FAA issues Airworthiness Directive on cracks in pickle forks on Boeing 737NG aircraft

Last Update: October 10, 2019 / 19:14:26 GMT/Zulu time

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Incident Facts

Date of incident
Oct 3, 2019

Classification
News

The FAA have issued Airworthiness Directive AD-2019-20-02 requiring repetitive inspections of the so called "pickle forks", a suspension system for wing-fuselage mounts, for all The Boeing Company Model 737-600, -700, -700C, -800, -900, and -900ER series airplanes.

The FAA reports: "In September 2019, the FAA received reports of cracking discovered in the left and right hand side outboard chords of the station (STA) 663.75 frame fittings and failsafe straps adjacent to the stringer S-18A straps on multiple Boeing Model 737-800 airplanes during a passenger-to-freighter conversion. The affected airplanes had accumulated between 35,578 and 37,329 total flight cycles. Cracking in the STA 663.75 frame fitting outboard chords and failsafe straps adjacent to the stringer S-18A straps, if not addressed, could result in failure of a Principal Structural Element (PSE) to sustain limit load. This condition could adversely affect the structural integrity of the airplane and result in loss of control of the airplane."

The FAA stated: "This AD requires repetitive inspections for cracking of the left and right hand side outboard chords of the STA 663.75 frame fittings and failsafe straps adjacent to the stringer S-18A straps. This AD also requires repair of all cracking using a method approved by the FAA or The Boeing Company Organization Designation Authorization (ODA). This AD also requires sending a report of all results of the initial inspection to Boeing."

The AD is currently considered interim action.

On Oct 10th 2019 Southwest Airlines (USA) reported they found cracks in the pickle forks of two of their aircraft and grounded them, Gol Transporter Aereos (Brazil) reported they found cracks in the pickle forks of 11 of their aircraft.

On Oct 10th 2019 Boeing reported 810 jets have been inspected so far, of them 38 were found with cracks in the pickle forks requiring repair.

Boeing's patent US9399508B2 explains the function of the pickle forks, so called because of their shape.
Incident Facts

Date of incident
Oct 3, 2019

Classification
News

This article is published under license from Avherald.com. © of text by Avherald.com.
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