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Unions raise alarms over 737 MAX emergency warning systems

written by Hannah Dowling | September 23, 2020

737 MAX Family in flight (Boeing)

A number of aviation workers unions have now raised concerns over the 737 MAX’s emergency alerting systems within the cockpit, and called for an overhaul on both systems and procedures.

The union representing safety engineers at the Federal Aviation Administration (FAA) has joined over 200 other responders in posting a public comment on the proposed safety and procedural changes introduced by Boeing and the FAA during its public consultation period.

In its submission, the FAA engineers union called for substantial upgrades to the flight crew alerting systems and procedural changes prior to the aircraft returning to service.

The FAA’s own technical safety experts have highlighted that Boeing has not yet done enough by just fixing the flight control system – MCAS – that caused the two fatal crashes, and that the planemaker must also address the chaos and confusion caused by emergency alert systems within the cockpit during both tragedies.

Many have highlighted the fact that, in both fatal crashes, multiple warning systems set off by a single erroneous AOA sensor caused serious distraction and confusion for the pilots, as they attempted to manually take back control of the plane.

During the initial certification of the aircraft, Boeing successfully managed to get out of meeting the latest FAA requirements governing how cockpit warning systems inform pilots that something has gone wrong.

The 737 MAX was then granted exceptions to five of the regulatory stipulations by the FAA, so that it could retain the legacy 737 instrument panel and crew alert system, something that was crucial for Boeing in its marketing of the MAX.


The FAA engineers union has now said that those exceptions should be rescinded, and the crew alerting system within the recertified MAX must be updated accordingly.

This proposal is highly unlikely to be taken onboard by Boeing, as it would require extensive revisions to the instrument displays within the cockpit, as well as renewed pilot training on these new systems.

Boeing has said it hopes its embattled 737 MAX would re-enter commercial service by the end of the year.


Meanwhile, the US pilot unions have taken similar issue with some of the aircraft’s emergency warning systems.

The Air Line Pilots Association and Allied Pilots Association both submitted their thoughts on the update’s safety and procedural changes proposed on the 737 MAX to the FAA during its public consultation period.

Both unions took issue with the current warning systems, and hoped the regulator and Boeing would introduce an appropriate procedure to override these loud and persistent warnings, that could work to distract pilots amid emergency scenarios.

One such warning that pilots deemed potentially harmful during emergency situations on the 737 MAX is what the unions called a “stick shaker”, in which the pilot’s command control column begins to loudly and rapidly vibrate.

Pilots raised concerns about this warning system, particularly in instances when it has occurred mistakenly.

In its comment, the ALPA suggested that a new procedure be introduced that would allow flight crews to identify and manually stop the stick shaker via a circuit breaker, if the alert is confirmed as erroneous. 

This recommendation was shared by Transport Canada following its own flight tests on the aircraft.

In a separate public comment, the Allied Pilots Association also requested a checklist be produced and provided to air crew, in order to disable erroneous stick shaker activation, in addition to an overspeed warning.

The APA also said the FAA should condense a checklist for dealing with a loss of control called runaway stabiliser to help pilots “more rapidly isolate the problem”.

Similar concerns over excessive and distracting cockpit warning lights and sounds were also shared both by Boeing engineer and whistleblower Curtis Ewbank, as well as a combined letter written to the FAA on behalf of the families of the victims who died in the fatal 737 MAX crashes.

The public consultation period for the 737 MAX safety changes officially ended on Monday.

The FAA will now read through recommendations, before making final judgement on lifting the worldwide grounding of the jets.

Unions raise alarms over 737 MAX emergency warning systems Comment

  • AlanH


    The 737 is well past its use-by date. The new LEAP engines are far too big for the airframe. Boeing should have progressed the 757 as its medium-long range single aisle aircraft. It’s a much more capable aircraft, with a more substantial undercarriage that would have accommodated the larger engines better . The 737 was never designed for this role back in the 60s.

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