Seattle - After Allied Pilots Association and Southwest Airlines Pilots Association, another U.S. pilot union is complaining about the lack of information on pilot training manuals of Boeing 737 MAX jets.

A safety feature concerning the false angle of attack data is under investigation after Lion Air crash last month.

Zwingly Silalahi, the operations director at Lion Air, also uttered his disappointment during an interview yesterday.

There are no details about the Maneuvering Characteristics Augmentation System in Boeing’s latest manual updates,
said Silalahi.

Now a third pilots’ union, the Air Line Pilots Association, wrote to Federal Aviation Administration on November 15th, expressing the Union's anxiety about the lack of documentation for a critical safety procedure.

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.

Air Line Pilots Association (ALPA) represents the pilots at United Airlines,

Two other pilot unions, the Southwest Airlines Pilots Association and the Allied Pilots Association have quoted similar concerns at the beginning of the week.

Pilot unions claim safety features tied to Lion Air crash are not included in training manuals

A safety measure, which intervenes when a sensor sends false angle of attack data led the aircraft dive sharply before it crashed into the Java Sea on Oct. 29 with 189 people on board.

A sensor which calculates how high the plane’s nose during the flight sent wrong signals to flight computer prompting a dive command, experts believe.

Boeing says pilots could have managed the situation with an existing emergency procedure, but Pilot Unions claim the procedure is not detailed enough on documents.

Boeing sent a service bulletin to 737 MAX operators after FAA ordered the manufacturer to update flight manuals.

Lion Air is waiting for more detailed information about MCAS (Maneuvering Characteristics Augmentation System) probes.

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,
Silalahi said.