US aviation regulator issues warning over Boeing 737 rudder issue

Company has delivered 291 commercial aircraft this year as of September 30, including 229 737 Max jets

Boeing 737 Max aircraft are assembled at the Boeing Renton Factory in Washington state. AFP

The US aviation regulator issued a safety alert to airlines on Tuesday, warning of potential risks related to restricted or jammed rudder movement on certain Boeing 737 aircraft.

The Federal Aviation Administration said the warning includes details about an automated system check of the rudder system, which “would identify limited or jammed rudder movement during approach [phase] prior to landing”, Reuters reported.

The rudder on an aircraft's tail controls the side-to-side movement of the plane's nose, also known as yaw motion.

The alert followed a statement last week by the National Transportation Safety Board, which said that more than 40 foreign operators of Boeing 737 Max or Next Generation planes may be using rudder components that could cause safety issues.

Last month, the board issued a warning that a defective part in some Boeing 737 aircraft could cause the plane’s rudder control system to jam. Nearly 350 components, supplied by Collins Aerospace, a unit of RTX, for 737 Max and 737 NG aircraft, have been affected, the NTSB said. It issued precautionary measures to both the FAA and the aircraft manufacturer.

Boeing is dealing with a series of crises related to the safety of its aircraft and its manufacturing process.

The Virginia-based company on Tuesday said it had delivered 291 commercial aircraft this year, as of September 30, including 229 units of the 737 Max jet. The company, which is expected to announce its last quarter earnings on October 23, was trading 0.68 per cent down at $154.85 a share at 2.20pm New York time.

The NTSB is investigating a February 6 incident in which the rudder pedals on a United Airlines Boeing 737-8, a Max variant, were stuck in their neutral position during landing at Newark Liberty International Airport in New Jersey. There was no damage to the plane or injuries to the 155 passengers and six crew members.

Investigators found evidence of moisture in both actuators – a device that controls components such as flight control surfaces and landing gear, which failed testing. Collins Aerospace subsequently determined that a sealed bearing was incorrectly assembled during production of the actuators, leaving the unsealed side more susceptible to moisture that can freeze – as a result limiting rudder system movement.

Last week, NTSB chairwoman Jennifer Homendy said in a memo to the FAA that the board was worried about the “possibility that other airlines are unaware of the presence of these actuators on their 737 airplanes”.

Boeing did not immediately respond to The National’s request for comment.

Earlier the plane maker said it was working with its supplier to “develop additional guidance to address” the problem with the rudder system. It alerted operators of a potential faulty condition in rudder system in August.

“We will also ensure flight crews have the appropriate operating procedures,” the company said.