TM 55-1510-220-10
7-3. Pressure Altitude.
To determine the approximate pressure altitude at origin
and destination airports, add 1000 feet to field elevation
for each 1.00 in. Hg that the reported altimeter setting
value is below 29.92 in. Hg, and subtract 1000 feet for
each 1.00 in. Hg above 29.92 in. Hg. Always subtract
the reported altimeter setting from 29.92 in. Hg, then
multiply the answer by 1000 to find the difference in feet
between field elevation and pressure altitude.
Pressure Altitude at DEN:
29.92 in. Hg - 29.82 in. Hg = 0.10
0.10 x 1000 feet = 100 feet
The pressure altitude at DEN is 100 feet above field
elevation.
Pressure altitude at DEN = 5333 + 100 =5433 feet.
Pressure altitude at RNO:
29.92 in. Hg - 29.60 in. Hg = 0.32
0.32 x 1000 feet = 320 feet
The pressure altitude at RNO is 320 feet above field
elevation.
Pressure altitude at RNO = 4412 + 320 = 4732 feet.
7-4. Performance Example.
Maximum takeoff weight (from LIMITATIONS Section) =
15,000 pounds
NOTE
For this example, the effect of
paragraph 7-17 has not been
shown.
7-5. Maximum Takeoff Weight Permitted By Enroute
Climb Requirement.
Enter the graph at 5433 feet takeoff field pressure
altitude to 280C takeoff FAT:
Maximum Allowable Takeoff
Weight .................................. 14,090 pounds
The maximum takeoff weight permitted by the Enroute
Climb Requirement graph is the only operating limitation
required
to
meet
applicable
FAR
requirements.
Information has been presented, however, to determine
the takeoff weight, field requirements, and takeoff flight
path assuming an engine failure occurs during the
takeoff procedure. The following illustrates the use of
these charts.
7-6. Takeoff Weight To Achieve Positive One-
Engine-Inoperative Climb At Liftoff (Flaps 0%).
Enter the graph at 5433 feet to 28°C, to determine a the
maximum weight at which the accelerate-go procedure
should be attempted.
Maximum Accelerate-Go
Weight .................................. 12,100 pounds
7-7. Accelerate-Stop (Flaps 0%).
Enter the Accelerate-Stop graph at 280C, 5433 feet
pressure altitude, 12,100 pounds, and 10 knots head
wind component:
Accelerate-Stop Distance .................... 5100 feet
Takeoff Decision Speed ......................101 knots
7-8. Take-Off Distance (Flaps 0%).
Enter the graph at 280C, 5433 feet pressure altitude,
12,100 pounds, and 10 knots head wind component:
Ground Roll...................................... 3280 feet X
Total Distance Over 50-foot
Obstacle ....................................... 5000 feet
Take-off Speed:
At Rotation....................................101 knots
At 50 Feet .....................................118 knots
7-9. Takeoff Flight Path Example.
The following example assumes the aircraft is loaded so
that takeoff weight is 10,000 pounds.
7-10. Accelerate-Go Distance Over 50-Foot Obstacle
(Flaps 0%).
Enter the graph at 280C, 5433 feet pressure altitude,
10,000 pounds, and 10 knots head wind component:
Total Distance Over 50-foot
Obstacle ....................................... 7800 feet
Speed at Rotation (VR ...........................95 knots
Speed at 35 Feet Above Runway
(Climb Speed)...............................109 knots
7-2
