Studi Kasus No Bleed pada APU Pesawat Boeing 737-800

Abstract

Auxillary Power Unit (APU) is small gas turbine engine that serves as pneumatic and electrical supply. Pneumatic supply originates from bleed air system in APU. Pneumatic supply by APU is used for main engine start, air conditioning, and pressurization. According to the pilot's report, one of the problems that often occur in APU was no APU bleed that could be seen from the absence of air pressure indicator in the cockpit, hence APU was unable to supply pneumatic for aircraft. As a consequence, an analysis was conducted to find out the cause and how to resolve cases of no APU bleed. The methods used were literature studies, observations, and consultations. The data was then analyzed using fishbone diagrams to identify and find the cause of no APU bleed cases. Based on the results of the analysis, no APU bleed can occur due to three main factors, consisting of wiring damage, bleed air valve, and delta pressure sensor. These factors caused starting engine process to be hampered. In order to overcome this problem, inspection can be done on APU wire harness, removal delta pressure sensor, and removal of bleed air valve