MAX Flight Tests May Start Monday


FAA and Boeing test pilots will start wringing out the updated version of the Boeing 737 MAX flight control software on Monday, according to a report by Reuters. Citing unnamed sources, the news agency said the pilots will spend three days in various flight configurations to test the effectiveness of the rewrite of software for the Maneuvering Characteristics Augmentation System (MCAS). The system was a major factor in two fatal crashes of the MAX, one in Indonesia in late 2018 and another in Ethiopia in March of 2019.

The report says Boeing pilots have already logged hundreds of hours testing the new software and Monday will be the first flight with FAA pilots on board. It’s the first critical step toward a signoff flight by FAA Administrator Steve Dickson, a former F-15 and airline pilot. Assuming the administrator is satisfied, the 18-month grounding could be lifted by September with a return to service by the end of the year. That timeline could be optimistic.

“Based on how many problems have been uncovered, I would be stunned if the flight tests are ‘one and done,’” one of Reuters sources is quoted as saying. “(The FAA will) make sure they find enough stuff wrong to demonstrate they are putting this jet through its paces. The last thing the FAA or Boeing wants is for the Administrator to do his own flight and say ‘it’s not ready.’ Boeing wants Dickson’s flight to be a coronation.”

MCAS was supposed to run in the background, automatically adjusting the flight behavior of the MAX to adjust for the aerodynamic influence of the plane’s larger and repositioned engines. In the two crashes, incorrect data from a single angle of attack indicator caused MCAS to make aggressive uncommanded movements of the horizontal stabilizer that eventually resulted in the aircraft entering high-speed dives regardless of the pilots’ desperate efforts to regain control.

With the new software, Boeing has made MCAS require agreement from two AOAs before triggering and made it easier for pilots to disable the system if it does malfunction. Although the aircraft may be declared airworthy, it could be some time before MAXes carry paying passengers. Thousands of airliners around the world are parked because of the effects of the novel coronavirus pandemic and the MAX is not included in the sharply curtailed schedules of the airlines that are still flying.

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  1. After reading about the Max from this article pasted by Tyler H on the Pakistani story ( Thanks Tyler) if gives a real perspective on this aircraft operating in third world countries with lots of money.

    The common sense and standards taken for granted in flying is completely out the window in these Countries. Boeing is between a rock and a hard place trying to design something uncrashable with pilots that are clueless. Ex. The Ethiopian max hit the ground straight in at full power going close to 600mph with the 200hr copilot with 4 months of Cessna 172 time under his belt and the robot pilot unable to cope and actually leaving the throttles fwd. Its like the Bonanza Dr. totally relying on the auto pilot in IMC only this time with 200 people on board in a 737.

    The FAA is under scrutiny for sure on this one ( and Boeing) but unfortunately the problem with the MCAS could have been remedied without death if flown by a properly trained flight crew. At least the FAA is keeping these operators from flying in the USA and away from the domestic paying passenger.

    • Correct. Non-Western nation airlines have for far too long been having training programs revolving around being dependent on the autopilot system and not focusing any of the core stick and rudder mechanical flying skills necessary to get one out of trouble in unusual situations. This was also a leading factor in the completely preventable Asiana 777 crash at SFO. What captain has thousands of hours and can’t simply hand fly an aircraft to the ground? Hell what Cessna pilot can’t do that? None I know of.

    • Worse. Desperately failing to USE the electric trim properly. Any use of the electric trim disables MCAS for several seconds. They could easily have held the electric trim thumb switches until the airplane returned to a neutral trim state and THEN turned off the electric trim system (using the time frame while MCAS remains disabled). But they didn’t. They turned it off while in a horribly out of trim state, and then couldn’t get back.

  2. I didn’t fly the 737, but I did fly the 727, which has a similar trim setup. Boeing, knowing how fast things can happen with a runaway trim, included a mechanical brake on the 72 and early 73’s which would engage anytime electric trim was opposed by the opposite movement of the yoke, stopping the runaway trim and giving the pilots time to engage the trim cutoff switches. This feature was removed on the MAX, exposing it to grossly out of trim situations.
    A question I would like to see answered by Boeing is can the MAX be safely flown without MCAS? If not, why not?
    The answer may be in the MAX’s MEL, if anyone has access, they could answer this.

  3. Hummm – when this was originally certified (Max), numerous flight test were made as req’d.
    Of course the problem did NOT show up then, so, will the new tests really prove anything?  Ha Ha
    (for future flying I mean)
    I’m quite sure, by now, EVERY 73 pilot is quite a where of the stab cut out
    (OH yes, I forgot, need training to learn how to turn off switches)

      • OK then, you’re hand flying the MAX, the stab trim starts running, how do you know if you have a runaway stab, or just normal MCAS operation? I for one, would be very nervous every time that trim wheel started to run on its own. That could be quite a distraction right after takeoff, one hand on the yoke, the other on the stab trim cutout switches.

          • Thanks again YARS. With the new limitations Boeing is talking about, this may no longer be a problem.

        • 4 modes of Stabilizer trim
          1. Auto Pilot Stab Trim: Trims Stab with A/P engaged.
          2. Speed Trim: Trims Stab when flaps not up and high power settings (Take Off)
          3. MCAS: Flaps up Auto Pilot not engaged.
          4. Manual Trim
          All modes of stab trim are functions of Flight Control Computers (except for manual trim).
          If the stab is trimming with A/P disengaged and flaps up with no abnormal pitch up attitude. I’m hitting STAB DISCONNECT SWITCH.
          In the event that I did not know about MCAS If the stab is trimming with A/P disengaged and flaps up again STAB TRIM DISCONNECT.