DEPARTMENT OF THE ARMY TECHNICAL BULLETIN
ENGINE VlBRATION SCREENING AND RECURRING
INSPECTION FOR ALL AH-1 SERIES AIRCRAFT WITH
T53-L-703 ENGINE (P/N 1-000-060-23) INSTALLED
Headquarters, Department of the Army, Washington, D. C.
28 July 1998
DISTRIBUTION STATEMENT A: Approved for public release; distribution is unlimited.
THIS PUBLICATION IS EFFECTIVE UNTIL RESCINDED OR
1. Priority Classification. URGENT
See AR 95-1, paragraph 6-6.a., for noncompliance authority of major
a. Aircraft in Use. Upon receipt of this TB, change the condition status symbol of the cited aircraft
to a Circled Red X. The Circled Red X entry shall state "T53-L-700 Engine N2 vibration inspection
procedures required IAW TB 1-2840-229-20-17 (SOF AH-1-98-01)." Enter a Red Dash status symbol.
The entry shall state "Commander and flight crew member review of risk mitigation measures lAW TB
1-2840-229-20-17 (SOF AH-1-98-01) required prior to flight." This is a recurring daily entry. If the engine
passes the vibration inspection per paragraph 8. of this TB, clear the Circled Red X status symbol and
release the aircraft for flight. If the engine fails the vibration inspection, change the aircraft status symbol to
a Red X. lnspect the aircraft as soon as practical, but not later than the task/inspection suspense date.
Change the aircraft symbol to a Red X for aircraft not inspected by this date. While on a Circled Red
X, continue to report the aircraft as fully mission capable (FMC).
b. Aircraft In Depot Maintenance. Aircraft will not be issued until compliance with this TB has been
c. Aircraft Undergoing Maintenance. Aircraft will not be released until compliance with this TB has
*This TB supersedes USAAMCOM Safety of Flight (SOF) Message AH-1-98-01, 242118Z, JUN 98.