Lycoming has begun producing replacement crankshafts for turbo-charged piston engines affected by an airworthiness directive (AD) that has grounded hundreds of aircraft. "Crankshafts will be available by early January," says Lycoming president John Wolf.

Because crankshafts will be produced faster than the company can tear down and rebuild engines, Lycoming plans to work with domestic and international service centres to return aircraft to service as quickly as possible. "We will use outside shops to increase capacity, although Lycoming will do more than half the engines," says Wolf. "We should get them done by early in the second quarter."

Around 950 TIO-540-series engines have been grounded by the AD, and almost 740 more must be tested within 50h to see if they exhibit the weakened "honeycomb" grain structure blamed for a series of crankshaft failures. Wolf says the embrittlement resulted from overheating during treatment after forging, and has been tackled by improving control of the manufacturing process at the crankshaft supplier. In addition, each crankshaft will be checked for the honeycomb feature. "An extra piece on the forging will be cut off and sent for testing," he says.

Parent company Textron has taken a $37 million charge to cover producing replacement crankshafts, shipping, tearing down and rebuilding the engines, and paying for alternative transport for owners of grounded aircraft. "Safety was most important, and we had to maintain credibility with our customers, so Textron made a tough financial decision," says Wolf.

Textron has also provided resources to help tackle the crankshaft problem. "They have brought in best practices we have never used before, in metallurgy, engineering and programme management," says Wolf. "We will come out of this a stronger company."

Source: Flight International