TB 1--1520--237--20--219
(a) Same as para 1a.
(b) Those aircraft that have a DD 250 and are at Sikorsky will be inspected prior to ferry to
final designation.
e.
Maintenance Trainers (Category A, and B). Same as para 1a.
f.
Component/Parts in Stock at All Levels (Depot and Others) Including War Reserves. N/A.
g.
Component/Parts In Work (Depot Levels and Others). N/A.
2. Task/Inspection Suspense Date. Within the next 10 flight hours but NLT 31 May 2000 and report IAW
3.
Reporting Compliance Suspense Date. Report compliance IAW para 14a NLT 7 June 2000.
4.
Summary of the Problem.
a. Modification Work Order (MWO) 1--1520--237--50--66 is being applied to all H--60 aircraft with tail
numbers 77--22715 through 90--26367. Subsequent numbered aircraft had the Modification applied during
production and are not effected by this TB. During scheduled replacement of the engine fire extinguisher car-
tridges on a UH--60 aircraft, it was discovered that the fire extinguisher system was mis--wired. The wiring
for the no. 1 engine reserve squib was connected to the no. 2 engine primary squib, and the wiring for the
no. 2 engine primary squib was connected to the no. 1 engine reserve squib. A subsequent survey of fifteen
additional aircraft at various locations found that on one aircraft, the wiring was connected correctly but misla-
beled, marking it appear to be mis--wired when inspected visually. These conditions pose and obvious safety
risk. Attempting to activate the fire extinguisher system for one engine would actually result in the firing of
the extinguisher for the other engine. Mislabeling of wire bundles is also a concern as it could lead to inadver-
tent mis--wiring of the system during future maintenance operations.
b.
For manpower/downtime and funding impacts, see para 12.
c.
The purpose of this TB is to:
(1) Inspect the fire extinguisher wiring in order to identify all instances of misrouting and/or misla-
beling of wires.
(2) Perform an electrical continuity check of the fire extinguisher wire assembly.
5.
End Items to be inspected . All H--60 series aircraft, tail numbers 77--22715 through 90--26367.
6.
Assembly Components to be Inspected.
NOMENCLATURE
PART NUMBER
NATIONAL STOCK NUMBER
HARN ASSEMBLY, TRNSN RH
70552--03100--041
NA
HARN ASSEMBLY, TRNSN RH
70552--03100--042
NA
HARN ASSEMBLY, TRNSN RH
70552--03100--043
NA
7.
Parts to be Inspected . N/A.
8.
Inspection Procedures.
a. For all H--60 series aircraft with tail numbers 77--22715 through 90--26367, inspect the historical re-
cords (DA Form 2408--5) to determine if the aircraft has been modified in accordance with MWO
1--1520--237--50--66.
(1) If modified IAW MWO 1--1520--237--50--66, proceed to para 8b.
(2) For aircraft that have not been modified IAW MWO 1--1520--237--50--66, the inspection is
complete. The red horizontal dash//--// status symbol will be cleared and compliance with this message and
TB 1--1520--237--20--219 will be noted.
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