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KC-10 Aircrew Training System 

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KC-10 Aircrew Training System 

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TABLE OF CONTENTS 

1.0 INTRODUCTION ............................................................................................... 1-1 

2.0 OBJECTIVES .................................................................................................... 2-1 

3.0 TERMINOLOGY ................................................................................................ 3-1 

4.0 BASIS FOR TERRAIN CLEARANCE ................................................................ 4-1 

5.0 DRIFTDOWN PROCEDURES .......................................................................... 5-1 

6.0 LESSON EXERCISE ......................................................................................... 6-1 
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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 driftdown 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 loss of a single engine. Reasonable cruise 

altitudes, sufficient for all terrain clearance, can be maintained 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 profile where neither gross weight, terrain, or range are 

limiting factors. (Complete Profile not required) 

2. A driftdown profile where gross weight and terrain clearance are limiting 

and range is not a factor. (Driftdown Profile Required) 

3. A driftdown profile where gross weight and range are limiting and terrain 

is not a factor. (Driftdown Profile Required) 

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

5. Typical driftdown profile illustrated. 
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2.0 OBJECTIVES 

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

1. Identify terminology associated with Driftdown Performance Computations. 

2. Identify conditions effecting Driftdown Performance Computations. 

3. Compute Driftdown Performance Data. 
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3.0 TERMINOLOGY

3.1 Driftdown Profile

Figure 3-1. Driftdown Profile. 

Driftdown is a forced descent resulting from 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, Driftdown 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. Fuel 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 cruise-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

PROFILE
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Figure 3-2. Driftdown Altitude Capability.

Figure 3-2. Driftdown Altitude Capability.

6,600

420
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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. There is another identically constructed 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 ENGINE OPERATION Abbreviated Checklist. 

It is not used for terrain clearance driftdown computations. It is, however, used 

when the aircraft is operating on a single engine, but the driftdown profile is not

required. 

3.3 Instantaneous Gross Weight

Figure 3-3. Altitude Capability-Instantaneous Gross Weight.

Figure 3-3 is an extract of part of the SINGLE ENGINE OPERATION Checklist. 

Notice that the tabulated data exactly matches the information provided in Figure 

3-2. Also note that the 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 feet. This chart yields the following: 

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

INSTANTANEOUS ALTITUDE..........................................................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 CAPABILITY 
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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 altitude capability, and a 

five percent increase in fuel flow when compared to gross performance. 

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

Performance. 
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Figure 3-5. Driftdown Speed.
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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 published in the Driftdown Section of the 

Performance Manual (Fig. 3-5) and the Single Engine Operation Checklist (Fig. 

3-6). These speeds provide optimum driftdown performance. Deviations of plus 

or minus ten knots will result in negligible loss of performance. The Flight 

Engineer should update the speed periodically (every 5,000 feet). The Pilot uses 

the updated speeds to flatten out the descent profile thus improving range 

capability. The terrain clearance capability, time, and range are based on 

maintaining this speed to the bottom of driftdown. 
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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 driftdown scenarios start out above the transition altitude, 

your altimeter setting will be 29.92 and the 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 pressure height and geometric height diverge as a 

function of temperature. 
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3.7 Cruise Climb Altitude Capability

Figure 3-8. Cruise Climb Capability.

This chart (Fig. 3-8) provides data to calculate the maximum altitude that can be 

maintained with one engine operating at Maximum Continuous Thrust while 

maintaining 270 KIAS. During Cruise Climb, the aircraft is allowed to climb as 

the gross weight is reduced by fuel consumption. The resulting rate of climb will 

be slight, and will result in the absolute maximum nautical miles per pound of fuel 

expended. All charted performance 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 instead 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 CAPABILITY

PRESSURE ALTITUDE (1000 FT) 
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3.8 Cruise-Climb Segment

Figure 3-9. Cruise-Climb Segment.

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

aircraft is at the bottom of driftdown altitude at driftdown airspeed. The aircraft is 

leveled off and as the gross weight is reduced by fuel consumption, the aircraft is 

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

destination. 

GW 460

GW 380

10,000'

GW 300

16,500'
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Figure 3-10. Maximum Continuous Thrust.
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3.9 N1 Setting for Maximum Continuous Thrust 

Figure 3-10 shows the chart for the Maximum Continuous Thrust setting for 

driftdown. Note that the chart is entered 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 certified envelope is reached. 

Now, look at the small engine bleed correction grid. The N1 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 based on both air conditioning packs "Off" 

below 10,000 feet (See Bleed Correction "A") and one pack "On" above 10,000 

feet. The altitude capability is also reduced 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. 

 
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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 driftdown 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 time to driftdown increase slightly. 

These increases are considered negligible 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 already 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 altitude capability. If gross weight must be 

reduced for terrain clearance and that value 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 approximately 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 traveled 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 Maximum Continuous Thrust from one engine. 

 MCT should be applied immediately upon the loss of the second engine and carried 

throughout the driftdown to insure 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. 
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4.2.1 Terrain Clearance-Standard Day to Standard Day + 15 

Figure 4-1. Terrain Clearance. 
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4.3 Drag

All driftdown data are presented for a clean configuration. Any increase in drag 

degrades driftdown performance. Terrain 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 air extracted from the engines. This 

results in a reduction of available 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 inoperative, 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. 
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5.0 DRIFTDOWN PROCEDURES 

As stated earlier in this workbook, driftdown 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 driftdown 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 Driftdown Profile 
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5.0.1 Driftdown Altitude Capability

 Figure 5-1. Driftdown Altitude Capability.

 MEA 

4,600′

460 

440 460 

2,500′
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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' 

Temperature .................................................................................... Standard Day 

One Engine Operating ...................................................................... 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 instantaneous 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 440,000 lbs. Fuel Dump equals 20,000 lbs. This will 

require about four minutes. 

Notice that the decision logic of the checklist (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 provided in the chart in Figure 5-1. 

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

DRIFTDOWN REQUIRED 

ALTITUDE 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)
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Terrain Clearance Chart 

Figure 5-3. Terrain Clearance. 

420 

4,500′

81 
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Gross Weight, Range or Terrain Are Limiting, Driftdown Required

Figure 5-4. Altitude Capability 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 driftdown 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 depiction 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 engine failure. The charted weight is based on burning off 

fuel during driftdown to be at a weight that will allow a specific altitude to be 

maintained. 

Enter the Terrain Clearance chart in Figure 5-3 with 460,000 lbs 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 bottom of driftdown is 81 minutes and 420 

nautical miles. Since the bottom of driftdown range exceeds the distance to 

destination, the driftdown profile 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 DETERMINE 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 – – 

 
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Terrain Clearance

Figure 5-5. Terrain Clearance-Terrain Limiting.

150 

396 

DUMP 

TO 
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5.2 Gross Weight and Terrain are Limiting-Range is Not a Factor.

Given: 

Gross Weight .............................. 440,000 lbs 

Temperature ............................... Standard Day Plus 15°

Zero Fuel Weight ........................ 350,000 lbs 

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

Altitude ........................................ 29,000 ft 

Engines Operating ...................... One 

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

Distance to Terrain ..................... 150 NM 

Enter the Terrain Clearance chart (Figure 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 line of 11,700 ft (Geometric 

height of 12,400 corrected for plus 15 degrees non standard temperature). Read 

a maximum start of driftdown weight of 396,000 lbs. Present Gross Weight is 

440,000 lbs. Immediate fuel dump of 44,000 lbs is required. 

The driftdown profile will now be continued until the terrain is cleared. At this 

point, the cruise climb segment will be flown to destination ending with a single 

engine approach and landing. 
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Figure 5-6. Terrain Clearance.

480 

445 
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5.3 Gross Weight and Range Are Limiting Terrain is Not a Factor

Determine Time And Range

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

Zero Fuel Weight ............................................. 310,000 lbs 

Altitude ................................................... 29,000 ft 

Temperature ................................................... Standard Day 

Engines Operating ........................................... One 

Distance from Second Engine Failure ............. 2,000 NM 

Fuel Required Over Destination ...................... 20,000 lbs 

MCT Power Set ............................................... 112% RPM 

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

Determine Altitude Capability .......................... ZERO FEET

Initially dump to 480,000 # ............................... Altitude Capability-2,600 ft 

Minimum Safe Altitude ..................................... 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 (after dump) at 

 29,000 ft and determine the distance to bottom of driftdown to be 445 NM. 

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

find a distance from bottom of driftdown 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 minus 25,000 lbs of fuel used during 

driftdown). 

Now, take a look at Figure 5-7 on the next page. 
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Figure 5-7. Bottom of Driftdown Altitude Capability.

2,600′

 455 
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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 destination of 1,555 to obtain 1,905 miles. Now, enter with 

1905 and find the gross weight over destination to be 370,000 lbs. The required 

gross weight at destination 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 weight 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 distance 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. 
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5.5 Typical Driftdown Profile

You have covered the terminology, charts and procedures associated with 

driftdown. Now, as a review, take a look 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 from the cruise altitude at which driftdown becomes 

necessary 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. 
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5.5.1 At Cruise Altitude/Airspeed/Two Engines Inoperative

Immediately increase the remaining engine 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. 
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Figure 5-11. Start Driftdown. 

Establish driftdown speed. Determine if fuel 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 cabin altitude set scale. Set 

cabin rate of climb that will allow the cabin and the aircraft to reach 10,000 ft at 

the same time. Move the temperature selector to full hot on the inoperative wing 

engine’s air conditioning pack. (Closes the ram air doors reducing drag) 
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Start of Driftdown to 10,000 ft 

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

Update driftdown speed at least each 5,000 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 N1 setting for 

air conditioning "off". This will cause the rate of descent to flatten out. 
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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 single engine operation. Level off and allow the aircraft 

to accelerate to the cruise-climb airspeed of 270 KIAS. 
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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. 

10,000
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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 maintain 270 KIAS until a 

gross weight is achieved that will allow 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'
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Second Cruise-Climb Segment 

Figure 5-16. Second Cruise-Climb Segment. 

When the fuel burn off is sufficient to allow operation with one air conditioning 

pack "On", establish pressurization to maintain a cabin altitude no higher than 

10,000 ft. Recompute and re-establish MCT. 
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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 procedure until destination is reached. 

Remember, this driftdown profile illustrates a typical driftdown sequence. 

Unusual circumstances such as both wing engines out, passengers, and mission 

criticality may require major modifications to the profile. However, for most 

situations, all or part of this profile is used in all driftdown situations. 
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6.0 LESSON EXERCISE

Complete the following exercise and return this workbook to your instructor. 

1. Driftdown is defined as a forced descent resulting from the loss of one or 

more engines when operating above the maximum _______________ 

ceiling for the number of engines operating. 

2. Driftdown is an integral part of the _______________________________ 

Emergency Checklist. 

3. The "Driftdown Altitude Capability" chart in the Performance Manual is 

based on the aircraft gross weight at the _______________ of driftdown. 

4. The "Instantaneous Gross Weight" tabulated data table in the abbreviated 

checklist is based on the weight at the ________________ of the second 

engine failure. 

5. The power setting for all driftdown operations is _________________ 

___________. 

6. The KC-10 "Net Driftdown Performance" is _____________ percent less 

than the predicted "Gross Driftdown 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 _______________ from 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 corrected for non-standard temperature, an 

altimeter setting of ___________ must be used. 

12. The "Cruise Climb Altitude Capability" chart is the maximum altitude that 

can be maintained with MCT power set on one engine at _________ 

KIAS. 
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13. The only difference between the "Driftdown 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 procedure provides the maximum __________ 

available. 

15. The engine bleed correction grid on the N1 Setting For Maximum 

Continuous Thrust is a function of ________________________. 

16. MCT is a function of ____________________ temperature 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 driftdown _____________ and _____________. 

20. If anti-ice systems are required during driftdown, the altitude capability is 

reduced by _____________ feet. 

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

fuel burned during ________________. 

22. The Integrated Range and Time chart is entered with ___________ 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, the cabin pressurization control is placed in 

___________ _________ and a cabin altitude of _____________ feet is 

selected. 
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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 cabin 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 aircraft to climb as fuel is 

consumed until an altitude of ____________ feet is reached. 

30. Upon reaching ___________ feet, throttle back to maintain _________ 

KIAS until the gross weight is achieved that will allow operation with 

_______ air conditioning pack "ON". 

31. Establish pressurization to maintain a cabin altitude of at least 

__________ feet. 

32. Once pressurization is established, re-compute _____________________ 

thrust with one air conditioning pack on and maintain the cruise climb to 

destination. 

Note: Complete the following driftdown performance exercises, using the charts in 

this workbook or your Performance Manual. 

33. Given: GW: 350,000 pounds. Find the 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. 
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36. Given: GW: 350,000 pounds. Find the standard day cruise-climb altitude 

capability. 

Answer: ________________feet. 

37. Given: TAT: Plus 10 Degrees C. Find the N1 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-ice "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 driftdown. Answer: ___________ pounds. 

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

43. Find: Distance to bottom of driftdown. 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 Day Conditions. Use the 

Integrated Range and Time Chart to: 

44. Find: Fuel remaining at destination. Answer: ___________pounds. 

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

46. Find: Time to dry tanks. Answer: _____________Hours. 
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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