Guy Norris/SEATTLE
The US Air Force is pushing to accelerate a series of planned engine upgrades to the Pratt & Whitney F100-220 and -220E-powered Lockheed Martin F-16 fleet, following several engine related crashes, the latest in March near Luke AFB, Arizona.
The Israeli air force temporarily grounded its F-16s after the crash of an F-16D on 28 March. An Israeli air force source says there is full co-operation with the USAF in the investigation of the US F-16 accidents.
Five Luke-based F-16s have crashed in the past six months and the latest incident prompted the USAF to ground about 400 aircraft while inspections were carried out. At least two of the events are thought to be due to a weld failure in the augmentor duct. "Ongoing inspections have found cracks in augmentor ducts," says Pratt & Whitney, which has sent teams to help train USAF personnel to perform close inspections.
By 16 April, cracks had been found in the tack welds in supports alongside the ducts of 17 -220/220E engines. The problem does not affect the augmentor duct of the more powerful -229 engine which is chemically milled, rather than welded. As a long term solution, the USAF has a planned upgrade programme to replace the -220/220E units with the -229 duct, but the effort has been delayed by funding shortages.
The weld problem is known to have caused an accident at Luke in February when the engine nozzle and entire augmentor assembly detached on long finals.
The incidents may help spur other upgrades, including replacement of the -220's third stage fan blades and disc, and speeding up the retrofit of an improved low pressure turbine module.
Source: Flight International
