FAA grounds Mentor fleet after latest wing failure

 - January 26, 2007, 11:11 AM

A Raytheon Beech T-34 Mentor crashed on December 7 when the left wing snapped off about four inches inboard of the root attach point. The Mentor was being operated by Texas Air Aces/Aviation Safety Training (AST) and crashed near Houston Hooks Field, killing the flight instructor and front-seat passenger. AST’s mission was emergency upset training for major flight departments around the U.S.

This was the second in-flight breakup of an AST aircraft within the past 13 months and the third such accident for the Mentor in five years. On December 10 the FAA issued an emergency AD grounding the entire 475-aircraft fleet of T-34s.

In November 2003, the first AST crash took the lives of company president Don Wylie and a student passenger. A letter expressing the need to continue AST’s mission of professional upset training appeared on the company Web site shortly after the 2003 crash. AST’s chief pilot, Rick Gillenwaters, signed the letter. Gillenwaters was the PIC killed in the December 7 crash.

All three aircraft that broke up in flight were being operated either for emergency upset or mock combat experiences. The first T-34 that broke up (in Georgia in 1999) was operated by Sky Warriors, a mock-combat company that shut its doors shortly after that crash. Like Sky Warriors, AST has also now ceased operations.

After the Georgia crash, the FAA issued an Airworthiness Directive requiring specific aircraft inspections and possible replacement of the Mentor’s wing spar. An aviation maintenance technician familiar with the T-34 estimated about half of the fleet has been modified. Without the modification, the T-34 is limited to non-aerobatic flight with a VNE of 152 knots and no more than 2.5 positive Gs. Aircraft limits in turns are even lower, hence the aerobatic restriction.

The NTSB’s lead investigator, Aaron Sauer, said his initial review showed the December 7 aircraft was in compliance with all current directives at the time of the crash and that the wing failed at the carry-through point, a previously unknown area of weakness. The new spar installed on the T-34 before the crash appeared to be intact. AST asserted that the 2003 breakup aircraft was also in compliance with all FAA requirements.

Members of the T-34 community are outraged at the grounding of the fleet, claiming all three aircraft crashed because they were regularly operated beyond their design limits. “Connect the dots,” one pilot said. “It’s the operators, not the airplanes, that are the problem. Do you think it’s just a coincidence that the only wings lost came off aircraft flying mock-combat maneuvers?”

An FAA spokesman told AIN that the AST aircraft were being operated under Part 91. No specific FAA guidelines currently exist for upset or mock-combat training companies. Some videotape from the T-34’s onboard cameras survived the recent crash and has been sent to the NTSB in Washington, D.C., for analysis.