The FAA has issued the following SAIB to owner/operators of Grumman/Gulfstream American G-73 Amphibs, just days after the fatal accident that took down a Chalk's G-73 involved in commercial passenger service.

Background

This Special Airworthiness Information Bulletin (SAIB) informs you, a registered owner or operator of a Gulfstream American G-73 airplane, of the current findings related to an accident involving a G-73. This SAIB also applies to airplanes that may also be identified as a model G-73T. On December 19, 2005, a G-73, modified by STC SA2323WE to install Pratt and Whitney PT6A engines and STC SA4410SW to increase the passenger count to 17, experienced a wing separation on take-off off the coast of Florida. The wing separated between the fuselage attachment and the engine attachment.

Preliminary indications from the investigation by the NTSB and FAA reveal occurrences of fatigue failure of a wing spar. This particular airplane was operated in passenger service and in a salt-water environment.

Information

At this time, the initiating cause of the failure is unknown. The FAA is closely monitoring the investigation to determine the existence of a condition on the accident airplane that may be manifest on other G-73 airplanes in the existing fleet. At this time, the FAA is not able to identify an inspection or other action that can be taken to determine whether other aircraft may have the same condition. FAA is considering the need for mandatory detailed inspections of parts or all of the wing structure on the fleet of G-73 airplanes. If FAA determines that the accident airplane wing’s pre-separation condition is potentially manifest in other G-73 airplanes, the FAA will take appropriate action.

For Further Information Contact
Rob Romero, Aerospace Engineer, FAA, Fort
Worth Airplane Certification Office, 2601
Meacham Boulevard, Fort Worth, Texas
76193-0150; telephone: (817) 222-5102;
facsimile: (817) 222-5960;
e-mail: Robert.A.Romero@faa.gov.

FMI: www.faa.gov/aircraft/safety/alerts/