99M90
21-40-01
Page: 5-1
Rev. New
Issued: May 9, 2012
I-Series Combustion Heater
Owners Manual
Chapter 5
CHECK
5.0
General
This chapter calls out the various checks and inspections needed to assure reliable and safe
operation of the combustion heater while in service.
It is the owners responsibility to observe
and understand the task and the time it occurs.
These required checks are listed in hours
time in service (TIS) or calendar time whichever is applicable. Some checks are one time
initial and others are recurring. Refer to the appropriate chapter as required for the specific
check in this manual or in the Overhaul & Maintenance manual P/N 99M91. Use only one method
to determine TIS for inspection and maintenance (actual heater Hobbs meter time
or
calculation
from flight time)
never use both
. These Checks must be accomplished by properly licensed
mechanics or repairmen experienced in aircraft/rotorcraft heating systems. Owners performing
an annual inspection should note “the first to occur” is the TIS requirement which may come
prior to or after the annual inspection calender time is reached.
5.1
Preflight and/or Daily Inspection Checks
(all heaters)
1.
Inspect the ventilating air inlet scoop, combustion air inlet scoop, exhaust outlet and fuel
drain for possible obstructions. Make sure that all of these openings are clear of any
restrictions and that no damage has occurred to air scoop protrusions.
2.
During preflight inspections look in the area of the combustion heater exhaust tube for large
or unusual accumulations of soot on the skin of the aircraft. Soot accumulates are caused by
the heater burning at a fuel "rich" condition.
5.2
Operational
Check (Typical Heater)
An operational check should be performed prior to commencing any inspection interval or prior
to any unscheduled maintenance to help determine the heater condition.
1.
Place the "MASTER SWITCH" in the "ON" (or "HEAT") position. The ventilating air blower
and combustion air blower should operate and the red "HEATER FAILURE LIGHT" should
be energized.
Always refer to the aircraft AFM or POH to assure proper operation.
2.
Operate both the combustion air blower and ventilating air blower and check each for
unusual current draw, noise or vibrations. Refer to Table 3.1 for troubleshooting and for
recommended maintenance.
3.
To proceed with the operational check, follow Chapter 2, para. 2.2 entitled "Operating
Procedure". This procedure should be repeated several times or as needed.
5.3
Periodic Inspection Checks
Note:
As many B-Series combustion heaters have been upgraded
to I-Series heaters, certain publications previously issued
may still be relevant. If you heater has been upgraded to
I-Series heater, you should reference the latest revisions of the
following publications to assure compliance. SB A-101 Rev G,
SB A-104 Rev. B, SB A-107A, SB A-108, and SB A-110B.)
10 Hours time in service
(one time overhauled, rebuilt, or new).
Perform an initial check of the heater assembly. Gain access to the heater and check the
security of electrical connectors and connections at the terminal strip, ignition leads and
spark plug, all inlet and outlet air connections, and fuel line. Check the exhaust tube for
condition and interference with structure. Check the drain line for obstructions.
