Priority Classification. Routine
a. All AGPUs used to support the AH-64D, Longbow Apache helicopter are being modified
by MWO 1-1730-229-50-2 to upgrade the 400 Hertz, AC, output and the gas turbine engine
performance. The upgraded AGPU has a new 48 KVA AC generator, a modified generator
control unit (GCU), a 250-amp transformer rectifier unit (TRU), a modified exhaust ejector, and
associated wiring changes. The upgraded AGPU has been assigned a new part number and
national stock number for tracking.
b. The purpose of this TB is to detail these changes and provide revised operation and
maintenance procedures for the P/N 83-360D AGPU until the appropriate changes to Technical
Manual TM 55-1730-229-12 are published. Required changes to repair parts and special tools
list contained in TM 55-1730-229-24P are also included.
Differences Between Part Numbers.
a. The primary hardware change incorporated by MWO 55-1730-229-50-2 is replacement
of the P/N 83-360A (formerly MEP-360A) generator, which has a combined AC and DC output,
with a larger capacity AC generator. The 83-360D generator has no DC output. An aircraft
(AH-64A) type, 400 Hertz to 28 VDC, transformer rectifier unit (TRU) is used on the 83-360D
to power the battery charger, the 60-Hertz inverter and to start or service DC aircraft.
b. The exhaust ejector assembly on the 83-360D has also been modified to reduce the
backpressure. This improves the GTE efficiency, thereby increasing shaft horsepower,
increasing the pneumatic output and reducing fuel consumption.
c. This reduction in exhaust backpressure has also allowed changes in surge control
operations. A continuous bleed of GTE compressor output has been eliminated on the 83-360D
and the setting of the pneumatic system switch no longer controls the function of the surge
Repair Parts Support.
a. Repair parts peculiar to the 83-360D that do not have NSNs assigned can be obtained
through the AMCOM Project OLR at Savannah, Georgia. The point of contact is:
Mr. Dale DeRoia, DSN 971-6869, commercial (912) 352-6869 or Mr. Ron Lewis, DSN
971-6297, commercial (912) 352-6297.
b. A listing of repair parts peculiar to the 83-360D is contained in paragraph 6, followed by
a narrative discussion on necessary changes to TM 55-1730-229-24P.
Changes to TM 55-1730-229-12.
a. Changes to the TM are addressed in narrative form, not always in the exact wording of a
manual change. Only those chapters, sections, paragraph, tables, or figures that are affected by
the upgrade are covered. For ease of reference to the affected area in the TM, the remaining
portion of this paragraph is numbered the same as the existing AGPU TM.