The Federal Aviation Administration has proposed a rule to require all US-registered Boeing 737NGs be inspected for worn components that can cause excessive horizontal stabiliser movement.
“The FAA has received reports from multiple operators of pitch oscillations events due to excessive horizontal stabiliser free play,” says the proposed rule, released on 8 January. “Currently, there is no inspection requirement in place to address the wear of the left and right horizontal stabiliser pivot hinges and jackscrew.”
The excessive stabiliser movement “could lead to a flutter event”, the proposal adds.
The FAA intends to require operators address the issue by following steps already specified by Boeing.
“The proposed airworthiness directive would make mandatory the same guidance Boeing issued to operators in June 2025,” the company says.
In that guidance, Boeing instructs operators to measure “free play of the left and right horizontal stabiliser pivot hinges and the jackscrew to determine free play value”, and to replace worn parts, says the FAA.
The proposed order would affect 1,987 US-registered 737NGs – the entire fleet, including -600s, -700s, -800s, -900s and -900ERs.
It is unclear how many of those aircraft have already been inspected by operators per Boeing’s June 2025 guidance.
The FAA is accepting comments about its proposal for 45 days.
