Third Pilots' Union Raises Concern About Boeing 737 Max Jet

(Bloomberg) -- A third U.S. pilots’ union is raising concerns about what it says is a lack of information provided by Boeing Co. on a safety system installed on the new 737 Max aircraft that is under a spotlight after last month’s crash off the coast of Indonesia.

The operations director at Lion Air, the carrier that crashed last month, also expressed frustration in an interview Thursday with what he called a lack of information on that safety feature. “There are no details” about the Maneuvering Characteristics Augmentation System in Boeing’s latest manual updates, said Zwingly Silalahi.

The Air Line Pilots Association, which represents United Continental Holdings Inc.’s flight crews, wrote to Federal Aviation Administration Acting Administrator Dan Elwell Thursday saying it was “concerned that a potential, significant aviation system safety deficiency exists” and asking for more details.

“There appears to be a significant information gap, and we want to ensure that pilots operating these aircraft have all of the information they need to do so safely,” wrote Captain Tim Canoll, ALPA’s president.

Two other pilot unions -- the Southwest Airlines Pilots Association and the Allied Pilots Association at American Airlines Group Inc. -- raised similar concerns on Monday.

A safety system on the Max apparently pushed down the nose of a Lion Air flight near Jakarta shortly before it dove into the Java Sea on Oct. 29 with 189 people aboard, according to investigators in that country. Boeing says pilots could have dealt with the issue using an existing emergency procedure, but issued bulletins to carriers that was followed by an order to update flight manuals by the U.S. FAA.

Boeing said in a statement that it has provided two updates to airlines on the new safety feature and was confident in the safety of the 737 Max family of jets. The company said it is “taking every measure to fully understand all aspects of this incident, working closely with the investigating team and all regulatory authorities involved.”

Boeing extends “our heartfelt condolences and sympathies” to victims’ families, it said.

“The bottom line here is the 737 Max is safe,” Chief Executive Officer Dennis Muilenburg said earlier this week on Fox Business Network. “This airplane went through thousands of hours of tests and evaluations, certification, working with the pilots, and we’ve been very transparent on providing information and being fully cooperative on the investigative activity.”

Pilots on the Lion Air flight were receiving erroneous speed readings, a problem that had occurred on three previous flights, according to the Indonesia National Transportation Safety Committee. They had radioed air-traffic controllers to say they intended to return to land.

A sensor that measured how high the plane’s nose pointed relative to the wind also sent false signals to a safety system, prompting a computer on the plane to command a dive, according to the investigative agency.

After Boeing and the FAA highlighted how the Maneuvering Characteristics Augmentation System works and pointed to an existing emergency procedure to counter any malfunctions by it, pilots in the U.S. said they should have been given more information.

Lion Air’s Silalahi said he is still waiting for more details about MCAS works. “As of now, we can only guide our pilots on things that are not related to MCAS, because Boeing manual has not told us how to deal with this,” he said.

©2018 Bloomberg L.P.