## W-834 01 Jul 13



## W839KC-10 Aircrew Training System

Driftdown

CH 4

W839-LEP A 01 JUL 13 INSERT LATEST CHANGED PAGES. DESTROY

SUPERSEDED PAGES.

NOTE: A vertical line in the outer margin of the page indicates the portion of text affected by the changes.

Dates of issue for original and changed pages are:

Original

. . . . 0

. . . . . 01 Mar 06 Change

. . . . 3

. . . . . 01 Jul 11

Change

. . . . 1

. . . . . 01 Jul 08 Change

. . . . 4

. . . . . 01 Jul 13

Change

. . . . 2

. . . . . 01 Apr 10

Page

No. *Change

No.

Title

. . . . . . . . . . . . . 4

A

. . . . . . . . . . . . . . 4

i – ii

. . . . . . . . . . . . . 0

1-1 – 1-2

. . . . . . . . . . . 2

2-1 – 2-2

. . . . . . . . . . . 2

3-1 – 3-12

. . . . . . . . . . 4

4-1 – 4-4

. . . . . . . . . . . 4

5-1 – 5-20

. . . . . . . . . . 4

6-1 – 6-6

. . . . . . . . . . . 0

Summary of Action (s); 1. Biennial review completed.

* Zero in this column indicates an original page. 

### LIST OF EFFECTIVE PAGESKC-10 Aircrew Training System

Driftdown

Original

W839-TOC i 01 MAR 06 TABLE OF CONTENTS

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

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

3.0 TERMINOL OGY ................................................................................................ 3-1

4.0 BASIS FOR TERRAI N CLEARANCE ................................................................ 4-1

5.0 DRIFTDOWN PROC EDURES .......................................................................... 5-1

6.0 LESSON EXER CISE ......................................................................................... 6-1KC-10 Aircrew Training System

Driftdown

Original

W839-TOC ii 01 MAR 06 THIS PAGE INTENTIONALLY LEFT BLANKKC-10 Aircrew Training System

Driftdown

CH 2

W839-01 1-1 01 APR 10 1.0 INTRODUCTION

Driftdown is the procedure used when cruise altitude cannot be maintained due to the shutdown of one or more engines. Maximum Continuous Thrust, or MCT, is used for driftdown. It is applied at the start of the dr iftdown procedure and maintained until the power is reduced for the approach and landing.

The KC-10 Performance Manual does not provide altitude and terrain clearance

charts in the Driftdown Section for the lo ss of a single engine. Reasonable cruise altitudes, sufficient for all terrain clearance, can be ma intained with two engines operating with the aircraft at normal operating weights. Information concerning two-engine operation may be found in the Cruise Section of the Performance

Manual and the Abnormal Procedures section of the Flight Manual.

This workbook addresses single engine driftdown terminology and procedures. Five scenarios will be presented:

1. A driftdown prof ile where neither gross weight

, terrain, or range are limiting factors. (Complet e Profile not required)

2. A driftdown profile where gross weight and terrain clearance are limiting and range is not a factor. (D riftdown Profile Required)

3. A driftdown profile where gross weight and range are limiting and terrain is not a factor. (Drift down Profile Required)

4. A driftdown profile where enduranc e range and time must be calculated.

5. Typical driftdown profile illustrated.KC-10 Aircrew Training System

Driftdown

CH 2

W839-01 1-2 01 APR 10 THIS PAGE INTENTIONALLY LEFT BLANKKC-10 Aircrew Training System

Driftdown

CH 2

W839-02 2-1 01 APR 10 2.0 OBJECTIVES

When you finish this workbook, you will be able to:

1. Identify terminology a ssociated with Driftdown Pe rformance Computations.

2. Identify conditions effecting Dr iftdown Performance Computations.

3. Compute Driftdown Performance Data.KC-10 Aircrew Training System

Driftdown

CH 2

W839-02 2-2 01 APR 10 THIS PAGE INTENTIONALLY LEFT BLANKKC-10 Aircrew Training System

Driftdown

CH 4

W839-03 3-1 01 JUL 13 3.0 TERMINOLOGY

3.1 Driftdown Profile

Figure 3-1. Driftdown Profile.

Driftdown is a forced descent resulting fr om the loss of power from one or more engines. In the event of a loss of an engine(s) above the maximum service ceiling for the number of engines still operating, driftdown becomes a necessary procedure. Driftdown is not a "Checklist Procedure" unto itself, but rather a part of other checklists. For instance, Dri ftdown is a directed checklist procedure
under the "SINGLE ENGINE OPERATION (UNLESS COMMITTED ON FINAL)" Emergency Checklist.

This profile, Figure 3-1, will be followed for all single engine operation, with two exceptions. Single engine operation at low altitudes , where driftdown is not required, and when single engine operation is required after descent has been established for landing.

1 Loss of Second Engine. MCT Set/Maintain Altitude until MACH 0.82/280

KIAS. 2 Driftdown speed established. F uel dump initiated, if required. 3 Air Conditioning Packs Off at 10,000 feet.

4 Level off and accelerate to 270 KIAS. 5 Begin Cruise- Climb at 270 KIAS. 6 Level off at 10,000 feet. Maintain 270 KIAS until the cr uise-climb weight with one air conditioning pack ON is attained.

7 Continue cruise-climb at 270 KIAS to destination. 2

3

4

5 7

6 SINGLE ENGINE DRIFTDOWN

PROFILEKC-10 Aircrew Training System

Driftdown

CH 4

W839-03 3-2 01 JUL 13 Figure 3-2. Driftdown Altitude Capability.

Figure 3-2. Driftdown Altitude Capability. 6,600

420KC-10 Aircrew Training System

Driftdown

CH 4

W839-03 3-3 01 JUL 13 3.2 Driftdown Altitude Capability

The chart in Figure 3-2 is based on the absolute maximum altitude attainable with one engine operating at MCT. It is valid for temperatures up to standard day plus 15 degrees C. Ther e is another identically c onstructed line to provide information for a temperature of standard day plus 20 degrees C.

This chart provides the same data as the "Instantaneous Gross Weight"

Tabulated Data in the SINGLE ENGIN E OPERATION Abbreviated Checklist.

It is not used for terrain clearance driftdown co mputations. It is, however, used when the aircraft is operating on a single engine, but the dri ftdown profile is not required.

3.3 Instantaneous Gross Weight

Figure 3-3. Altitude Capabilit y-Instantaneous Gross Weight.

Figure 3-3 is an extract of part of t he SINGLE ENGINE OPERATION Checklist. Notice that the tabulated data exactly matc hes the information provided in Figure

3-2. Also note that t he decision arrow is pointing to DRIFTDOWN REQUIREDNO . Assume a two- engine approach at 420,000 pounds. Now, assume the failure of a second engine at 8,000 fee t. This chart yields the following:

INSTANTANEOUS GROSS WEIGHT.........................................420,000 lbs

INSTANTANEOUS ALTI TUDE..........................................................6,600' INSTANTANEOUS

GROSS WEIGHT (X 1,000 LB) AT DRIFTDOWN SPEED

TO STD + 15°c STD + 20°C

ALTITUDE (FT)

300 16,500 16,300

320 14,700 14,100

340 12,700 12,000

360 10,800 10,000

380 10,000 9,100

400 8,500 6,800

420 6,600 4,300

440 4,600 1,800

460 2,500 0

480 0 0 DRIFTDOWN REQUIRED NO

NOTE

ICE PROTECTION OFF.

MAX CONTINOUS THRUST.

REDUCE ALTITUDE CAPABILITY BY 1,000 FEET FOR ENGINE PLUS

WING ANTI-ICE ON. ALTITUDE CAPABILITYKC-10 Aircrew Training System

Driftdown

CH 4

W839-03 3-4 01 JUL 13 3.4 Gross Vs. Net Performance

Figure 3-4. Gross Vs. Net Performance.

Gross Performance is defined as the actual aircraft performance capability.

Net performance is the gross performance level minus 0.3% gradient capability performance. It provides approximately 2,000 feet lower alti tude capability, and a five percent increase in fuel flow when compared to gross performance.

All driftdown charts in the Perform ance Manual and Checklist are based on Net

Performance.KC-10 Aircrew Training System

Driftdown

CH 4

W839-03 3-5 01 JUL 13 Figure 3-5. Driftdown Speed.KC-10 Aircrew Training System

Driftdown

CH 4

W839-03 3-6 01 JUL 13 3.5 Driftdown Speed

DRIFTDOWN SPEED SCHEDULE

ALTITUDE (X 1,000) GROSS WEIGHT (X 1,000 LB)

300 325 350 375 400 425 450 475 500 525 550 575

KIAS

SL 213 222 231 239 247 254 262 269 276 282 289 296

5 214 223 232 240 248 255 263 270 277 284 291 297

10 215 224 233 241 249 256 264 271 278 285 292 299

15 216 225 233 242 250 257 265 272 279 286 293 300

20 216 225 234 242 251 258 267 274 280 288 295 304

25 218 227 236 244 253 261 269 276 284 291 298 306

30 219 228 238 246 255 263 271 279 287 295 302 310

35 221 231 240 250 259 268 276 284 293 300 308

–

40 224 234 244 254 264 272 282

– – – – –

42 226 236 247 256 266

– – – – – – –

Figure 3-6. Driftdown Speed.

Recommended driftdown speeds are publis hed in the Driftdow n Section of the Performance Manual (Fig. 3-5) and the Single Engine Operation Checklist (Fig. 3-6). These speeds provide optimum driftd own performance. Deviations of plus

or minus ten knots will resu lt in negligible loss of performance. The Flight Engineer should update the s peed periodically (every 5,000 feet). The Pilot uses the updated speeds to flatten out the de scent profile thus improving range capability. The terrain clearance c apability, time, and range are based on maintaining this speed to the bottom of driftdown.KC-10 Aircrew Training System

Driftdown

CH 4

W839-03 3-7 01 JUL 13 3.6 Geometric Altitude

Figure 3-7. Geometric Altitude.

Obstacles and terrain are depicted as geometric height above mean sea level (MSL). The charted performance data are based on standard day pressure

altitude. Since most dri ftdown scenarios start out above the transition altitude, your altimeter setting will be 29.92 and th e area altimeter setting may not be known. This chart (Fig. 3-7) converts geometric height to a pressure height as a function of temperature. Notice that at standard day temperatures the geometric and pressure heights are identical . Also note that as the altitude increases the difference in pres sure height and geometric height diverge as a function of temperature

.KC-10 Aircrew Training System

Driftdown

CH 4

W839-03 3-8 01 JUL 13 3.7 Cruise Climb Altitude Capability

Figure 3-8. Cruise Climb Capability.

This chart (Fig. 3-8) provides data to ca lculate the maximum altitude that can be maintained with one engine operating at Maximum C ontinuous Thrust while maintaining 270 KIAS. During Cruise Clim b, the aircraft is allowed to climb as the gross weight is reduced by fuel consumption. The re sulting rate of climb will be slight, and will result in the absolute maximum nautical miles per pound of fuel expended. All charted per formance data for driftdown are based on maintaining this airspeed and power setting until destination.

This chart is identical to the Driftdown Altitude Capability Chart except that this

chart is based on a constant 270 KIAS in stead of variable driftdown speeds. B O T T O M -O F-DR IF T DO W N G R O S S W IE G HT (1 00 0 lb s) CRUISE-CLIMB

ALTITUDE CAPABILITYPRESSURE ALTITUDE (1000 FT)KC-10 Aircrew Training System

Driftdown

CH 4

W839-03 3-9 01 JUL 13 3.8 Cruise-Climb Segment

Figure 3-9. Cruise-Climb Segment.

This flight segment (Fig. 3-9) is started at bottom of dri ftdown. At this point, the

aircraft is at the bottom of driftdown altit ude at driftdown airspeed. The aircraft is leveled off and as the gross we ight is reduced by fuel c onsumption, the aircraft is

allowed to accelerate to 270 KIAS. This is the start of the cr uise-climb profile to

destination. GW 460 GW 380

10,000' GW 300

16,500'KC-10 Aircrew Training System

Driftdown

CH 4

W839-03 3-10 01 JUL 13 Figure 3-10. Maximum Continuous Thrust.KC-10 Aircrew Training System

Driftdown

CH 4

W839-03 3-11 01 JUL 13 3.9 N 1 Setting for Maximum Continuous Thrust

Figure 3-10 shows the chart for the Ma ximum Continuous Thrust setting for

driftdown. Note that the chart is enter ed with total air temperature as opposed to actual outside temperature. Also note that the altitude grids reverse at 36,089' until the top of the cert ified envelope is reached.

Now, look at the small engine bleed correction grid. The N 1 value is a function of total air temperature, but the bleed air correction is a function of pressure

altitude.

These power corrections are reflected in the driftdown altitude capability charts and graphs. The driftdown charts are bas ed on both air conditioning packs "Off" below 10,000 feet (See Bleed Correcti on "A") and one pack "On" above 10,000 feet. The altitude capability is also r educed by bleed loss for wing and engine anti ice "On" (See Bleed Correction "D").

Note that Bleed Correction "A" is a positive correction while Bleed Correction "B", "C", and "D" are negative.KC-10 Aircrew Training System

Driftdown

CH 4

W839-03 3-12 01 JUL 13 THIS PAGE INTENTIONALLY LEFT BLANKKC-10 Aircrew Training System

Driftdown

CH 4

W839-04 4-1 01 JUL 13 4.0 BASIS FOR TERRAIN CLEARANCE

Terrain clearance charts (Fig. 4-1) are based on driftdown from a maximum altitude of 29,000 feet and a maximum gross weight at start of driftdow n of 540,000 pounds.

If the actual top of driftdown is above 29,000 feet or the gross weight is above 540,000 pounds, the fuel burned, distance, and ti me to driftdown increase slightly. These increases are considered neg ligible and require no adjustments.

Another way to look at this is anytime the aircraft is above 29, 000 feet or above 540,000 pounds, consider the aircraft is alr eady at the maximum altitude and gross weight and compute the data based on that weight. (The aircraft will be at that altitude fairly rapidly).

Gross weight has the most influence on alti tude capability. If gr oss weight must be

reduced for terrain clearance and that val ue is less than 30,000 pounds, the dump time is negligible as far as time to bottom of driftdown is concerned. Fuel dump rates are calculated at approx imately 5,000 pounds per minute.

Wind has a dramatic effect on the driftdown procedure. Since the driftdown profile is primarily a function of time, the distance tr aveled toward the obstacle or terrain in a given amount of time is decreased with a headwind. This is why the terrain

clearance charts are entered with the distance to the critical terrain and the wind factor to determine the weight and altitude for terrain clearance.

4.1 Thrust

All driftdown information is based on Maximu m Continuous Thrust from one engine. MCT should be applied immedi ately upon the loss of the second engine and carried throughout the driftdown to in sure optimum performance. Lower thrust settings will severely degrade driftdown range and time.

4.2 Temperature

Data are presented from standard day to standard day plus fifteen degrees. This

reflects the flat rated Maximum Continuous Thrust output for that temperature range. Data are also provided for standard day plus twenty degrees.KC-10 Aircrew Training System

Driftdown

CH 4

W839-04 4-2 01 JUL 13 4.2.1 Terrain Clearance-Standard Day to Standard Day + 15

Figure 4-1. Terrain Clearance.KC-10 Aircrew Training System

Driftdown

CH 4

W839-04 4-3 01 JUL 13 4.3 Drag

All driftdown data are pres ented for a clean configuration. Any increase in drag degrades driftdown performance. Terra in clearance and driftdown altitude capabilities are reduced by 125 feet per unit of drag index, and fuel consumed during driftdown is increased by 100 pounds per unit of drag. These correction

factors are Noted on the applicable chart.

4.4 Anti-Ice

Engine and wing anti-ice systems use bleed ai r extracted from the engines. This

results in a reduction of avail able thrust output. This loss of thrust reduces driftdown performance and terrain clearance.

Bottom of driftdown altitude capabilities are reduced by 1,000 feet

.

Distance, time, and fuel used are not significantly affected.

4.5 Pressurization

If both wing engines are inoperat ive, the loss of their air conditioning systems will make pressurization impossible. The KC- 10 is designed as a "very tight ship", so the loss of pressurization will not be dramatic. Initially the aircraft will start to depressurize at approximately 1, 500 feet per minute. Once the checklist is initiated and the Avionics Override switch is placed to "Override", the rate of depressurization will decrease to approximately 800 feet per minute. This provides ample time to descend to the APU operational envelope, start the APU, and establish pneumatics to one air conditioning pack.

If pressurization cannot be maintained, the passengers have approximately 22 minutes of supplemental oxygen. The masks will automatically deploy at a cabin altitude of 14,000 feet and above.

If terrain or range are limiting , maintain the driftdown profile.

If terrain or range are not limiting , descend to be at least 13,000 feet (10,000 feet, if possible) within 22 minutes of the second engine failure.KC-10 Aircrew Training System

Driftdown

CH 4

W839-04 4-4 01 JUL 13 THIS PAGE INTENTIONALLY LEFT BLANKKC-10 Aircrew Training System

Driftdown

CH 4

W839-05 5-1 01 JUL 13 5.0 DRIFTDOWN PROCEDURES

As stated earlier in this workbook, drift down is the procedure utilized when cruise altitude can no longer be maintained due to the shut down of one or more engines. This segment will discuss dri ftdown procedures by illustrating five

scenarios.

1. Gross Weight, Range, and Terrain, Not Limiting

2. Gross Weight and Range are Limiting

3. Gross Weight and Terrain are Limiting

4. Endurance Range and Time are calculated

5. Typical Driftdow n ProfileKC-10 Aircrew Training System

Driftdown

CH 4

W839-05 5-2 01 JUL 13 5.0.1 Driftdown Altitude Capability

Figure 5-1. Driftdown Altitude Capability. MEA
4,600 ′

460 460 440 2,500 ′KC-10 Aircrew Training System

Driftdown

CH 4

W839-05 5-3 01 JUL 13 5.1 Gross Weight, Range or Terrain are Not Limiting, Driftdown (Profile) Not required.

Figure 5-2. Instantaneous Gross Weight.

Gross Weight .................................................................................... 460,000 lbs

Zero Fuel Weight .............................................................................. 360,000 lbs

Altitude .................................................................................... 8,000' Temperat ure .................................................................................... Standard Day One Engine Operat ing ...................................................................... Number 3

Advance the remaining throttle to MCT. Flaps, "Up". Speed, "Driftdown or Minimum Maneuver". Gear, "Up". Slats, "Retract". Minimum Safe Altitude, "Check". Minimum safe altitude 4, 600 ft. Fuel Dump, "Consider".

Check the altitude capability in Figure 5-1 for a inst antaneous gross weight of 460,000 lbs and find the maximum altitude to be 2,500 ft. Now find the maximum gross weight at 4,600 to be 4 40,000 lbs. Fuel Dump equa ls 20,000 lbs. This will require about four minutes.

Notice that the decision logic of the c hecklist (Figure 5-2) drives you to the
"DRIFTDOWN REQUIRED? NO" side of the checklist where the Instantaneous Gross Weight table is located. This table does not include fuel burned in driftdown, and mirrors the data prov ided in the chart in Figure 5-1.

This table will be used only when the full driftdown profile is not required. DRIFTDOWN REQUIRED

A LTITUDE CAPABILITY

NOTE

• ICE PROTECTION OFF.

• MAX CONTINUOUS THRUST.

• REDUCE ALTITUDE CAPABILITY BY 1,000 FEET FOR ENGINE PLUS WING

ANTI-ICE ON

. MIN SAFE ALTITUDE __________________CHECK (CP) FUEL DUMP ________________ ____CONSIDER (P,FE)KC-10 Aircrew Training System

Driftdown

CH 4

W839-05 5-4 01 JUL 13 Terrain Clearance Chart

Figure 5-3. Terrain Clearance. 420 4,500 ′

81KC-10 Aircrew Training System

Driftdown

CH 4

W839-05 5-5 01 JUL 13 Gross Weight, Range or Terrain Are Limiting, Dr iftdown Required

Figure 5-4. Altitude Ca pability after Driftdown.

Use the same conditions as before except assume the aircraft is flying at an altitude of 29,000 ft, three hundred nautical miles from destination. Again,
descend to the bottom of driftdow n maintaining driftdown speed.

The same checklist will apply except this time the "Driftdown Required" Logic will
be followed.

This chart in Figure 5-4 is a tabulated depi ction of the Terrain Clearance chart in Figure 5-3. Notice that Figure 5-3 is based on the actual weight of the aircraft at the time of the second engin e failure. The charted wei ght is based on burning off fuel during driftdown to be at a weight th at will allow a specific altitude to be

maintained.

Enter the Terrain Clearance chart in Figu re 5-3 with 460,000 lb s and read right to
the bottom of driftdown line. Find a bottom of driftdown altitude of 4,500 ft. Now, check the Tabulated Data in Figure 5- 4 and confirm that the altitudes are identical. Both yield an altitude of 4,500 ft.

Also note that the time and range to bo ttom of driftdown is 81 minutes and 420
nautical miles. Since the bottom of dr iftdown range exceeds the distance to destination, the driftdown pr ofile would be continued only to the point at which the descent and approach were initiated. MIN SAFE ALTITUDE ___________________CHECK (CP) FUEL DUMP CONSIDER________ ____CONSIDER (P,FE) DRIFTDOWN REQUIRED

REFER TO THE FOLLOWING CHART TO DETERM INE ALTITUDE CAPABILITY AFTER DRIFTDOWN, REFER TO 1c-10(k)A-1-1, SECTION X1 TO DETERMINE TERRAIN CLERANCE CAPABILITY.

NOTE

ICE PROTECTION OFF.

MAX CONTINUOUS THRUST.

REDUCE ALTITUDE CAPABILITY BY 1,000 FEET FOR ENGINE PLUS WING

ANTI-ICE ON.

VALID FOR START OF DRIFTEOWN ALTITUDES 29,000 FEET. ALTITUDE CAPABILITY AFTER DRIFTDOWN

GROSS WEIGHT

AT SECOND

ENGINE FAILURE (1,000lbs) AT DRIFTDOWN SPEED

TO STD + 15 ° C STD + 20 ° C

ALTITUDE (FT)

300 – –

320 – –

340

– – 360 12,000 11,600
380 10,300 10,000
400 9,000 8,400
420 8,000 6,600
440 6,200 4,700

460 4,500 2,500
480 2,600 –

500 – –KC-10 Aircrew Training System

Driftdown

CH 4

W839-05 5-6 01 JUL 13 Terrain Clearance

Figure 5-5. Terrain Clearance-Terrain Limiting. 150 396 DUMP

TOKC-10 Aircrew Training System

Driftdown

CH 4

W839-05 5-7 01 JUL 13 5.2 Gross Weight and Terrain are Limiting-Range is Not a Factor.

Given: Gross Weight .............................. 440, 000 lbs Temperature ............................... Standard Da y Plus 15 °

Zero Fuel Wei ght ........................ 350, 000 lbs

Headwind .................................... 50 Knots

Altitude ........................................ 29,000 ft Engines Oper ating ...................... One

Terrain ........................................ 12,400 ft AGL

Distance to Te rrain ..................... 150 NM

Enter the Terrain Clearance chart (Fi gure 5-5) with 150 NM, apply the 50 knot headwind, and find driftdown time to be 32 minutes.

From this point read up to the pressure altitude li ne of 11,700 ft (Geometric height of 12,400 corrected for plus 15 degrees non standard temperature). Read

a maximum start of driftdow n weight of 396,000 lbs. Present Gross Weight is
440,000 lbs. Immediat e fuel dump of 44,000 lbs is required.

The driftdown profile will now be continued until the terra in is cleared. At this point, the cruise climb segment will be flown to destination ending with a single engine approach and landing.KC-10 Aircrew Training System

Driftdown

CH 4

W839-05 5-8 01 JUL 13 Figure 5-6. Terrain Clearance. 480

445KC-10 Aircrew Training System

Driftdown

CH 4

W839-05 5-9 01 JUL 13 5.3 Gross Weight and Range Are Limiting Terrain is Not a Factor

Determine Time And Range

Gross Weight ................................................... 500, 000 lbs

Zero Fuel Wei ght ............................................. 310, 000 lbs

Altitude ................................................... 29,000 ft Temperature ................................................... St andard Day Engines Oper ating ........................................... One

Distance from Second E ngine Failure ............. 2,000 NM Fuel Required Over De stination ...................... 20,000 lbs

MCT Power Se t ............................................... 112% RPM

Initial Driftdown Speed ..................................... MACH 0.82/280 KIAS Established

Determine Altit ude Capability .......................... ZERO FEET Initially dump to 480,000 # ............................... Altitude Capability-2,600 ft

Minimum Safe Alti tude ..................................... 2,000 ft Zero Fuel Weight + Fuel Required .................. 330,000 lbs overhead Destination.

Enter the Terrain Clearance chart (Figure 5-6) with 480,000 lbs (a fter dump) at 29,000 ft and determine the distance to bottom of driftdown to be 445 NM.

Subtract the Driftdown distance from t he distance to destination of 2,000 NM and

find a distance from bottom of drift down to destination to be 1,555 NM.

The bottom of driftdown gross weight is 455,000 lbs (Initial Gross Weight 500,000 pounds. Initial Dump to 480,000 mi nus 25,000 lbs of fuel used during driftdown).

Now, take a look at Figure 5-7 on the next page.KC-10 Aircrew Training System

Driftdown

CH 4

W839-05 5-10 01 JUL 13 Figure 5-7. Bottom of Driftdown Altitude Capability. 2,600 ′

455KC-10 Aircrew Training System

Driftdown

CH 4

W839-05 5-11 01 JUL 13 5.4 Bottom of Driftdown Altitude Capability

Enter the chart in Figure 5- 7 with the predicted driftdown altitude of 2,600 ft and
confirm the bottom of driftdown gross weight to be 455,000 lbs.

Figure 5-8. Integrated Range and Time.

Now, enter the Integrated Range and Time chart (Fig. 5-8) with the bottom of driftdown gross weight of 455,000 lbs and find a reference distance of 350 NM.
Add the distance to destinat ion of 1,555 to obtain 1,905 miles. Now, enter with 1905 and find the gross weight over destinat ion to be 370,000 lbs. The required gross weight at destinat ion was 330,000 pounds. In this case you would be overhead destination with 40, 000 lbs of extra fuel. Now, find range endurance.

Enter Figure 5-8 with the zero fuel we ight of 310,000 lbs and find a reference distance of 3,300 NM. Now enter with the bottom of driftdown gross weight of 455,000 lbs and find a reference distanc e of 350 NM. 3,300 minus 350 equals 2,950 NM. This is your maximum range to dry tanks. Now, find endurance time.

Use the same procedures with the time line in Figure 5-8. Find that the total endurance time is 9.6 hours: (310,000 = 11 .2) minus (455,000 = 1.6). This is your maximum time to dry tanks.KC-10 Aircrew Training System

Driftdown

CH 4

W839-05 5-12 01 JUL 13 5.5 Typical Driftdown Profile

You have covered the terminology, c harts and procedures associated with driftdown. Now, as a review, take a l ook at a typical driftdown sequence. The

events are discussed without reference to actual "numbers" except where they are required for clarity.

Figure 5-9. Sequential Profile.

Figure 5-9 shows the events fr om the cruise altitude at which driftdown becomesnecessary because of the loss of two engines to the point at which the cruiseclimb segment is initiated at 10,000 ft. Figures 5-10 through 5-17 illustrate the sequence of events.KC-10 Aircrew Training System

Driftdown

CH 4

W839-05 5-13 01 JUL 13 5.5.1 At Cruise Altitude/Air speed/Two Engines Inoperative

Immediately increase the remaining eng ine to Maximum Continuous Thrust.

Maintain cruise altitude until the target airspeed of MACH 0.82 or 280 KIAS is reached. This is ample time for the Flight Engineer to compute a driftdown speed and bottom of driftdown altitude. 

### Figure 5-10. Cruise Altitude /Two Engines Inoperative.KC-10 Aircrew Training System

Driftdown

CH 4

W839-05 5-14 01 JUL 13 Figure 5-11. Start Driftdown.

Establish driftdown speed. Determine if f uel dump is required. Check terrain or minimum enroute altitude requirements. Select Semi-Auto on the Cabin

Pressurization Mode Switch and set 10,000 ft in the cabi n altitude set scale. Set

cabin rate of climb that wil l allow the cabin and the ai rcraft to reach 10,000 ft at the same time. Move the temperature se lector to full hot on the inoperative wing engine’s air conditioning pack. (Clo ses the ram air doors reducing drag)KC-10 Aircrew Training System

Driftdown

CH 4

W839-05 5-15 01 JUL 13 Start of Driftdown to 10,000 ft

Figure 5-12. Driftdown to 10,000 Feet.

Update driftdown speed at least each 5,00 0 feet. At 10,000 feet, the aircraft should be depressurized. Turn off the remaining pack and move the selector to

full hot to close its ram air inlet and exhaust doors. Recompute the N 1 setting for air conditioning "off". This will cause the rate of descent to flatten out.KC-10 Aircrew Training System

Driftdown

CH 4

W839-05 5-16 01 JUL 13 Figure 5-13. Level off at Bottom of Driftdown.

The aircraft rate of descent will tend to decrease or stop as the aircraft reaches the maximum altitude for singl e engine operation. Level off and allow the aircraft to accelerate to the cruise-climb airspeed of 270 KIAS.KC-10 Aircrew Training System

Driftdown

CH 4

W839-05 5-17 01 JUL 13 First Cruise-Climb Segment

Figure 5-14. First Cruise-Climb Segment.

Upon reaching 270 KIAS, allow the aircraft to climb as the fuel is consumed. This will be a very small rate of climb. Continue this procedure until an altitude of 10,000 ft is reached. 10,000KC-10 Aircrew Training System

Driftdown

CH 4

W839-05 5-18 01 JUL 13 Level Off at 10,000 ft

Figure 5-15. Level Off at 10,000 ft.

Upon reaching 10,000 ft, level off and throttle back to main tain 270 KIAS until a gross weight is achieved that will allo w cruise-climb with one air conditioning pack operating. This will require a burn off of approximately 14,000 lbs (See Cruise Climb Capability Chart in Figure. 3-8). 10,000'KC-10 Aircrew Training System

Driftdown

CH 4

W839-05 5-19 01 JUL 13 Second Cruise-Climb Segment

Figure 5-16. Second Cruise-Climb Segment.

When the fuel burn off is sufficient to allow operation with on e air conditioning pack "On", establish pressurization to ma intain a cabin altitude no higher than 10,000 ft. Recompute and re-establish MCT.KC-10 Aircrew Training System

Driftdown

CH 4

W839-05 5-20 01 JUL 13 Final Cruise-Climb Segment

Figure 5-17. Final Segment.

Once pressurization is established and MCT with one air conditioning pack "On" is set, continue the cruise-climb proc edure until destination is reached. Remember, this driftdown profile illust rates a typical driftdown sequence.

Unusual circumstances such as both wing engines out, passengers, and mission criticality may require majo r modifications to the prof ile. However, for most situations, all or part of this profile is used in all driftdown situations.KC-10 Aircrew Training System

Driftdown

Original

W839-06-WB 6-1 01 MAR 06 6.0 LESSON EXERCISE

Complete the following exer cise and return this workbook to your instructor.

1. Driftdown is defined as a forced desc ent resulting from the loss of one or more engines when operating abov e the maximum _______________ ceiling for the number of engines operating.

2. Driftdown is an integral par t of the _______________

________________ Emergency Checklist.

3. The "Driftdown Altitude Capabilit y" chart in the Performance Manual is based on the aircraft gross weight at the _______________ of driftdown.

4. The "Instantaneous Gross Weight" t abulated data table in the abbreviated checklist is based on the weight at the ________________ of the second engine failure.

5. The power setting for all driftdow n operations is

_________________

___________.

6. The KC-10 "Net Driftdown Perf ormance" is ______ _______ percent less than the predicted "Gross Dr iftdown Performance".

7. All driftdown performance charts are based on _____________ performance.

8. The driftdown speeds published in the flight manual are designed to provide the most _______________ fr om the top of driftdown.

9. Driftdown speed should be updated every ____________ feet.

10. Obstacles are depicted on terrain charts in _____________ heights above

sea level.

11. If the geometric height is correc ted for non-standard temperature, an altimeter setting of ___________ must be used.

12. The "Cruise Climb Altitude Capabilit y" chart is the maximum altitude that can be maintained with MCT power set on one engine at _________

KIAS.KC-10 Aircrew Training System

Driftdown

Original

W839-06-WB 6-2 01 MAR 06 13. The only difference between the "D riftdown Altitude Capability” and the "Cruise Climb Altitude Capability" chart is the ______________ on which

the chart is based.

14. Cruise Climb is a procedure where the aircraft is allowed to___________ as fuel is consumed. This proc edure provides the maximum __________

available.

15. The engine bleed correction grid on the N 1 Setting For Maximum

Continuous Thrust is a function of ________________________.

16. MCT is a function of ____________________ te mperature and

_________ ___________.

17. The Terrain Clearance Charts are based on a maximum gross weight of _____________ pounds and a maximum altitude of ______________

feet.

18. Fuel dump rates are normally calculated at __________ pounds per

minute.

19. Using a thrust setting lower than MCT during the driftdown profile will severely degrade driftdow n _____________ and _____________.

20. If anti-ice systems are r equired during driftdown, t he altitude capability is reduced by _____________ feet.

21. The "Altitude Capability After Dri ftdown" tabulated data is based on the

fuel burned dur ing ________________.

22. The Integrated Range and Time c hart is entered wit h ___________ gross weight and _____________ ____________ weight.

23. Range and time are based on flying a constant _________ KIAS to

destination.

24. The first target airspeed for driftdown is MACH ___________ or
_________ KIAS.

25. During driftdown, th e cabin pressurization control is placed in
___________ _________ and a cabin altitu de of _____________ feet is

selected.KC-10 Aircrew Training System

Driftdown

Original

W839-06-WB 6-3 01 MAR 06 26. Moving the air conditioning pack to full hot on the pack supplied by the inoperative engines closes the ______________________ _ door and reduces ____________.

27. At 10,000 feet, the ca bin should be ____ _____________. At this point, the remaining air conditioning pack is turned off and _________ power must be recomputed.

28. The aircraft rate of descent will tend to flatten out as the aircraft reaches the maximum altitude for single-engine operation. Level off at driftdown speed and allow the aircraft to accelerate to ___________KIAS.

29. When cruise climb speed is attained, allow the aircra ft to climb as fuel is

consumed until an altitude of ____________ feet is reached.

30. Upon reaching ___________ feet, thro ttle back to maintain _________ KIAS until the gross weight is ac hieved that will allow operation with _______ air conditioning pack "ON".

31. Establish pressurization to mainta in a cabin altitude of at least __________ feet.

32. Once pressurization is estab lished, re-compute

_____________________ thrust with one air condition ing pack on and maintain the cruise climb to

destination.

Note: Complete the following driftdown perfo rmance exercises, using the charts in this workbook or your Performance Manual.

33. Given: GW: 350,000 pounds. Find t he altitude driftdown capability for standard day conditions.

Answer: _______________feet.

34. Given: GW: 400,000 pounds. Find the driftdown speed for 30,000 Feet.

Answer: _______________ KIAS.

35. Given: Geometric Terrain at 14, 000 feet. Find the equivalent pressure altitude for standard day +20 ° C conditions.

Answer: _______________feet.KC-10 Aircrew Training System

Driftdown

Original

W839-06-WB 6-4 01 MAR 06 36. Given: GW: 350,000 pounds. Find t he standard day cruise-climb altitude capability.

Answer: ________________feet.

37. Given: TAT: Plus 10 Degrees C. Find the N 1 setting for Maximum Continuous Thrust at 10,000 feet.

Answer: __________________ percent.

38. What is the bleed correction for air conditioning packs "Off"?

Answer: ___________ _______ percent.

39. What is the bleed correction for wing and engine anti-ic e "On" with a wing engine inoperative?

Answer: __________________ percent.

Given: GW: 420,000 pounds. Altitude: 29,000 feet. Wind Factor: minus 50 Kts. Conditions: Standard Day. Use the Standard Day to Plus 15

chart to:

40. Find: Bottom of driftdown altitude. Answer: ________ feet.

41. Find: Fuel burned during dri ftdown. Answer: ___________ pounds.

42. Find: Time to driftdown. Answer: ______ minutes.

43. Find: Distance to bottom of driftd own. Answer:_________ Nautical Miles.

Given: Bottom of Driftdown GW: 400,000 pounds. Zero Fuel Weight: 320,000 pounds. Fuel Required over Destination: 20,000 pounds.

Distance to Destination: 1,180 NM. Standard Da y Conditions. Use the Integrated Range and Time Chart to:

44. Find: Fuel remaining at des tination. Answer: ___________pounds.

45. Find: Range to dry tanks. Answer: _________Nautical Miles.

46. Find: Time to dry tank s. Answer: _____________Hours.KC-10 Aircrew Training System

Driftdown

Original

W839-06-WB 6-5 01 MAR 06 THIS PAGE INTENTIONALLY LEFT BLANKKC-10 Aircrew Training System

Driftdown

Original

W839-06-WB 6-6 01 MAR 06 Lesson Exercise Answer Key

1. service 2. Single Engine Operation

3. bottom

4. instant
5. Maximum Continuous Thrust

6. 0.3

7. net 8. range (or NMPP) 9. 5,000 10. geometric

11. 29.92

12. 270 13. airspeed 14. climb/range (or NMPP) 15. pressure altitude 16. total temperature/pressure altitude 17. 540,000/29,000 18. 5,000 19. range/time 20. 1,000
21. driftdown 22. beginning/zero fuel

23. 270 24. 0.82/280 25. semi-auto/10,000 26. ram air/drag 27. depressurized/MCT

28. 270 29. 10,000 30. 10,000/270/one 31. 10,000
32. Maximum Continuous 33. 11,800

34. 255 35. 13,000 36. 11,100

37. 106.8

38. Plus 1.4

39. Minus 1.4 40. 8,000 41. 16,800

42. 70

43. 310 44. 22,050 45. 1,755

46. 5.6