U.S. requiring inspections for wire failure on Boeing 737 Classic planes

[May 15, 2021]  By David Shepardson

WASHINGTON (Reuters) -The Federal Aviation Administration (FAA) said on Friday it was requiring U.S. operators of 143 Boeing Co 737 Classic series airplanes to check for possible wire failures stemming from an investigation into an Indonesia crash in January.

The FAA is issuing an airworthiness directive requiring operators to verify the flap synchro wire, which plays a role in the operation of the aircraft’s auto-throttle system, is securely connected to a safety sensor. The wire failure could go undetected by the auto-throttle computer on the affected airplanes and pose a safety risk.

The FAA said the issue impacts 1,041 737-300, -400 and -500 Classic series airplanes worldwide. The 737 Classic is an older generation of planes more than two decades old. The newer 737 MAX and 737 NG are unaffected by the directive.

The FAA is requiring some speedier checks than what Boeing had suggested to operators.

Boeing did not immediately comment.

The FAA and Boeing identified the potential problem as part of the ongoing investigation into the Jan. 9 crash of Sriwijaya Air Flight 182 in Jakarta, Indonesia.

The 26-year-old Boeing Co 737-500 crashed into the Java Sea shortly after takeoff from Jakarta, killing all 62 people on board.

The FAA said there is no evidence the flap synchro wire issue played a role in the accident but said the possibility of a failed connection presents a safety concern that warrants prompt attention.

The Boeing logo is pictured at the Latin American Business Aviation Conference & Exhibition fair (LABACE) at Congonhas Airport in Sao Paulo, Brazil August 14, 2018. REUTERS/Paulo Whitaker

Indonesian safety investigators said in January they were investigating whether a problem with the auto-throttle system contributed to the crash given an issue with it had been reported on a flight a few days earlier.

Boeing issued a March 30 message to operators directing them to perform electronic checks of the auto-throttle computer to confirm the wire is connected within 250 flight hours.

The FAA is requiring the initial test within 250 flight hours or two months from now, whichever occurs first, "to ensure that airplanes with low utilization rates are addressed in a timely manner." Operators must then make repairs if needed.

The FAA said a faulty connection could result in the failure of the auto-throttle system to detect the position of the aircraft’s flaps if the plane’s engines are operating at different thrust settings due to another malfunction.

The FAA is requiring follow-on inspections every 2,000 flight hours after the initial inspection.

Impacted U.S. operators are Aloha Air Cargo, DHL, iAero Airways, Kalitta Charters and Northern Air Cargo, the FAA said.

(Reporting by David Shepardson in WashingtonEditing by Matthew Lewis)

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