Paul Lewis/WASHINGTON DC
US Air Force (USAF) and NATO Flying Training in Canada (NFTC) operated Raytheon T-6 trainers will remain grounded pending the outcome of two separate investigations into the crash of a trainer and an earlier incident involving an engine seizure.
NFTC's fleet of 16 T-6s, designated Harvard IIs, have been grounded for the last three weeks following an in-flight engine failure. Two instructors managed to dead-stick the trainer back to the nearby Moose Jaw airbase.
The failure has been attributed to a seizure of the aircraft's Pratt & Whitney Canada PT6A-68 turboprop engine as the result of an oil loss from a failed oil cooler, made by Lorri. Full results of the investigation are expected to be released by mid-September.
The 12 Texan II trainers delivered to the USAF have also been grounded after the 31 August crash of an aircraft from the 12th Flying Training Wing during instructor familiarisation. It was on approach to a local airport near San Antonio, Texas, when it crashed. Both instructors ejected safely.
An investigation board has been convened to look into the accident. In the meantime the remaining nine T-6s with the training wing and two more assigned to the operational test and evaluation unit also at Randolph AFB remain on the ground.
Raytheon has not stopped production, but has suspended deliveries to the USAF, which has ordered 372 aircraft to replace its Cessna T-37s. The US Navy is due to receive the first of 339 T-6s in 2002. Another eight remain to be delivered to the NFTC, while the Greek air force recently took the first of 36.
• The first of 84 UK Royal Air Force Shorts Tucano T1 basic trainers grounded on 4 September are expected to be airborne again this week following a fleet-wide check after discovery of a rudder mechanism fault.
Failure of the rudder pedal bearing casing in one of the single-turboprop aircraft on 1 September triggered checks in which bearing casing cracks were discovered in several other aircraft.
The UK Ministry of Defence also says that it has not been determined yet whether the basic fault is metal fatigue or another cause.
• The latest grounding of the Bell Boeing V-22 Osprey has been lifted after inspection of interconnect driveshaft couplings on the 11 tiltrotors so far delivered. A US Marine Corps MV-22 was recently forced to make a diversionary landing after a warning that one of the couplings had loosened and disengaged the gears.
Source: Flight International