Unapproved Selector Or Placard Could Lead To Inadvertent Fuel Shutoff

The FAA has issued a Special Airworthiness Information Bulletin (SAIB) concerning the possible installation of an unapproved fuel selector valve and/or placard that may result in shutting off fuel flow to the engine during flight. The SAIB applies to Boeing Models (North American) AT-6, AT-6A, AT-6B, AT-6C, AT-6D, AT-6F, and T-6G airplanes.

The SAIB recommends the verification of the appropriate fuel system placards and associated mechanical provisions designed to prevent inadvertently selecting the fuel selector position that would unknowingly shut off fuel flow.

According to the document, on May 17, 2016, a Model AT-6A airplane departed Falcon Field (Mesa, Arizona), Runway 22L in a formation flight for the purpose of sightseeing. Shortly after departure, witness statements indicated that the airplane appeared to lose power and the engine made popping noises. An emergency landing was performed and resulted in a crash landing onto a road that borders the west side of the airport. The airplane was destroyed by post impact fire and both occupants suffered fatal injuries.

During the post-crash investigation, it was apparent that the fuel system did not fully conform with the design features contained in Supplemental Type Certificate (STC) SA00636CH.

There are three notable findings that are relevant to this SAIB:

• the fuel selector lever pointer was positioned in an unmarked painted white area on the placard, which shut off fuel;
• the fuel selector valve and placard did not have the required obstruction screws and selector lever to prevent moving the selector to the unmarked area; and
• the fuel selector placard was marked incorrectly.

The FAA determined that the AT-6 fuel selector problem is likely an isolated event. The fuel selector was not approved for installation, and there is not a known similar fleet population of aircraft with this unapproved part installed.

The agency recommends that owners and operators verify that the correct fuel selector placards and obstruction design features are installed.

(Image from file)

FMI: SAIB (with recommended placards)