Abstract :
The air data system on the Boeing 737 Classic consists of an air data
instrument and two air data computers. Which are air data instruments are mach /
airspeed indicator, altimeter, and vertical speed indicator. The combination of a
pneumatic altimeter and an airspeed indicator provides a standby indicator. The
value of the computed airspeed and mach number will be displayed on the mach /
airspeed indicator combination of pitot static air pressure data processed by
computer data. This system has various problems. One of the problems is when the
mach indicator doesn't show the right result.
Troubleshooting is needed to solve the problems with the above Air data
system. The way to solve the problem when the mach indicator does not show the
right results on the Boeing 737 Classic is starting by performing an operational test
on the Air data system. There are two ways to perform operational tests on the Air
data system, namely Bite test and System test.
After doing this checking, a problem was found with the mach indicator.
After the Operational Test of the Air Data System on the Boeing 737 Classic aircraft
and it was found that the mach indicator was damaged, we had to carry out further
tests. The tests carried out are in the form of testing on the Mach indicator case,
airspeed capsule, pointer needle, and finally the accuracy of the airspeed. And
found a problem with the mach indicator case.
Therefore, according to the Component Maintenance Manual, the way to
troubleshoot this problem is to replace the mach indicator case with a serviceable
one. After replacing the mach indicator case, it is required to carry out the
operational test again on the Air data system. At the time of the operational test,
the needle on the mach indicator can operate normally and according to the
provisions. This shows the system and components have returned to a serviceable
state and can be used again.