SAIB ANM-99-31

SPECIAL

AIRWORTHINESS

INFORMATION

BULLETIN

REGULATORY SUPPORT DIVISION P.O. BOX 26460 OKLAHOMA CITY, OKLAHOMA 73125-0460

U.S. Department of Transportation Federal Aviation Administration

No. ANM-99-31 July 12, 1999

SAIB’s are posted on the internet at http://av-info.faa.gov This is issued for informational purposes only and any recommendation for corrective action is not mandatory.

Introduction:

The purpose of this Special Airworthiness Informa tion Bulletin (SAIB) is to inform registered owners/operators of Consolidated-Vult ee 28-5ACF, PBY-5, PBY-5A, Army OA-10, OA-10A, RCAF PBY-5A and RCAF 28-5AMC aircraft of the fa ilure of a nose gear bay door torque tube.

PBY-6A aircraft may also be affected.

Background:

The United Kingdom Aircraft Accident Investiga tion Board (AAIB) sent a safety recommendation report to FAA based on their investigation of an accident of a Consolidated Vultee Model 28-5ACF aircraft. The aircraft had been on the water for several seconds during a touch and go landing.

AAIB found that the left hand nos e gear bay door torque tube failed allowing dynamic water pressure loads to collapse the nose gear bay door s and directly impact the nose gear bay aft bulkhead and roof bulkhead resulting in failure of both bulkheads. The aircraft yawed violently to the left, filled with water and decelerated rapi dly. During the evacuation of 14 passengers and 4 crew the aircraft pitched forward trapping two passengers resulting in their death by drowning.

The failure of the left torque tube appeared to be the result of severe corrosion of the internal surface of the tube due to the presence of water ove r a long period of time. The ends of the tube were closed off by the insertion of two cork- like plugs (bungs). The location of the corrosion within the tube was consistent with the attitude of the aircraft in the parked position, i.e. doors open, gear down.

Recommendation:

Based on the AAIB recommendations, the FAA is recommending that owners/operators of Consolidated Vultee 28-5ACF, PBY-5, PB Y-5A, Army OA-10, OA-10A, RCAF PBY-5A, RCAF 28-5AMC aircraft (and PBY-6A because of their similarity), accomplish the following as soon as possible:

a) Perform a detailed visual inspection of the ri ght and left-hand nose gear bay door torque tubes, (both tubes have the same Part Number 28B4028) externally and internally.

b) Permanently remove any plugs or bungs installed in the torque tubes. Inspect torque tubes in accordance with paragraph a).

Note: The Illustrated Parts Catalog, AN 01-5M-4 does not show any plug in the torque tube.

Removal of the plug will allow water or condensation to drain or evaporate.

c) Repair or replace any corroded parts in accordance with Advisory Circular AC 43.13-1B.

2 ANM-99-31

d) The AAIB report also recommended publication of specific rigging instructions for the nose gear bay doors. At this tim e FAA does not have access to any such instructions and is hereby asking for owners/operators for their support. Please send your recommendations for these rigging instructions within 60 days of the date of this SAIB to Maurice P. Cook, Senior Engineer, Airframe Branch, Los Angeles Aircraft Certification Office, 3960 Paramount Blvd., Lakewood, CA 90712-4137, telephone: (562) 627-5230; fax: (562) 627-5210; or email:

maurice.cook@faa.gov.

e) Incorporate the inspection requirements of pa ragraph a) and rigging instructions for the nose gear bay doors into the FAA Approved Aircra ft Inspection Program (AAIP). Inspections should be accomplished annually or earlier depending on the environment of aircraft operations.

For Further Information Contact:

Mr. Maurice P. Cook, Senior Engineer, Airframe Branch, Los Angeles Aircraft Certification Office, 3960 Paramount Blvd., Lakewood, CA 90712-4137, telephone: (562) 627-5230; fax:

(562) 627-5210; or email: maurice.cook@faa.gov.