LE BOURGET, France
737 MAX jetliners in the air were delayed in part by concerns as to whether the average pilot has sufficient physical strength to move one mechanical crank to turn in extreme cases emergencies.
The concern has made the crank – which moves a horizontal plate at the stern of the aircraft – to the focal point of engineering analyzes, simulator sessions and flight tests by the aircraft manufacturer and US air safety officers. The extent of the internal debate has not been reported so far.
The use of the crank is the last step in an emergency checklist to counteract tail lift tail dangerous movements, such as in MAX's two deadly crashes, when an automatic flight control system fails.
By turning the crank to adjust the horizontal stabilizer, the angle of the aircraft nose can be changed. Under certain conditions, even at unusually high speeds, when the panel is already at a steep angle, moving the crank can take a lot of power. Among other things, those familiar with the details are concerned about whether female pilots ̵
The analysis could be even more significant as the same emergency procedure applies to the generation of the jetliner that preceded the MAX, known as 737 NG. Around 6,300 of these aircraft are used by more than 150 airlines worldwide and are the backbone of short- and medium-haul fleets for many airlines.
Neither Boeing nor the regulators believe that the review will result in changes to the design or features. However, the problem has forced a reassessment of some security assumptions for all 737 models, as previously reported by the Wall Street Journal.
The global MAX fleet of about 400 aircraft was discontinued in March after two fatal crashes that were triggered by the US Air Force, misfiring an automated flight control system called MCAS. In the two accidents, a total of 346 people were killed.
Boeing's 737 MAX was developed to meet the growing international demand for air travel, and became its best-selling aircraft. Jason Bellini of WSJ is examining how the creation of the fleet after the crash of Ethiopian Airlines could have a significant impact on the future of Boeing. Photo: Getty
There are no plans to prevent certain pilots from escaping control of a 737 model because of their strength, if they know about the considerations. However, those in charge of Boeing and the Federal Aviation Administration fear that the public's discussions may be exaggerated or sensitized, according to industry and government officials familiar with the process.
All underlying security issues for the 737 MAX must be met According to US and European aviation officials, it was decided before the FAA could return the groundwater to the air.
Asked questions, a Boeing spokesman said, "We will provide the FAA and global regulators with all the information they need. Previously, Boeing reported providing additional information on how pilots interact with the aircraft controls and displays in various flight scenarios.
Prior to the Paris Air Show this week, Boeing CEO Dennis Muilenburg said he wanted to conduct a "thorough, comprehensive review of our design and certification processes" as well as other matters.
An FAA spokesman declined to comment on details. Acting FAA chief Daniel Elwell said the agency is pursuing a full investigation into the two MAX crashes, including emergency procedures, training and maintenance.
FAA Experts Also Want To Examine How Pilot Force Issues Were Treated During Approval Approvals
In simulator sessions and flight tests, the force required to turn the crank under different flight conditions was measured for pilots of both sexes, two respondents said at details.
Hard to turn.
Under certain conditions, pilots are instructed to start a wheel in the 737 MAX cockpit to move the panels on the rear wings of the aircraft.
Adjusting the tail with the crank The horizontal stabilizers of the wings can help change the angle of the nose of the aircraft.
Journal McCartney and the Pilot were involved in a flight simulator test earlier this month Roddy Guthrie, Fleet Captain of the 737 at American Airlines, had trouble turning the wheel. As described in a June 5 article, Captain Guthrie could not move the steering wheel until Mr. McCartney tilted the nose of the aircraft down to relieve pressure on the steering wheel. Take a look at this WSJ image to see how the bike works in both crashes.
Government and industry experts are considering possible changes in operations, training, and pilot handbooks to address security concerns regarding the process, according to the individuals familiar with the details. The results are expected to be part of a package of revised software and training mandates that the FAA will release later this summer.
Capt. Chesley "Sully" Sullenberger, the retired US Airways pilot, celebrated his "Miracle on the Hudson" landing in 2009 and said Wednesday that pilots should spend time in simulators before MAX returns to service, and not only the updates of the MCAS software, but to practice situations in which manually turning the crank would be more difficult. At higher speeds, turning the wheel could require two hands, and the efforts of both pilots might even be impossible.
"You need to develop a muscle memory of their experiences so that they will be immediately available in the future, even in the next few years, when they experience such a crisis," he said Wednesday at a hearing of the House Committee on Aviation Subcommittee on Transportation and Infrastructure.
Mr. Sullenberger told the committee that he had recently witnessed a rebuild of the deadly MAX flights in a flight simulator. He was aware of how the crews could have been overwhelmed without enough time to correct the problem of warnings and warnings.
The former commercial pilot also expressed greater concern about how MAX was designed and certified by regulators. "It's clear that the original version of MCAS had a fatal flaw and should never have been approved," Sullenberger said in a written statement.
"The 737 MAX has been certified to meet the same FAA requirements and processes that have been used to certify previous new aircraft and derivatives," a Boeing spokesperson said in a statement. He also said the company continues to work on the training requirements for global regulators and airlines.
The pending software upgrade is intended to make it easier for pilots to override MCAS, which moves the horizontal stabilizer to direct the nose down.
The FAA tests were conducted after the agency called on Boeing to prepare a new safety assessment for MCAS and its associated emergency procedures, according to US and European aviation officials.
The FAA does not only document the differences in the average strength between men and women in critical security roles. For example, the Pentagon categorizes such information to assess the suitability of some uniformed personnel for specific tasks.
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contributed to this article.
Corrections and Extensions
Capt. Chesley Sullenberger said at a House Subcommittee hearing on Wednesday. In an earlier version of this article, his first name was misspelled.
Write to Andy Pasztor at firstname.lastname@example.org and Andrew Tangel at Andrew.Tangel@wsj.com