Physical Pilot Strength Delaying Boeing 737 MAX Re-entry To Service

Pilot strength could be delaying the Boeing 737 MAX’s re-entry to service. Reports have suggested that some pilots may not have the strength to operate the trim wheel in emergencies.

Boeing 737 MAX Trim Pilot Strength
The FAA is exploring the possibility that pilots may not be strong enough to operate the trim tab on the Boeing 737 MAX. Photo: Boeing

The Boeing 737 MAX has now been grounded for over three months while Boeing engineers attempt to fix a deadly flaw in the software. The FAA believes that the 737 MAX will fly again in 2019. However, its currently anybody’s guess as to when exactly this will be. Despite this, many airlines are planning for the aircraft to be out of action until at least September, if not later.

What’s this about pilot strength?

According to the Wall Street Journal yesterday, reporting from the Paris Air Show, the certification process of the aircraft is being delayed. According to their report, there are concerns over whether pilots would be able to operate the trim wheel during an emergency.

The trim wheel is the manual way for Boeing 737 pilots to set the trim on the aircraft. The trim is a portion of the rear elevator which can be adjusted to slightly alter the aircraft’s characteristics for a specific situation.

Boeing 737 MAX Trim Wheel Pilot Strength
Highlighted in Red, the trim wheel as seen in a Boeing 737-800 cockpit. Photo: Cory W. Watts via Flickr

The underlying problem with the 737 MAX that led to its grounding was that software was controlling this wheel. In fact, in certain circumstances, this proved fatal as full down trim was applied. Now, regulators are reportedly concerned that in extreme flight profiles pilots, especially female pilots, will struggle to overcome the forces exerted on the surface.

Is this delaying the 737 MAX’s certification?

Well, yesterday the Wall Street Journal said that this concern was delaying recertification of the Boeing 737 MAX. However, CNBC claims that the Federal Aviation Administration is not concerned about the issue delaying the aircraft.

Despite this, they also claim that the FAA is aware of the pilot strength issue, and is examining it. However, again, this particular issue is not delaying the MAX’s recertification. The Wall Street Journal adds that sources close to the situation have said:

“Neither Boeing nor regulators anticipate design or equipment changes as a result from the review”.

Six months to go

Yesterday, Simple Flying reported that the FAA believes that the Boeing 737 MAX will be back in the skies by the end of the year. As we’re already halfway through the year, this gives a time frame of around six months for recertification.

Boeing 737 MAX Trim Wheel Pilot Strength
The FAA does not believe that the concerns will delay the aircraft’s certification. Photo: Boeing

However, interested parties have time and time again refused to comment on when exactly the aircraft will fly again. The best guess that we have is based on the latest date airlines have postponed 737 MAX flights until.

Do you think pilots would struggle to operate the aircraft’s trim in emergencies? Let us know in the comments!

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Nigel

In the CNBC article cited here, the FAA is quoted as saying that it’s not concerned about this trim wheel issue, because the same trim wheel mechanism has been used for years in the 737 NG. However, this (unfathomable) remark seems to ignore the fact that the 737 NG didn’t have MCAS…and it therefore didn’t have a system that was aggressively pushing the plane into a nosedive. Using the trim wheel in level flight is not an issue, but using it when the horizontal stabilizer is at a highly pitched-down angle can require titanic physical strength. On the basis of… Read more »

Atlas

Ok, if i will fly max i will check how strong the pilot is:)

lowflying

I fly the NG. I used to fly the old 707. Same trim wheel. Same piloting skills required to not get way out of trim, hasn’t changed for 60 years. Every system has a limitation. Disrespect it at your peril.

Every jetliner has a Trimmable Horizontal Stabiliser out of necessity and is susceptible. Read up on AF447, A330 way out of trim but nose up instead of nose down.

I say all this for perspective, not to excuse Boeing and the MCAS.

Nigel

Here’s an analogy: Every car has a handbrake. It’s only used relatively seldom (for parking). For that reason, it’s a relatively crude, mechanical device. Now, let’s suppose your new car has a vicious software feature that — suddenly, and without warning — pushes the accelerator pedal to the floor, and disables the foot brake. How do you stop? You can’t just switch off the engine and roll to a stop, because that will cut off your power steering . So you have to use that relatively primitive handbrake instead. Meanwhile, the car has reached 240 km/h, and you’re trying to… Read more »

Joanna Bailey

Great analogy Nigel 🙂

Never Fly 737 Max

Love your work Nigel – it’s a total system not a silo process… the whole is more than the sum of the parts! All the testing is happening on the ground in simulators at the moment. To me that’s super scary to think a plane with as many known issues as the Max can be re-certified and start flying again based on one final certification flight the proves Boeing has “fixed” the issues! The interesting thing I heard Boeing say the $9 per hour engineers didn’t work on MCAS. I think Boeing would have thought the public will think that’s… Read more »

barry holtzman

We need to seriously consider if we will EVER fly in a Boeing product again!!

Peter Ehrler

I think Boeing themselves have ruined their own reputation in terms of civil aircraft. Simple solution: scrap the short range 737, sell manufcturing rights of the long range aircraft to Embraer, together with Embraer’s short range models they can take over where Boeing has failed. With this, the name Boeing will no longer appear and problem solved.

Joanna Bailey

Interesting idea but I doubt Boeing would want to gift wrap their best selling plane to Embraer, regardless of their relationship or that aircraft’s reputation.

Berndt Andersson

I have read that Boeing has decreased the size of the trimwheel.

Norman Reed

Why the old wheels were a lot bigger and easy to get to now it looks to be about like a trim wheel on a c 172 skyline and harder to get to. Trying to crank that wheel down by your knees with a big load will NEVER work.They need to buy up all of those planes pull the engines and scrap them .you can pt lipstick on a pig but it’s still a pig. It’s the same basic plane that D.B. COOPER bailed out of 50 years ago . How many newer planes have come and done there time… Read more »

Herb33

D.B.Cooper bailed out of the rear stairs on a 727, not a 737.