FAA Orders Checks on Some 737 Engines

The government ordered immediate inspections on engines running the newest Boeing 737s Thursday after broken engine parts prompted two in-flight engine shutdowns last week.

The “telegraphic airworthiness directive,” second only in urgency to an emergency directive, orders immediate inspections on 46 engines installed on 23 U.S. airliners, 13 of which are owned by Southwest Airlines. Nine others are owned by Continental Airlines and one is owned by Eastwind Airlines.

The directive also states that the engine part in question, the accessory gearbox starter gear shaft, must be replaced on all of the aircraft by Sept. 1 or within the next 750 flight hours, whichever comes first.

The Federal Aviation Administration issued the directive after learning of two incidents last Friday involving the latest versions of the world’s most common airliner, the Boeing 737-700 and -800 aircraft. They are equipped with CFM International CFM56-7B turbofan engines, made by General Electric and the French company Snecma.

The pilots for two jets flown by Russia’s Transaero Airlines and Norway’s Braathens Airlines had to shut off one of their aircraft’s two engines after a gear shaft broke. No one was hurt in either incident.

Subsequent investigation determined that the shafts cracked because of high stresses during manufacturing. The process has since been changed.

Boeing spokesman Russ Young said his company, which does not manufacture the planes’ engines, had no comment on the order.

The directive orders the immediate inspection of the magnetic chip detector aboard the right-hand engines on all 737-700 and -800 aircraft. The detector senses metal chips from engine components, a warning sign of engine failure. If the detector contains abnormal magnetic particles, the starter gear shaft must be replaced immediately.

The same routine must occur the following day with the left-hand engine. The inspection order was selected because the gear shaft is located on the left side of the engines, meaning that the one on the plane’s right side is closer to the passenger compartment. Officials are concerned about spraying engine parts entering the cabin and hurting passengers.

Regardless of the results of the inspection, all of the gear shafts must be replaced by the end of the summer.

Worldwide, there are 94 such engines installed on 47 airplanes. FAA orders apply only to U.S.-registered airliners, but foreign carriers typically follow the agency’s lead on safety matters. The estimated cost of repairs to the U.S. fleet is $536,000.