21-40-01
99M90
Page: 6-2
Issued: May 9, 2012
Rev. New
I-Series Combustion Heater
Owners Manual
6.1
Testing (cont’d)
B. Precautions
WARNING:
WHETHER THE HEATER IS INSTALLED OR REMOVED, MAKE SURE
THAT THE AREA IN AND AROUND THE AIRCRAFT, ROTORCRAFT, OR
SHOP IS SECURE AND THE TESTING AREA IS WELL VENTILATED.
MAKE SURE THAT ALL STAFF AND PERSONNEL ARE WARNED THAT
TESTING IS PROGRESS.
CARBON MONOXIDE FROM THE HEATER
EXHAUST AS WELL AS THE POTENTIAL OF UNCONTAINED FIRE MAY
CAUSE INJURY OR DEATH.
FAILURE TO OBSERVE THIS WARNING
MAY COMPROMISE THE COMPONENT OR THE APPLICATION IT IS USED
IN.
IMPROPER TESTING MAY RESULT IN DEATH, SERIOUS BODILY
INJURY, AND/OR SUBSTANTIAL PROPERTY DAMAGE.
It is imperative that regular maintenance be accomplished per this manual or the HET P/N
99M91 Overhaul & Maintenance manual and per the requirements of the applicable
aircraft/rotorcraft service manuals and publications.
Tests must be done by qualified
and competent persons.
In addition, observe the following precautions:
1. Disconnect the battery or any ground power source before connecting or
disconnecting test instruments (except voltmeter), or before removing or
replacing any unit. Accidental grounding or shorting of power from the battery
may cause severe damage to the test instruments, heater components, and/or
heater or airframe wiring.
2. If the heater is tested on an aircraft/rotorcraft to observe heater performance,
make sure that the area in and around the aircraft/rotorcraft is secure and the
testing area is well ventilated. Make sure that all staff and personnel are warned
that testing is progress.
3. If the heater is being tested on the bench and combustion will occur, be sure that
the heater is retained and secure before power and fuel are applied. Make sure
that the air inlet is clear and the exhaust has been routed to outside air without
leaks. Make sure the fuel source is well away from the heater or any ignition
sources. The fuel source must come from an approved fuel container.
6.2
Pressure Decay Test
Evaluation of the condition of the combustion chamber is a vital task in maintaining the combustion
heater until overhaul time is reached. It shall be made at the 500 hour inspection and each 500 hours
thereafter (or 60 months, the first to occur). The latest revision of applicable heater related service
publications must be reviewed and complied with if required in preparation for decay testing:
This test is intended to be accomplished while the heater is installed with a minimum of accessory
disconnection. When necessary or desired for convenience, the heater assembly may be removed
from the aircraft/rotorcraft to conduct the pressure decay test.
It is recommended but not required that the Pressure Decay Tester,
P/N PDT 285B or P/N PDT
286B be used for this test.