The basic checklist for dealing with a problem known as stable stabilizer trim has been substantially unchanged since 1967, the earliest days to 737 jetliner, according to Dennis Tajer of the Allied Pilots Association. He said FAA officials told the airline's security officers and pilots associations in April of the review.
Such a review is "unusual" after an accident, said David Soucie, a former FAA security inspector who is now CNN security analyst. Changing the checklist may require pilots to undergo additional training.
The trim on the horizontal stabilizer, on a fly's tail, is a way to control how steep the plane climbs or descends. In addition to manual control, it can be moved by the autopilot and a new feature in 737 Max that has come under the control of crash scientists, Maneuvering Characteristics Augmentation System, known MCAS. The checklist is intended to give pilots an emergency method to override automated systems and gain control of the aircraft.
Ask to comment on the review, a FAA spokesman CNN told the agency's statement on the April 1
Tajer said the Allied Pilots Association, representing 15,000 pilots of American Airlines, was prepared for that meeting to ask the FAA for a quicker checklist check. He is concerned that the FAA, in his view, has not taken a sufficiently practical approach to regulate Boeing and revise its work and conclusions.
"I want them to be invasive. I want them to be aggressive. I want them to be keen to know all the information," he said. "I want them to be more than trust, but confirm."
The FAA has repeatedly defended its certification by Max, as involved – by legislation delegated to Boeing's employees.
"FAA's flight certification processes are well established and have consistently produced safe aircraft designs," the agency said in a statement. "The 737-Max certification program took five years and involved 110,000 hours of work from FAA personnel, according to FAA's standard certification process."
Tajer said that although the basic steps are not changing, Spartan checklist can be spread with instructions such as those found in the Boeing add-on: "It can take two pilots to manually trim the plane." "It may require lift load to manually trim the plane."
In the wake of the October Lion Air crash I Indonesia issued Boeing a bulletin for pilots that reinforced the procedure and revealed the MCAS system. Since the second 737 Max crash, in March in Ethiopia, Boeing has disappeared the stabilization trim procedure as sufficient. The two crashes killed 346 people.
"Our analysis found that a pilot could counter the wrong system input by using the triggers on the control wheel, or by following the stabilization procedure and using manual trim," a Boeing spokesman said in an April statement. The statement added that "the current flight crew response to indefinite trim, for whatever reason, is contained in existing procedures."
The Indonesian and Ethiopian preliminary reports both say that the pilot followed the procedure. Both aircraft eventually collapsed. The reports do not look like an improved checklist could have turned out to be life-saving, but the Indonesian report notes: "None of the checks performed contained the instruction" Plan to land at the nearest appropriate airport. ""
"The crew performed the grid stabilizer checklist and set the switch to the trim cutout to cutout position and confirmed that manual trim operation did not work," the preliminary Ethiopian crash report shows.
Pilots and experts often refer to the checklist of the stabilizer trim as a "memory element", an emergency procedure that pilots train repetitively and can perform almost instinctively.
"The elements involved in your brain come across hours and hours of simulator training," explains security analyst Soucie, and changes in them may require pilots to perform additional simulator training.
Tajer said FAA officials also revealed reviews of two other emergency lists – to deal with inaccuracies called airspeed and attack angle – and that assessments can help determine if lists contain details they need for generations of 737 later.
The procedures are not up to date, he said, "since Lyndon Johnson was president and the country is struggling with the Vietnam War."