TM 1-1510-223-10
7-8 Change 2
Obstacle Distance from Brake Release...10.71 nm
1. Obtain the accelerate-go distance to
50 feet AGL........5357 feet (0.88 nm).
2. Read the scheduled distance from the
HORIZONTAL DISTANCE FROM
REFERENCE ZERO TO THIRD SEG-
MENT
CLIMB
graph
(FLAPS
APPROACH)..................6.97 nm.
3. Add the results of steps 1 and 2 to
obtain total distance to start of third
segment climb, (0.88 nm + 6.97 nm)
= 7.85 nm.
4. Distance to obstacle from start of third
segment climb is obtained by subtract-
ing results of step 3 from 10.71 nm.
(10.71 - 7.85) = 2.86 nm.
5. Add to the obstacle height above the
aircraft at brake release any decrease
in aircraft altitude during the takeoff
resulting from a downhill runway gra-
dient.
The sum is the total height required to clear the ob-
stacle.
(1.9% gradient / 100) x 5357 ft = 101.8 feet = 102 feet
The total height required to clear the obstacle is: 600
ft + 102 ft = 702 feet.
6. Required climb gradient to clear ob-
stacle is obtained using the following
formula:
% Gradient = (RH) x (F) / (D)
Where:
RH = Required Height (in feet) above 500 feet
F = A units conversion factor of 0.0165
D = Distance (in nautical miles) to obstacle from start
of third segment
Therefore:
% Gradient = (702 - 500) (0.0165) / 2.86 = 1.1654% =
1.17%
7. Obtain (from the NET TAKE-OFF
FLIGHT PATH - THIRD SEGMENT
ONE-ENGINE INOPERATIVE graph)
the scheduled third segment net gradi-
ent of climb of 1.47%. Since this gradi-
ent exceeds the required gradient of
1.17%, the calculations indicate that
the obstacle will be cleared at a takeoff
weight of 16,000 pounds even if an
engine should fail at the most critical
takeoff point.
k. Climb - Two Engines. Enter the graphs at -4°C,
9000 feet pressure altitude, 15,500 pounds, and obtain
the following results:
Climb - Two Engines (FLAPS UP)......2119 ft/min
Climb Gradient...................................................5%
Climb - Two Engines (FLAPS APPROACH)..2031
ft/min
Climb Gradient................................................11.4%
l.
Climb - One Engine Inoperative. Enter the graph at
-4°C, 9000 feet pressure altitude, 15,500 pounds, and
obtain the following results.
Climb - One Engine Inoperative............264 ft/min
Climb Gradient.................................................1.4%
m. Flight Planning Example. The following calcula-
tions provide information for flight planning. Calculations
for flight time, block speed, and fuel requirements for the
proposed flight are detailed below.
NOTE
For example purposes, the differences between
MSL altitudes and pressure altitudes have been
ignored in MEA calculations.
(1) ISA conversion. Enter the graph at the condi-
tions indicated:
BIL
Pressure Altitude....................................3499 feet
FAT.................................................................15°C
ISA Condition.........................................ISA +7°C
BIL-CZI
Pressure Altitude.................................25,000 feet
FAT................................................................-40°C
ISA Condition..........................................ISA -6°C
CZI-CPR
Pressure Altitude.................................25,000 feet
FAT................................................................-30°C
ISA Condition.........................................ISA +5°C
