The United States Federal Aviation Administration (FAA) has says there is currently no basis to call for a grounding of the Boeing 737 MAX fleet.
While a host of regulators around the world, including Australia, China, the European Union, New Zealand and Singapore, have announced temporary suspensions of 737 MAX operations following the crash of Ethiopian Airlines flight ET302 on Sunday, the FAA has maintained its confidence in the aircraft.
It said in a statement on March 12 (US time) that it stood ready take action should circumstances warrant.
“The FAA continues to review extensively all available data and aggregate safety performance from operators and pilots of the Boeing 737 MAX,” the FAA said.
“Thus far, our review shows no systemic performance issues and provides no basis to order grounding the aircraft.
“Nor have other civil aviation authorities provided data to us that would warrant action.
“In the course of our urgent review of data on the Ethiopian Airlines Flight 302 crash, if any issues affecting the continued airworthiness of the aircraft are identified, the FAA will take immediate and appropriate action.”
— The FAA (@FAANews) March 12, 2019
About half of the roughly 370 737 MAX aircraft in service have been grounded following actions from regulators around the world.
There are about 70 737 MAX aircraft in service in the United States with three carriers – American Airlines, Southwest Airlines and United Airlines.
Some groups representing airline staff in the United States have called for 737 MAX operations to be suspended.
The US Association of Professional Flight Attendants (APFA), which represents flight attendants at American Airlines, said its members were very concerned following the Ethiopian Airlines accident.
APFA National President Lori Bassani called on American Airlines chief executive Doug Parker to “strongly consider” grounding the airline’s 737 MAX aircraft until a thorough investigation could be performed.
“Our flight attendants will not be forced to fly if they feel unsafe,” Bassani said in a statement.
The Transport Workers Union of America (TWU) is also pressing for the aircraft to be grounded.
In an abundance of caution, the 737 Max should be grounded until both the data and voice recorders of the recent flight have been reviewed and a determination of the two accidents using this type of aircraft have been determined. People must always be put over profits. @FAANews
— TWU (@transportworker) March 12, 2019
Country after country is grounding the @boeing 737 Max 8. When will the US move to protect its citizens? China, Brazil, Indonesia, Mexico… 19 out of 47 airlines have grounded planes. @kendallflyers @flyersrights https://t.co/1rZG6DgelL
— TWU (@transportworker) March 12, 2019
Boeing says 737 MAX safe
Boeing has defended the 737 MAX amid the wave of regulators choosing to suspend operations with the aircraft.
“Safety is Boeing’s number one priority and we have full confidence in the safety of the 737 MAX,” Boeing said in a statement on its website on March 12 (US time).
“We understand that regulatory agencies and customers have made decisions that they believe are most appropriate for their home markets.
“We’ll continue to engage with them to ensure they have the information needed to have confidence in operating their fleets.”
Further, Boeing noted that the FAA had not called for any regulator action at this time.
“And based on the information currently available, we do not have any basis to issue new guidance to operators,” Boeing said.
The investigation into the crash of the Ethiopian Airlines 737 MAX 8 minutes after it took off from Addis Ababa is in its early stages, with the flight data recorder and cockpit voice recorder only retrieved on Monday.
Media reports indicated the pilot has requested to turn back to Bole International Airport due to technical difficulties.
The accident at Addis Ababa occurred about six months after a Lion Air 737 MAX 8 plunged into the Java Sea shortly after departing Jakarta.
There were no survivors in both cases.
The US FAA said on March 11 it was too early to determine whether there were any parallels between the two accidents.
The Indonesian National Transportation Safety Committee (NTSC) preliminary report into the Lion Air incident found pilots were battling a “flight control problem” before the aircraft crashed.
The report said the aircraft had experienced airspeed indicator malfunctions on its last four flights.
In response to the accident, the United States Federal Aviation Administration (FAA) issued an emergency airworthiness directive (AD) on November 7 to operators of Boeing 737 MAX aircraft, which called on them to address procedures in the event of pilots receiving erroneous angle of attack sensor information.
“This emergency AD was prompted by analysis performed by the manufacturer showing that if an erroneously high single angle of attack (AOA) sensor input is received by the flight control system, there is a potential for repeated nose-down trim commands of the horizontal stabiliser,” the AD said.
“This condition, if not addressed, could cause the flightcrew to have difficulty controlling the airplane, and lead to excessive nose-down attitude, significant altitude loss, and possible impact with terrain.”
The AD followed Boeing issuing an operations manual bulletin (OMB) that asked 737 MAX operators to remind pilots of how to handle “erroneous” information from the aircraft’s angle of attack sensors.
The investigation has also canvassed the role of the Maneuvering Characteristics Augmentation System (MCAS) that was introduced on the 737 MAX.
The MCAS helps push the nose to reduce the risk of at the aircraft stalling in response to a high angle of attack (AOA) by tilting the horizontal stabiliser. Pilots can override the system by manually adjust the trim.
It was added to the 737 MAX’s systems following some design changes from the 737 NG, with the engines a little further forward and the nose gear a little longer.
Boeing said on March 11 (US time) it had been working with the FAA on the deployment, planning and certification of a flight control software enhancement for the 737 MAX “designed to make an already safe aircraft even safer”.
“This includes updates to the Maneuvering Characteristics Augmentation System (MCAS) flight control law, pilot displays, operation manuals and crew training,” Boeing said.
“The enhanced flight control law incorporates angle of attack (AOA) inputs, limits stabilizer trim commands in response to an erroneous angle of attack reading, and provides a limit to the stabilizer command in order to retain elevator authority.”
Boeing said it expected to deploy the software update across the 737 MAX fleet “in the coming weeks”.
Further, the manufacturer said it expected the FAA to mandate this software enhancement with an Airworthiness Directive by April.