Boeing 737 - Service Difficulty Alert

AL 2004-04
22 June 2004

Nose Landing Gear Upper Drag Brace

Transport Canada has recently received two separate Service Difficulty Reports on the cracking of the nose gear upper drag brace, P/N 65-80051-18. (IPL 32-20-00-01) (This part has several alternative part numbers identified in the IPC.)

These cracks were found on a Daily Check and were reported to be quite obvious to the naked eye. The defects are approximately 1/4-inch in length and 1/8 inch in depth, and in the vicinity of the L/H gear door attachment point.

Time in service for the two cracked components was approximately 43,000 cycles and 48,000 cycles. The upper drag brace has a life limit of 75,000 to 90,000 cycles dependant on installation. (FAA Type Certificate Data Sheet A16WE). The Boeing MRB document requests a "Check" of this component at each "C-Check" or every 3,000 hours.


The SDR database contains several similar occurrences with a varied time in service of 12,000 to 60,000 hours.

As the failure of this part may result in an unsafe condition, Transport Canada strongly recommends a "detailed visual" inspection be carried out, at the operator's earliest convenience, to ensure the integrity of the upper drag brace assembly in the area of the gear door actuating lever attachment.

Similar defects or further occurrences of this nature are to be reported to Transport Canada, Continuing Airworthiness, Ottawa, via the Service Difficulty Reporting program.

For further information contact a Transport Canada Center, or Mr. Paul Jones, Continuing Airworthiness, Ottawa, telephone (613) 952-4431, facsimile (613) 996-9178 or e-mail

For Director, Aircraft Certification

B. Goyaniuk
Chief, Continuing Airworthiness

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