, the thrust w ill remain the same up to the ___________ ______________ temperature, then decrease proportional to the temperature.

5. Above 2,400 feet, the maximum allo wable ambient temper ature is standard day plus ___________ degrees.

6. The temperature grids in the performance manual exceed the environmental envelope by __________ degrees. This is to allow for ________ power

takeoffs.

7. The environmental envelope al titude grids are fr om __________ feet to ___________ feet.

8. The environmental envelope tem perature grids are from ___________ to __________ degrees, not to exceed st andard day plus 40 degrees.

9. Conditions permitting, full power tak eoffs are seldom used. Regardless of the type of takeoff being accomplished, takeoff power must be set prior to ________ knots.

10. As the temperature in creases from the bottom of the envelope, the N 1 RPM

will increase until the

________________________ _____ is reached. At that point, the N 1 RPM will decrease as a function of _______________.

11. The FAA approves reduced pow er takeoffs up to _________ percent.

12. The KC-10 uses the _______________ _____________ method for reduced power takeoffs.

13. The power setting for a reduced power takeoff is based on the lowest of

________________________ _____________ temperature or ___________ _______________________ te mperature.**KC-10 Aircrew Training System**

**Introduction to KC-10 Takeoff Performance**

CH 5

W831-05 5-24 01 JUL 13 14. The ___________________ __ temperature is the minimum allowable assumed temperature.

15. The Maximum Allowable Assumed temperature is t he environmental envelope plus _________ degrees.

16. The same information found in the En vironmental Envel ope can be found on any takeoff performance chart that has an ________________ and _____________ grid.

17. When making a reduced power takeoff, the critical fiel d length will always be equal to or less than runway avail able; the difference being the spread between the __________ temperature and the _____________ temperature.

18. The difference between the chart ed performance during a reduced power takeoff and the actual performance is because the aircraft and engines are operating in the actual temperature wh ile the distance and speed charts are entered with the __________ _ temperature.**KC-10 Aircrew Training System**

**Introduction to KC-10 Takeoff Performance**

CH 5

W831-05 5-25 01 JUL 13 5.6 LESSON EXER CISE ANSWER KEY

1. temperature/pressure altitude/velocity

2. N 1 RPM 3. temperature 4. break point

5. 40

6. 10/reduced 7. -1,000/14,000

8. -54/50

9. 80 10. break point temperature/temperature

11. 25 12. assumed temperature 13. runway available limit ing/climb gradi ent limiting 14. break point

15. 10 16. altitude/temperature

17. assumed/actual

18. assumed**KC-10 Aircrew Training System**

**Introduction to KC-10 Takeoff Performance**

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W831-05 5-26 01 JUL 13 THIS PAGE INTENTIONALLY LEFT BLANK**KC-10 Aircrew Training System**

**Introduction to KC-10 Takeoff Performance**

CH 5

W831-06 6-1 01 JUL 13 6.0 ENGINE-OUT TAKEOFF PROFILE

This is the final subject in this wo rkbook. It covers the engine-out climb profile from lineup to the end of the pressure hei ght for acceleration. You will use this profile and the associated events to expa nd and amplify the terms and definitions described in the previous segments. Y ou will cover the balanced field concept; determine the type of takeoff required fo r the conditions; compute obstacle distance and height; define the best speed for engine-out obstacle clearance; and cover the concept of the pressure hei ght for acceleration, to include the

effect of obstacles.

Figure 6-1. Engine Out Profile.

The following examples will us e this profile as a visual reference to discuss each event in the takeoff sequence (figure 6-1). Where speeds an d distances are a factor, the values for a brake release gross weight of 590,000 pounds, standard day conditions for sea level, and a runway available of 10,000 feet.**KC-10 Aircrew Training System**

**Introduction to KC-10 Takeoff Performance**

CH 5

W831-06 6-2 01 JUL 13 6.1 BALANCED FIELD CONCEPT

Figure 6-2. Balanced Runway Concept.

The KC-10 "Maximum Takeoff Gross Wei ght at Optimum Takeoff Flap Setting" charts attempt to balance the runway requ ired to accelerate to decision speed, lose a wing engine, and either continue t he takeoff on two engines or stop in the

same distance. That distance is Critic al Field Length. T here are 200 possible flap settings for takeoff; however, only one will yield a maximum gross weight that will satisfy the runway available limi ting weight and the c limb gradient limiting weight. OPTIMIZATION OF

TAKEOFF FLAP SETTING

ALLOWABLE

TAKEOFF REGIONGROSS WEIGHT ALL ENGINE ACCELERATION

CFL

STOP 

### OR CFL

V CEF ALL ENGINE ACCELERATION TWO ENGINE

ACCELERATION V CEF V LOF**KC-10 Aircrew Training System**

**Introduction to KC-10 Takeoff Performance**

CH 5

W831-06 6-3 01 JUL 13 6.2 TYPES OF TAKEOFFS

Figure 6-3. Static Takeoff.

A static takeoff may be accomplished if conditions permit. The procedure is to apply the brakes, advance the throttles to the approximate takeoff power setting, release the brakes, and establish the final power adjustment prior to 80 knots. The wind direction and velocity must be within the designated area of the Wind Component - Takeoff c hart (figure 6-4).**KC-10 Aircrew Training System**

**Introduction to KC-10 Takeoff Performance**

CH 5

W831-06 6-4 01 JUL 13 Figure 6-4. Rolling Takeoff.

Crosswind disturbs the engine inlet airflo w, especially when the brakes are set and takeoff power is applied. Because of this, a rolling takeoff must be performed if the wind direct ion is 45 degrees off runway heading or the crosswind component exceeds 23 knots. The rolling takeoff takes advantage of the forward momentum gained during taxi-on to the runw ay. As the aircraft is aligned for takeoff, the throttles are smoothly advanced to takeoff power. Takeoff power has to be set at 80 knots, if takeoff power is not set by 80 knots, charted takeoff performance may not be ac hieved (figure 6-4). TAKEOFF POWER SET: BRAKES RELEASED – POWER SET – 80 KNOTS**KC-10 Aircrew Training System**

**Introduction to KC-10 Takeoff Performance**

CH 5

W831-06 6-5 01 JUL 13 Figure 6-5. Lineup Distance.

The aircraft requires a minimum of 300 feet of runway for lineup (figure 6-5). This is a

nominal distance when the aircraft is taxied in to position from a poin t at the beginning of the runway. When unusual circumstances ex ist, such as a 180 degree turn or another entry point, then actual distance required should be used. This line-up distance is subtracted from the runway length or Ma x Liftoff Point (SDP) to determine runway

available for takeoff.

Figure 6-6. 80 Knots Power Set.

Figure 6-6. 80 Knots Power Set

Regardless of the type of takeoff being accomp lished, the Pilot Not Flying will call "80 Knots" and the Flight Engineer will ensure tak eoff power is set and state "Power Set".

The next event is De cision Speed, or V 1

. V SR MCT

V CEF (ENGINE FAILURE) V 2

300’

“EIGHTY KNOTS,

POWER SET”**KC-10 Aircrew Training System**

**Introduction to KC-10 Takeoff Performance**

CH 5

W831-06 6-6 01 JUL 13 6.3 DECISION SPEED/TIME

Figure 6-7. Decision Speed (V 1 ). Decision Speed ( V 1 ) is the higher of Critic al Engine Failure Speed (V CEF ) or Ground Minimum Control Speed (V MCG ), not to exceed Max Braking Speed (V MBE ). In this case,

V CEF is Decision speed, or 163 knots.

Figure 6-8. Decision Sequence. At Decision Speed, the Pilot has three sec onds of reaction time from an engine failure

to make the abort decision. Because number two engine is centerline mounted, two ENG FAIL lights are installed on the glare sh ield to alert the crew if an engine fails during takeoff ground roll. The system is armed when the N 1 is advanced past 85% and

is activated when an 11% difference or greater is det ected. At V 1 , the aircraft is accelerating at approximately 275 feet per second and will cover about 825 feet.  HIGHER OF V MCG OR V CEF  NOT TO EXCEED V MBE

3 SECONDS FROM V 1 WITH

TWO ENGINE ACCELERATION

ACCELERATE STOP DISTANCE

ALL ENGINE ACCELERATION STOP DISTANCE**KC-10 Aircrew Training System**

**Introduction to KC-10 Takeoff Performance**

CH 5

W831-06 6-7 01 JUL 13 Figure 6-9. Abort Sequence.

Once the decision is made to abort the ta keoff, there is a 1.1 second time frame of constant speed where the throttles are pulled to idle, maximum anti-skid braking is applied, full reverse thrust applied, and the spo ilers are deployed (figure 6-9). This will add another 300 feet to the total distance. The abort decision sequence, in this case, required approximately 1,125 f eet of runway. The aircraft will now stop in the remaining runway.

Figure 6-10. Takeoff Continued.

If the decision is made to c ontinue, the Pilot will maintain directional control using rudder and nose wheel steering wh ile the aircraft accelerates to Rotate Speed or

187 knots. STOP DISTANCE ALL ENGINE ACCELERATION**KC-10 Aircrew Training System**

**Introduction to KC-10 Takeoff Performance**

CH 5

W831-06 6-8 01 JUL 13 When performing a reduced thrust takeoff and an asymmetric power condition results from loss of a wing engine; advancing power to takeoff rated thrust on remaining engines prior to reaching 135 KIAS may result in insufficient lateral control and
aircraft may depart the confines of the runway since V MCG is calculated using assumed temperature.

Figure 6-11. WARNING.

The above WARNING (figure 6-11) applies only to reduc ed power takeoffs. 135 knots is chosen because it is the worst case, wet/icy V MCG / V R MIN . It would not apply to Rotate because V R MIN guarantees lateral control.

Figure 6-12. Rotate Speed (V R ).

The next event is Rotate Speed (V R ). This speed must be equal to or greater

than V R MIN . V R MIN is the wet/icy charted V MCG . In this case charted V R is 179

knots. The charted V R speed, which is 105% of minimum unstick speed (V MU ), has been increased by 8 knots above the basic DC-10 rotate speed to allow adequate boom clearance at rotate.**KC-10 Aircrew Training System**

**Introduction to KC-10 Takeoff Performance**

CH 5

W831-06 6-9 01 JUL 13 Figure 6-13. Distance During Rotate.

At V R , a four second time frame (figure 6-13) is allocated to allow the aircraft to be rotated from a three point attitude to an angle of attack that will allow

continued acceleration thr ough minimum unstick speed (V MU ) to liftoff speed (V LOF ). At 179 knots or 300 feet per seco nd, the four seconds equates to an approximate distance of 1,200 feet between V R and V LOF

.

Figure 6-14. Liftoff Speed (V LOF ).

At V LOF , the flight guidance system will command a pitch that will allow continued acceleration to Climbout Speed (V 2 ). This flight path assumes gear retraction is

initiated three seconds after liftoff and co mpleted 10.5 seconds later. From V LOF to 50 feet AGL, the aircraft is accelerated to V 2 (figure 6-14).**KC-10 Aircrew Training System**

**Introduction to KC-10 Takeoff Performance**

CH 5

W831-06 6-10 01 JUL 13 6.4 SPEED FOR BEST ANGLE OF CLIMB

Figure 6-15. Climbout Speed (V 2 ).

Climbout speed (V 2 ) is established at a height of 50 feet above the takeoff altitude and is maintained, with the flaps and slats in t he takeoff configuration, until the Pressure Height for Acceleration is reached (figur e 6-15). This speed satisfies the FAA requirement of 115% of the 1.0g stall speed. If Rotate Speed (V R ) was increased to equal V R MIN , then V 2 must be increased by the same increment.

Figure 6-16. Pressure He ight For Acceleration.

At the acceleration height, the aircraft is leve led off and the flaps a nd slats are retracted according to the recommended schedule. (Figure 6-16). 2 ENGINE

ACCELERATION STANDARD FLIGHT PATH

(LOSS OF AN ENGINE)

MCT

V SR

PRESSURE HEIGHT

FOR ACCELERATION 50 FT V 2 V CEF (ENGINE FAILURE)

V LOF V R V FR

80 KNOTS 80 KNOTS

PRESSURE HEIGHT

FOR ACCELERATION V LOF V 2

50’

ALL ENGINE

ACCELERATION

CFL**KC-10 Aircrew Training System**

**Introduction to KC-10 Takeoff Performance**

CH 5

W831-06 6-11 01 JUL 13 6.5 PRESSURE HEIGHT FOR ACCELERATION

Figure 6-17. Climbout Flight Path.

The two-engine pressure height for accele ration is the height that level off, acceleration and cleanup should be accomplis hed. This is done to ensure the climbout flight path for obstacle clearance is achieved. The charted pressure height is a base geometric height of 1,500 feet above the takeoff altitude, based on standard day temperatures. This ba se height is adjusted up or down to

account for non-standard c onditions (figure 6-17). CLIMBOUT FLIGHT PATH

PRESSURE HEIGHT

FO ACCELERATIONOBSTACLE HEIGHT ABOVE LIFTOFF CLIMBOUT FLIGHT PATH

7.0 3.88

6.0

5.0

3.88

3.0 3.5 3.0 3.5

2.5

2.5**KC-10 Aircrew Training System**

**Introduction to KC-10 Takeoff Performance**

CH 5

W831-06 6-12 01 JUL 13 Figure 6-18. Two Engine Press ure Height For Acceleration.

The minimum height for acceleration with an engine inoperativ e is based on two conditions: Pressure Height for Acce leration or 400 feet above the runway (AGL). Pressure Height for Accelerati on is based on obst acle clearance height and accounted for with the computed climb gradient. (figure 6-18). CHARTED PRESSURE HEIGHT FOR ACCELERATION

400’ AGL (Does Not Ensure Obstacle Clearance) o r 2

1**KC-10 Aircrew Training System**

**Introduction to KC-10 Takeoff Performance**

CH 5

W831-06 6-13 01 JUL 13 6.6 OBSTACLE HEIGHT AND DISTANCE COMPUTATIONS

Figure 6-19. Distant Terrain Clearance.

Remember, after operating at takeoff rated thrust for ten minutes or upon reaching 2000 feet pressure al titude above the airfield, wh ichever occurs first, the thrust is reduced to MCT. Clearing dist ant obstacles, such as high terrain, is predicated on leveling off at the pressure height for a cceleration, retracting the flaps and slats, and climbing at slat re tract speed until terrain clearance is achieved or the minimum height for enroute operations is reached. Now look at some procedures for defining obstacles. STANDARD FLIGHT PATH

( LOSS OF AN ENGINE ) MCT

V SR V FR V CEF (ENGINE FAILURE) V 2

V LOF V R 80 KNOTS

2 ENGINE

ACCELERATION PRESSURE HEIGHT

FOR ACCELERATION 50 FT

LEVEL OFF AND

ACCELERATE

AT CHARTED

PRESSURE HEIGHT

FOR ACCELERATION MCT AT V SR DISTANT

TERRAIN ALL ENGINE

ACCELERATION**KC-10 Aircrew Training System**

**Introduction to KC-10 Takeoff Performance**

CH 5

W831-06 6-14 01 JUL 13 Figure 6-20. Obstacle Height & Distance.

You recall that the obstacl e distance is measured from the Departure End of the Runway (DER). The height is listed as above mean sea level (MSL). Remember, field elevation on the TOLD ca rd is the highest point on the airport’s usable runways. If the runway has no slope, then simply subtract the field elevation from the obstacle height to find the actual obstacle height AGL (figure 6-20). 846 -746

100'AGL 1 1 846'

OBSTACLES

SPOT ELEVATION

OBSTACLE

HIGHEST OBSTACLE HIGHEST SPOT ELEVATION

GROUP OF OBSTACLES

DOUBTFUL ACCURACY**KC-10 Aircrew Training System**

**Introduction to KC-10 Takeoff Performance**

CH 5

W831-06 6-15 01 JUL 13 Figure 6-21. Airfield Diagram.

Most Flight Information Publications in us e today have Airfield Diagrams and Standard Instrument Departures included. The Airf ield Diagrams have the Departure End of Runway Elevation or DER Elev (figure 6-21) list ed and the SIDs have the controlling obstacles identified for the specific departure route. If the DER elevation is known, subtract this from the obstacle height to obtain the obstacle height AGL. DER

ELEV**KC-10 Aircrew Training System**

**Introduction to KC-10 Takeoff Performance**

CH 5

W831-06 6-16 01 JUL 13 OBSTACLE IS 100' ABOVE FIELD ELEVATION

FIELD RW

SLOPE 1.2% 1,300 MSL

ELEVATION

1,200' LENGTH

12,200' OBSTACLE IS 100' ABOVE FIELD ELEVATION

FIELD RW

SLOPE 1.2% 1,300 MSL

ELEVATION

1,200' LENGTH

12,200'

Figure 6-22. DER Elevation Not Known.

If the departure end of the runway elevat ion is unknown and you are using field elevation to compute the obstacle heig ht, you must correct the published obstacle height for downhill runway slope. Figure 6-22 shows an obstacle at 1,300 MSL with a field elevation of 1,200 fee t. If you subtract the field elevation from the obstacle height you would find the obstacle hei ght to be 100 feet AGL. However, the runway shows a 1.2 percent downhill gradient. No w look at figure
6-23.

OBSTACLE HEIGHT (AGL) = OBST HT (MSL) - 

## ( FIELD ELEVATION - RUNWAY LENGTH X SLOPE 

## )

100

Figure 6-23 Formula

To determine obstacle height above ground level (AGL) with a downhill slope:

a. Multiply the runway l ength by the runway slope. 12,200 x 1.2 = 14,640 b. Divide the result by 100. 14,640 / 100 = 146.4
c. Subtract the result fr om the field elevation. 1,200 - 146 = 1054 d. Now, subtract this number from the obstacle height (MSL). 1,300 - 1054 = 246 e. This is the corrected obstacle height (AGL). 246 feet (AGL)

Note : If you use the "percent" (%) function of your computer, skip the "divide by 100" step.**KC-10 Aircrew Training System**

**Introduction to KC-10 Takeoff Performance**

CH 5

W831-06 6-17 01 JUL 13 Figure 6-24. Result.

Here you see the result of your calculat ion and the necessity fo r it (figure 6-24). The obstacle is only 100 feet above the fi eld elevation. However, the downhill slope takes you below the obstacle. The obstacle is actually 246 feet above the departure end of the runway. The last 146 feet of that water tank would ruin your whole day!! OBSTACLE IS 100' ABOVE FIELD ELEVATION

FIELD RW

D

O

W

N H I L L S L O P E 1,300 M S BUT

OBSTACLE IS 246' ABOVE DEPARTURE END OF RUNWAY

146' ADDITIONAL ELEVATION

1,200' LENGTH

12,200' 1,300 MSL**KC-10 Aircrew Training System**

**Introduction to KC-10 Takeoff Performance**

CH 5

W831-06 6-18 01 JUL 13 Figure 6-25. Delta Obst acle Height Correction.

Even if the departure end of the runway elevation is known, any downhill slope must be applied to the obstacle height prior to entering the climb gradient

chart . This has nothing to do with elevation, but rather the aircraft downhill trajectory. The momentum of an aircraft with the mass of the KC-10 is such that

it will take the aircraft below the charted flight path. “A” in figure 6-25 shows the charted vs. actual flight pat h with no correction. “B” in figure 6-25 shows the flight path after the delta height correction. T here is a chart for close-in obstacles, and a standard 24 feet for each one percent of runway slope for the rest. (NOT CORRECTED**KC-10 Aircrew Training System**

**Introduction to KC-10 Takeoff Performance**

CH 5

W831-06 6-19 01 JUL 13 Figure 6-26. Runway Reduction.

Because of the way KC-10 takeoff perfo rmance is calculat ed, with engine out liftoff at the end of the runway, there are times when close-in obstacles require a climb gradient in excess of 9.0%. Since 9.0% is the highest gradient available,

the distance to the obstacle must be increased by decreasing the runway available by a like amount (figure 6-26). Both uphill and downhi ll slope is applied to the decreased runway increment and the obs tacle height adjust ed accordingly. This procedure will be covered in detail in another workbook.**KC-10 Aircrew Training System**

**Introduction to KC-10 Takeoff Performance**

CH 5

W831-06 6-20 01 JUL 13 6.7 SPECIAL DEPARTURE PROCEDURE

The Air Force Flight St andards Agency (AFFSA) has contracted with Jeppesen to provide safe engine out departure procedures for bases used by the KC-10 to provide the maximum takeoff weight po ssible and miss any obstacles should an engine fail during takeoff. Special Departure Procedur e information is found at “http://www.jeppesen.com” on the Internet.

Jeppesen analyzes terrain and obstacle data against aircraft specific performance data to determine the best engi ne out departure and takeoff weight for each runway at a given location. Username and passwords change periodically; please contact your instructor or squadron for cu rrent information. Once logged into the website, click on OpsData, which will take you to the OpsData Search menu. Now select KC -10A/A/CF6-50C2 under Aircraft and type in Airport Keyword (ICAO identifier). The next screen will a llow you to view specific airport data. You can also select the View Entire List to allow selection of any airfield within the data base.

A User Guide can be viewed or downloade d and is also available below the Ops Data menu. Only bases that have approved procedures are listed on the Jeppesen website. This w ebsite should be checked duri ng mission planning. If an approved procedure is avai lable, it must be brie fed and used if an engine

failure occurs on takeoff. TOLD and/or SDP departure plate information can be found on the website, and has been approved by the Air Force for TOLD computations.

Complete the lesson exercise prior to continuing.**KC-10 Aircrew Training System**

**Introduction to KC-10 Takeoff Performance**

CH 5

W831-06 6-21 01 JUL 13 6.7 LESSON EXERCISE

1. The concept that the distance to c ontinue the takeoff on two engines or stop in the same distance is called the ________________________ concept.

2. The "Maximum Takeoff Gross Wei ght at Optimum Flap Setting" charts attempt to balance the runway requi red for takeoff by varying the ____________ setting based on runway av ailable and required climb gradient.

3. A static takeoff may be accomplis hed if the wind dire ction is less than __________ degrees off the r unway heading or the crosswind component is ________ knots or less.

4. At V 1 the Pilot has _________ seconds of reaction time from an engine

failure and make the abort decision.

5. If the decision is made to ab ort the takeoff, ____________ seconds are allocated to bring the throttles to idle and commence the abort process.

6. The engine fail system is armed when the N 1 is advanced past __________ and is activated when an ___________ differenc e or greater

is detected.

7. When performing a reduced power takeo ff, takeoff rated thrust may not be applied until an airspeed of 135 knots. This is because Ground Minimum Control Speed has been com puted using ________________ Temperature.

8. Rotate Speed may never be lower than V MCG ___________/________,

which is V R MIN

.

9. The KC-10 is rotated from a three- point attitude to an angle of attack that will allow enough lift to become airborne at V LOF . This will take approximately _______ seconds.

10. The flight path assumes that gear retraction is initiated _______ seconds after liftoff and completed __________ seconds later.

11. From Liftoff to a height of________ feet, the aircraft is accelerated to __________ speed (V 2 ).

12. If Rotate Speed was increased to equal V R MIN , then _____________ must be increased by the same increment.**KC-10 Aircrew Training System**

**Introduction to KC-10 Takeoff Performance**

CH 5

W831-06 6-22 01 JUL 13 13. Engine out climbout speed is mainta ined using takeoff power for ten minutes or ____________ feet pressure altitude above the airfield,

whichever occurs first. Power is then reduced to

__________ .

14. The two engine minimum pressure height for acceleration is __________ feet AGL; the height of the ______________________ ________; or charted _________ __________ for _________________.

15. The only means to guarantee distant obstacle clearance is to level off at

________________________ _______________, cleanup, and maintain _____________________ speed until the obs tacle is cleared or the minimum altitude for enroute operations is reached.

16. Obstacle distance is the horizon tal distance from the ______________ end of the runway to the obstacle.

17. Obstacle height is depict ed as height above __________________.

18. Field Elevation is the highest point on the runway surface. It may be used to compute obstacle height if the runway has no ___________.

19. If the elevation at the departure end of the runway is not known, and a downhill slope exists, the actual obsta cle height can be calculated using the runway ________ times the runway slope in percent, and that height added to the obstacle height as computed from the field elevation.

20. In all cases, a downhill slope will require a obstacle height correction to account for the ____________________ _____ of the aircraft.

21. In some cases, when the clim b gradient required exceeds 9.0%, the

distance to the obstacle must be incr eased. This is done by decreasing the _____________________ until a gr adient of 9.0% or less is attained.**KC-10 Aircrew Training System**

**Introduction to KC-10 Takeoff Performance**

CH 5

W831-06 6-23 01 JUL 13 6.8 LESSON EXER CISE ANSWER KEY

1. balanced field 2. flap

3. 45/23

4. 3

5. 1.1

6. 85%/11%

7. assumed 8. wet/icy

9. 4

10. 3/10.5

11. 50/climbout

12. V 2 13. 2,000/MCT 14. 400/controlling obstacle/pr essure height/acceleration 15. pressure height for acceleration/slat retract 16. departure

17. mean sea level 18. downhill slope 19. length 20. downhill trajectory 21. runway available**KC-10 Aircrew Training System**

**Introduction to KC-10 Takeoff Performance**

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