After you grow the extension and contraction when a product of take-off and landing cycles, you run a menace of getting fatigue, supposed CBS News aviation safety expert indication Rosenker, a ex- chairman of the NTSB. You run the gamble of getting cracks happening the metal itself.FAAs emergency order yearn for require preliminary inspections using electromagnetic campaign on several Boeing 737 aircraft stylish the -300, -400 and -500 succession to facilitate give accumulated further than 30,000 takeoffs and landings, the agency supposed. It yearn for subsequently require repetitive inspections next to regular intervals.The FAA has complete programs during place to keep industrial aircraft from structural smash up in the function of they age, assumed FAA Administrator Randy Babbitt.But amount Voss, president of the getaway Safety Foundation fashionable Alexandria, Va.