Thursday , July 7 2022

Boeing warns of 737 maximum planes after the aircraft of Lion Air in Indonesia


Alan Levin

Washington | Boeing's warning for 737 Mac operators around the world gives the first indication of how bad data the air flow sensor data could have contributed to the deadly accident of the Indonesian airline last week.

The bulletin is combined with statements by Indonesian investigators to point out that pilots at Lion Air 737 Mak 8 fought against the airplanes as his computers commanded steep dive during their last moments of the year.

The problem occurs only when the autopilot is off, Boeing said. The Bulletin emphasized the existing procedures for correcting the aircraft when it responds to the wrong information. After the protocol it should be easy for well-trained pilots, although it may be more challenging in the heat of the moment when the equipment is faulty and the alarms sound.

US aviation regulators have said they are drafting an order requiring airlines to follow Boing's instructions. The manufacturer warned that the so-called angle sensor can provide false readings in limited circumstances that cause the 737 Mak to bend the nose down. Boing did not recommend new inspections or other actions for operators.

SilkAir's Boeing 737 Mak 8. "vidth =" 620 "/>
SilkAir's Boeing 737 Mak 8.


Previous problems


The sensor on the failed plane was replaced the day before, after it failed on a previous trip, the National Commission for Safety in Traffic reported at the briefing. A malfunction can cause airplane computers to incorrectly detect the pillars of the middle-aged airflow, leading to a sudden dive of aircraft in order to regain the speed it needs to continue to fly.

The US Federal Aviation Administration said on Wednesday that it would "take additional appropriate measures, depending on the results of the investigation". The FAA also informed regulatory counterparts around the world, who usually follow the leading US agency on security issues.

The Boeing newsletter just reminds aircraft operators that accentuate the procedures described in the checklist of pilots are given to help navigate the stabilizer problem. It is still possible that the FAA can order a planetarium in Chicago to redesign equipment or software to investigate the details of the 29 October crash that killed 189 people.

Fresh questions

New information about Lion Air Flight 610 raises more questions, researchers will want to examine pilots' action, how they trained flight crews, and whether maintenance on the system was adequate, said Roger Cock, a former NTSB researcher.

"I would definitely look at the interface of man and machine and how to pilot the answers," said Coke, a former pilot airline that flew earlier versions 737 and specializes in NTSB in the cockpit action.

One of the confusing things about the accident is that the plane was flying in the clear sky during daylight so that pilots should be able to cope with the problems they were facing with speed and wrong sensors, said Coke. However, in rare cases, accidents are caused by what investigators call the "attraction factor".

"If you do not take the appropriate action because you are surprised, you can make a serious mistake," he said.

Pilot trade union in Southwest Airlines, the largest buyer of 737 Mak, has not received any reports from its members about problems with incorrect reading of the sensors, said Jon Veaks, President of the Alliance of Pilots of Southwestern Associations.

United Technologies Corp delivers shock-sensing sensors and an indicator for 737 Mac, according to The company did not respond to comment requests. Honeivell International provides an inertial reference unit for air data.

The Lion Air boat fell into the Java Sea a few minutes after taking off from Jakarta airport, so it suddenly carried a thrust of 600 miles per hour (965 km / h) before hitting the water.

A moment earlier, pilots made a request to return to Jakarta by land, but never returned to the airport, according to the Indonesian Commission for Safety and Flight Tracking Data. The agency said that the pilots deal with a misstatement of air speed.

Boing said he fully cooperates and provides technical assistance while the investigation continues. Shares of the company grew less than 1% to $ 367.51 at 10.55 in New York. This action increased by 24 percent this year to Tuesday.

While modern jets primarily work on autopilot, a computerized system can be separated when air speed indicators do not work, which leads pilots to fly manually by plane. If Mak has an "unmodified coating of the thread carrier", pilots can avoid it by pressing the switch on their control yoke. But computer planes will continue to try to get off as soon as the switch is released, according to a Boeing newsletter announcement.

Flying crews should respect a separate protocol to stop the airborne potentially dangerous action, according to the bulletin. Pilots should remember the procedure for separating the input angles of the attack on the aircraft's computer system. Boeing delivered 219 Mack aircrafts – the newest and most advanced 737 jet aircraft – since last year's models had a commercial championship with Lion Air.

The angle sensor is designed to measure the angle between the air flow and the reference line on the wings so as to maintain the lift. If the flow is interrupted by an overflying aircraft or too fast climbing, it can cause an aerodynamic brake and balance. However, if the sensor does not work, it can cause computer planes wrongly thinking that it is in the stand – which then can command the plane to run unintendedly.

Aircraft and engine manufacturers regularly send bulletins to air carriers warning about safety measures and maintenance measures to be taken, most of which are relatively routine. But the urgency of a fatal accident may cause the notification of such a notice.

After the Southwest Airlines motorcycle was interrupted this year for Pennsylvania, killing passengers, CFM International issued more newsletters to operators of its CFM56-7B power plants. Aviation Regulators such as the US FAA and the European Aviation Safety Agency often follow such actions by mandating carriers to follow the newsletters.

Pilots lift and lower the nose of Boing's side airplanes, pushing and pulling the yoke in the cockpit, which controls the panels on the tail known as the lift. In addition, a system called "trim-tone" can be changed to encourage the movement of the nos-up or nose-down.

The role of computers

Reading the angles of an attack is entered into a computer that will in some cases attempt to throw out the nose using a tilting inclination system. In the early days of the old nozzle, the trim system with tone was associated with several accidents. If the pilots are not careful, they can cause serious settings for setting the nose that prevent leveling of the level.

While rare, similar accidents have also occurred in recent times. The issue occurred in 2016 at the Rostov-on-Don airport in Russia when FliDubai 737-800 wore and hit a steep angle, according to a previous report by Russian investigators. This case did not include the angle of attack. One of the pilots broke the plane to push his nose as he tried to climb after he stopped landing, the report said. All 62 people on board were killed.

– with Julie Johnsson in Chicago and Harry Suhartono in Jakarta

Source link