Aircraft
Certification Service Washington, DC U.S. Department of Transportation Federal Aviation Administration
NM-11-23
March 15, 2011
This is information only. Recommendations
aren’t mandatory.
Introduction
This Special Airworthiness Information Bulletin (SAIB) advises
registered owners and operators of The Boeing Company Model 767-400ER
airplanes of an airworthiness concern regarding the inner bore of the
main landing gear (MLG) truck beam.
Background
A recent incident occurred during taxi out for flight on a Model
767-400ER airplane, which resulted in fracture of a MLG truck beam. The
fracture occurred aft of the pivot joint and resulted in partial
collapse of the MLG. (It has been determined that this incident is not
related to the truck beam pivot joint.) This airplane was in-service
for nine years and had accumulated 40,581 total flight hours and 6,062
total flight cycles at the time of the incident. Preliminary data
revealed corrosion damage in the inner diameter of the truck beam, and
the aft drain hole was blocked and not draining properly. Overhaul of
certain other Model 767-400ER airplanes having this MLG truck beam
revealed two additional incidents of corrosion damage and pitting in
the same area where the fracture was found. This type of heavy,
localized corrosion has not been reported on any additional Model 767
airplanes having this MLG truck beam.
Boeing has issued service information to provide operators with
guidelines for reapplying the fillet seal around the MLG forward tow
fittings, inspecting the aft drain passages for blockage, and cleaning
of the MLG drain passage if necessary. The service information also
provides guidelines for inspecting the inside diameter of the MLG truck
beam for corrosion and damage to the primer, and applicable corrective
actions.
At this time, the airworthiness concern is not an unsafe condition that
would warrant Airworthiness Directive (AD) action under Title 14 of the
Code of Federal Regulations (14 CFR) Part 39.
Recommendations
The FAA recommends that all owners and operators of Model 767-400ER
airplanes comply with the actions outlined in Boeing Alert Service
Bulletin 767-32A0225, dated January 6, 2011.
Boeing Commercial Airplanes, Attention: Data & Services Management,
P. O. Box 3707, MC 2H-65, Seattle, Washington 98124-2207; phone:
206-544-5000, extension 1, fax: 206-766-5680; e-mail:
me.boecom@boeing.com; Internet https://www.myboeingfleet.com.