MD-11 Flight Crew Operations Manual
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Landing Gear and Brakes -
Description and Operation
Land.10.8
Brake Temperature Monitoring/Tire Pressure Indicating
(BTM/TPI)
General
The BTM/TPI system consists of a BTM/TPI computer in the Center Accessory
Compartment (CAC) and pressure and temperature sensors on the landing gear.
The system monitors tire pressures and individual brake temperatures. These
temperatures and pressures are displayed on the SD when the CONFIGURATION
page is selected with the CONFIG cue switch.
Abnormal tire pressures and temperatures are annunciated by EIS alerts.
A blanked out portion of the CONFIGURATION page tire/brake display indicates
a component failure in the system. The display of an individual tire or brake will
be blank if data for that tire or brake is not available.
The BTM/TPI computer interfaces with both Flight Management Computers
(FMC) and all 3 display electronic units (DEU). BTM/TPI faults are stored in the
CFDS.
Tire Pressures
Normal tire pressures are as follows:
• Main gear - 210 psi.
• Center gear - 176 psi.
• Nose gear - 180 psi.
If a tire pressure is below normal (11 percent below on ground, 21 percent below
in flight/landing), the level 1 alert TIRE PRES LO is displayed.
On any axle, if one tire pressure is too far below the other tire (15 percent below
on ground, 26 percent below in flight/landing) the level 1 alert TIRE DIFF PRES
is displayed.
If the pressure in any tire drops below 50 psi, the level 2 alert TIRE FAIL is
displayed. The TIRE FAIL voice warning is inhibited during takeoff (80 kts - 400
ft) and landing (100 ft - 80 kts).
ABS HIGH DECELERATION RATES
MODE DECEL RATE REMARKS
MIN 6.5 ft per sec2
Normal braking for most day to day operations.
Comfortable ride for passengers.
MED 9.0 ft per sec2
This braking should be used on short runways,
contaminated runways, or any time greater than
normal braking is required.
MAX N/A
This braking allows maximum antiskid braking for
the shortest stopping distance.
October 02, 2006
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