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D6-27370-866-EGP B-24 Page 1 of 2
CoversFile HighlightInflight Eleva tor Tab VibrationEGP-24
Flight Crew Operations Manual Bulletin
for
Egyptair
Number: EGP-24
IssueDate: March 26, 2010
Subject: Inflight Elevator Tab Vibration
Reason: This bulletin informs 737NG flight crews of the potential for elevator
tab vibration that may lead to significant structural damage.
THE FOLLOWING PROCEDURE AND/OR INFORMATION IS EFFECTIVE UPON RECEIPT
Background Information
Boeing has recently received a report from an operator that the failure of the aft
attach lugs on the left elevator tab control mechanism resulted in unwanted
elevator vibration during flight. The flight crew diverted from the intended route
and made an uneventful landing.
Investigation revealed that the fractured aft attach lugs on the elevator tab control
mechanism allowed free-play of the aft end of the mechanism, which in turn
allowed movement of the forward end of the elevator tab control rods. The result
of this condition was unexpected vibration of the elevator during flight.
Flight crews should be aware that there are many causes of airframe vibration,
including free-play in movable surfaces, system or engine malfunctions, and
environmental factors. Elevator tab vibration can occur during any phase of flight
and is characterized as a clearly noticeable moderate to severe vertical motion in
the flight deck and aft cabin. This vibration is characterized as a low frequency
vertical vibration in which motion of items attached to airplane structure, such as
sun visors, may be noticeable. In some cases, pilots have reported feeling
vibration in the control column and rudder pedals as this vertical motion is
transmitted through the structure and cables to the controls. If the cause of the
vibration is suspected to be due to empennage control surfaces, the discrepancy
should be corrected prior to further revenue flight.
The Boeing Company
Seattle, Washington 98124-2207
Information in this bulletin is recommended by The Boeing Company, but may not be FAA approved
at the time of writing. In the event of conflict with the FAA approved Airplane Flight Manual
(AFM), the AFM shall supersede. The Boeing Company regards the information or procedures
described herein as having a direct or indirect bearing on the safe operation of this model airplane.
September 24, 2015
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