Bad plane crash in Africa -- Evaluation & Govt. Responses
- Thread starter Nitt1300
- Start date
Most that I know......the big concern for me is that the system(s) involved in the LionAir crash are individually good. Working together, on the 737max, they are problematic. The early data from the Ethiopian crash suggests similar issues. While it’s way too early to guess at the causes and contributing factors, I know enough to avoid the airframe.
So one of the American fatalities on the Ethiopian flight was a relative (grand niece) of Ralph Nader.
https://www.bostonherald.com/2019/03/13/massachusetts-native-dies-in-ethiopian-airline-crash/
https://www.bostonherald.com/2019/03/13/massachusetts-native-dies-in-ethiopian-airline-crash/
I too am watching this closely. I fly SWA a ton, in fact flew in the MAX Monday Dallas to Liberia Costa Rica. Also, it is my company that develops and maintains the CAD/CAE software used by both Boeing and Airbus. In fact we just signed a ten year $1b contact with Boeing. Although my guess the issue is with avionics/software and not structural. We shall see...
There are two things about the MAX automated system (MCAS) that are troubling and out of character for Boeing. 1) System takes control from the pilot and it's a complex, multi-stage process for the pilot to get control back. That is counter to Boeing's longtime stated philosophy that the pilot always has control and the automated system is an assistant.
2) The MCAS system can apparently be fooled by bad data from a single angle of attack sensor. That goes against the longtime design philosophy of redundancy -- no single component failure should be enough to bring down a plane.
All this was known before the Ethiopian crash so it's really tragic that Boeing and the FAA couldn't get an effective fix deployed before they lost a second aircraft. We don't know for sure whether MCAS was involved in the Ethopian crash but it looks extremely similar to the Lionair crash.
The big question for me is, why did Boeing go against its longtime design philosophy when it designed MCAS to be so hard for the pilot to override? Part of it may simply have been inadequate design/testing -- they didn't adequately deal with the bad sensor scenario.
But still, why did they design it so the system would take control from the pilot? That's so unlike Boeing, and Boeing pilots have been shocked when they found that out.
Two possible scenarios:
1) Boeing engineers were concerned about the inherent stability of the plane, especially early in flight. There are reports that flight testing found an unusual and dangerous stall condition (because of the forward position of the MAX engines) that Boeing hadn't anticipated. Maybe they did MCAS because they were afraid pilots wouldn't be able to recognize or react to the stall fast enough to save the aircraft.
Or 2) The FAA was so concerned about the stall scenario that they insisted Boeing do MCAS or they wouldn't certify the plane.
The nightmare scenario for Boeing (unlikely in my opinion, but a possibility) is that the physical design of the Max is so inherently unstable during takeoff that it isn't really safe to fly without MCAS. So if they can't revise MCAS and satisfy the safety agencies (not just the FAA, but now they have to worry about Europe and China), they could be forced to physically redesign the plane, which would mean delaying deliveries (and we're talking around 500 aircraft a year).for at least 2 years. That would be catastrophic for Boeing and have a big impact on the whole industry.
Ironically, Boeing in 2011 had wanted to do a clean-sheet 737 redesign, but then Airbus announced the A320neo re-engining and Boeing had to respond quickly or lose market share -- the Max was the result. In order to speed the timeline Boeing kept the same 737 fuselage and wing position, so the only way they could fit the engines was to mount them extra-far forward, which changes the flight characteristics.
2) The MCAS system can apparently be fooled by bad data from a single angle of attack sensor. That goes against the longtime design philosophy of redundancy -- no single component failure should be enough to bring down a plane.
All this was known before the Ethiopian crash so it's really tragic that Boeing and the FAA couldn't get an effective fix deployed before they lost a second aircraft. We don't know for sure whether MCAS was involved in the Ethopian crash but it looks extremely similar to the Lionair crash.
The big question for me is, why did Boeing go against its longtime design philosophy when it designed MCAS to be so hard for the pilot to override? Part of it may simply have been inadequate design/testing -- they didn't adequately deal with the bad sensor scenario.
But still, why did they design it so the system would take control from the pilot? That's so unlike Boeing, and Boeing pilots have been shocked when they found that out.
Two possible scenarios:
1) Boeing engineers were concerned about the inherent stability of the plane, especially early in flight. There are reports that flight testing found an unusual and dangerous stall condition (because of the forward position of the MAX engines) that Boeing hadn't anticipated. Maybe they did MCAS because they were afraid pilots wouldn't be able to recognize or react to the stall fast enough to save the aircraft.
Or 2) The FAA was so concerned about the stall scenario that they insisted Boeing do MCAS or they wouldn't certify the plane.
The nightmare scenario for Boeing (unlikely in my opinion, but a possibility) is that the physical design of the Max is so inherently unstable during takeoff that it isn't really safe to fly without MCAS. So if they can't revise MCAS and satisfy the safety agencies (not just the FAA, but now they have to worry about Europe and China), they could be forced to physically redesign the plane, which would mean delaying deliveries (and we're talking around 500 aircraft a year).for at least 2 years. That would be catastrophic for Boeing and have a big impact on the whole industry.
Ironically, Boeing in 2011 had wanted to do a clean-sheet 737 redesign, but then Airbus announced the A320neo re-engining and Boeing had to respond quickly or lose market share -- the Max was the result. In order to speed the timeline Boeing kept the same 737 fuselage and wing position, so the only way they could fit the engines was to mount them extra-far forward, which changes the flight characteristics.
I am not a pilot and don't really fly much so I have little understanding of the problems. But one 'expert' I saw said that the stall prevention system is separate from the auto pilot. The stall prevention system activates when it senses the plane is in a steep climb and brings down the nose of the plane. Sometimes it activates during normal climbs and this is the problem, thus the two crashes shortly after takeoff when they should be climbing.
And when a plane experiences flight control issues, a less trained pilot shuts off the auto pilot and expects to able to fly the plane fully manual but the stall system is still engaged. It will still over ride the manual inputs to reduce stall risks.
Better trained pilots know to turn off both systems if an issue arises. Then they can manually fly the plane. "Expert' said he was perfectly comfortable flying in a Max that is flown by US carriers/pilots that have had the proper training.
EU grounded the 737 MAX today. Lots of pressure on Boeing. Being a US company, I root for Boeing over Airbus. I hope these crashes weren't Boeing's fault. (having said that, i prefer to fly in Airbus products as, to me, the seats are more comfortable and they feel like they are quieter. Best flight I ever had was in a airbus A380 second floor.
I've flown on Frontier a few times over the last 3 three years and it was my first time on Airbus planes (A320). I found the seats to be too firm and upright and you can't adjust the seat back if you are behind row 5.
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The only thing that bothers me is that witnesses on the ground said it was smoking, making strange noises, and had debris falling off as it came done. That doesn't sound like a control problem to me.
totally agree but eyewitnesses are often the least accurate. The black box will tell the tale. (assuming the press reports it accurately)
As a previous poster said, it is up to the carrier. The seats are their thing. On United, it is clear the airbus product seats recline more....at least that is my experience.
I misspoke with organic specifically but 3000 Americans die every year from foodborn illness. 5 died from tainted lettuce last year which I had read was organic but turns out wasn’t. Point still stands. Eating lettuce killed more people in the us last year than us commercial air travel even with the deathtrap 737 max flying unrestrained.
Okay, now I'm on board. There are so many things people do without thinking every single day that are more likely to kill them than flying on this particular plane. That said, why fly on that plane if there are other planes that aren't having any known problems?
There aren’t. It’s not cost effective to have large numbers of unused aircraft sitting around. Southwest doesn’t have planes in inventory to replace the ones that are grounded
I think the nightmare scenario is that it becomes public knowledge that Boeing bribed officials to certify the plane.
Note this is speculation. But I wouldn’t be shocked.
Sure seems like there were other major problems (either human error or system) that caused the crash, even if MCAS ultimately was an issue at the end (due to the other problems)
Actually I would be quite shocked. Certifying a plane isn't some back door deal process. Way too many hands in the pot for that to have happened and word not leaked out
Piece Found At Ethiopian Airlines Crash Site Shows Jet Was Set To Dive
A screw-like device found in the wreckage of the Boeing 737 Max that crashed last Sunday in Ethiopia indicates the plane was configured to dive, a piece of evidence that helped convince U.S. regulators to ground the model, a person familiar with the investigation said late Thursday night.
Federal Aviation Administration chief Daniel Elwell on Wednesday cited unspecified evidence found at the crash scene as part of the justification for the agency to reverse course and temporarily halt flights of Boeing's largest selling aircraft. Up until then, American regulators had held off as nation after nation had grounded the plane, Boeing's best-selling jet model.
The piece of evidence was a so-called jackscrew, used to set the trim that raises and lowers the plane's nose, according to the person, who requested anonymity to discuss the inquiry.
A preliminary review of the device and how it was configured at the time of the crash indicated that it was set to push down the nose, according to the person, who wasn't authorized to speak publicly about the investigation.
The jackscrew, combined with a newly obtained satellite flight track of the plane, convinced the FAA that there were similarities to the Oct. 29 crash of the same Max model off the coast of Indonesia. In the earlier accident, a safety feature on the Boeing aircraft was repeatedly trying to put the plane into a dive as a result of a malfunction.
All 157 people aboard Ethiopian Airlines Flight 302 died early Sunday shortly after the plane took off. The pilot reported an unspecified problem and was trying to return to the airport. The plane crashed near Addis Ababa, Ethiopia's capital. The plane's crash-proof recorders have been sent to France to be analyzed.
The discovery of the jackscrew was earlier reported by NBC News.
1 COMMENT
Separately, the New York Times reported that doomed Ethiopian Airlines plane was in trouble almost immediately after takeoff as it lurched up and down by hundreds of feet at a time. The captain of the Boeing Co. 737 Max 8 asked in a panicky voice to turn back only three minutes into the flight as the plane accelerated to abnormal speeds, the newspaper reported, citing a person who reviewed the jet's air traffic communications.
A screw-like device found in the wreckage of the Boeing 737 Max that crashed last Sunday in Ethiopia indicates the plane was configured to dive, a piece of evidence that helped convince U.S. regulators to ground the model, a person familiar with the investigation said late Thursday night.
Federal Aviation Administration chief Daniel Elwell on Wednesday cited unspecified evidence found at the crash scene as part of the justification for the agency to reverse course and temporarily halt flights of Boeing's largest selling aircraft. Up until then, American regulators had held off as nation after nation had grounded the plane, Boeing's best-selling jet model.
The piece of evidence was a so-called jackscrew, used to set the trim that raises and lowers the plane's nose, according to the person, who requested anonymity to discuss the inquiry.
A preliminary review of the device and how it was configured at the time of the crash indicated that it was set to push down the nose, according to the person, who wasn't authorized to speak publicly about the investigation.
The jackscrew, combined with a newly obtained satellite flight track of the plane, convinced the FAA that there were similarities to the Oct. 29 crash of the same Max model off the coast of Indonesia. In the earlier accident, a safety feature on the Boeing aircraft was repeatedly trying to put the plane into a dive as a result of a malfunction.
All 157 people aboard Ethiopian Airlines Flight 302 died early Sunday shortly after the plane took off. The pilot reported an unspecified problem and was trying to return to the airport. The plane crashed near Addis Ababa, Ethiopia's capital. The plane's crash-proof recorders have been sent to France to be analyzed.
The discovery of the jackscrew was earlier reported by NBC News.
1 COMMENT
Separately, the New York Times reported that doomed Ethiopian Airlines plane was in trouble almost immediately after takeoff as it lurched up and down by hundreds of feet at a time. The captain of the Boeing Co. 737 Max 8 asked in a panicky voice to turn back only three minutes into the flight as the plane accelerated to abnormal speeds, the newspaper reported, citing a person who reviewed the jet's air traffic communications.
bwifan
Well-Known Member
FC: SIAP... Here is Sully's reaction from his FB page...
Captain C.B. Sully Sullenberger
17 hours ago
We do not yet know what caused the tragic crash of Ethiopian 302 that sadly claimed the lives of all passengers and crew, though there are many similarities between this flight and Lion Air 610, in which the design of the Boeing 737 MAX 8 is a factor. It has been obvious since the Lion Air crash that a redesign of the 737 MAX 8 has been urgently needed, yet has still not been done, and the announced proposed fixes do not go far enough. I feel sure that the Ethiopian crew would have tried have tried to do everything they were able to do to avoid the accident. It has been reported that the first officer on that flight had only 200 hours of flight experience, a small fraction of the minimum in the U.S., and an absurdly low amount for someone in the cockpit of a jet airliner. We do not yet know what challenges the pilots faced or what they were able to do, but everyone who is entrusted with the lives of passengers and crew by being in a pilot seat of an airliner must be armed with the knowledge, skill, experience, and judgment to be able to handle the unexpected and be the absolute master of the aircraft and all its systems, and of the situation. A cockpit crew must be a team of experts, not a captain and an apprentice. In extreme emergencies, when there is not time for discussion or for the captain to direct every action of the first officer, pilots must be able to intuitively know what to do to work together. They must be able to collaborate wordlessly. Someone with only 200 hours would not know how to do that or even to do that. Someone with that low amount of time would have only flown in a closely supervised, sterile training environment, not the challenging and often ambiguous real world of operational flying, would likely never have experienced a serious aircraft malfunction, would have seen only one cycle of the seasons of the year as a pilot, one spring with gusty crosswinds, one summer of thunderstorms. If they had learned to fly in a fair-weather clime, they might not even have flown in a cloud. Airlines have a corporate obligation not to put pilots in that position of great responsibility before they are able to be fully ready. While we don’t know what role, if any, pilot experience played in this most recent tragedy, it should always remain a top priority at every airline. Everyone who flies depends upon it.
Captain C.B. Sully Sullenberger
17 hours ago
We do not yet know what caused the tragic crash of Ethiopian 302 that sadly claimed the lives of all passengers and crew, though there are many similarities between this flight and Lion Air 610, in which the design of the Boeing 737 MAX 8 is a factor. It has been obvious since the Lion Air crash that a redesign of the 737 MAX 8 has been urgently needed, yet has still not been done, and the announced proposed fixes do not go far enough. I feel sure that the Ethiopian crew would have tried have tried to do everything they were able to do to avoid the accident. It has been reported that the first officer on that flight had only 200 hours of flight experience, a small fraction of the minimum in the U.S., and an absurdly low amount for someone in the cockpit of a jet airliner. We do not yet know what challenges the pilots faced or what they were able to do, but everyone who is entrusted with the lives of passengers and crew by being in a pilot seat of an airliner must be armed with the knowledge, skill, experience, and judgment to be able to handle the unexpected and be the absolute master of the aircraft and all its systems, and of the situation. A cockpit crew must be a team of experts, not a captain and an apprentice. In extreme emergencies, when there is not time for discussion or for the captain to direct every action of the first officer, pilots must be able to intuitively know what to do to work together. They must be able to collaborate wordlessly. Someone with only 200 hours would not know how to do that or even to do that. Someone with that low amount of time would have only flown in a closely supervised, sterile training environment, not the challenging and often ambiguous real world of operational flying, would likely never have experienced a serious aircraft malfunction, would have seen only one cycle of the seasons of the year as a pilot, one spring with gusty crosswinds, one summer of thunderstorms. If they had learned to fly in a fair-weather clime, they might not even have flown in a cloud. Airlines have a corporate obligation not to put pilots in that position of great responsibility before they are able to be fully ready. While we don’t know what role, if any, pilot experience played in this most recent tragedy, it should always remain a top priority at every airline. Everyone who flies depends upon it.
Boeing 737 Max Planes Could Take Six Months to Fix, Cost More Than $500 Million, Analysts Say
https://www.yahoo.com/finance/news/boeing-737-max-planes-could-232624030.html
https://www.yahoo.com/finance/news/boeing-737-max-planes-could-232624030.html
Everything I've read suggests some other problem with the angle of attack sensor (it was for sure a problem on the doomed LionAir flight even prior to that flight). The Ethiopian flight had problems from the start, long before any MCAS would have kicked in.
Now MCAS may have been the true "cause" of the crash, and we know Boeing is working on software changes to better communicate MCAS stuff to the pilots, but it seems like it was the faulty inputs to the MCAS that caused MCAS to kick in when it shouldn't have.
Now MCAS may have been the true "cause" of the crash, and we know Boeing is working on software changes to better communicate MCAS stuff to the pilots, but it seems like it was the faulty inputs to the MCAS that caused MCAS to kick in when it shouldn't have.
Flew on the MAX on SWA Monday from PIT to HOU. Brand new and a great plane. Then the FAA stepped in and grounded them when, Wednesday? Back from Hobby today on a 737-700.
I wanted to buttonhole a Captain or FO and ask what they thought but didn't get the opportunity.
For the pilots out there - let's say you're type rated on a 737-700. Does that count for the -800 or the MAX? Or is there a separate type rating?
I wanted to buttonhole a Captain or FO and ask what they thought but didn't get the opportunity.
For the pilots out there - let's say you're type rated on a 737-700. Does that count for the -800 or the MAX? Or is there a separate type rating?
Interesting that the plane was approximately twice the normal takeoff speed. The Max has over sized engines on it, so maybe the crew over powered them in the roll out. That would indicate an inexperienced (for this plane) crew.
Don't know how much affect that very high takeoff speed would have on the MCAS system but I assume it be substantial. A steep take off angle climb at those speeds might have tripped a stall warning in the MCAS.
The B737 type rating applies to all variants of the 737. This includes the 737-200 (which had sreaight jets), the 737-3/4/500, the 737 next generation 7/8/900 which have turbofans and the 737 max family which have different engines and a longer nose gear. The MCAS system was installed to mitigate some of the issues caused by the new engines’ size, power and location. The system is not functional during operations with the autopilot engaged or when the flaps are deployed.
Thanks for the info! Appreciate it!
So on an airline like SWA which flies ONLY 737's, then any pilot - any plane - any route - any time?
That’s correct. It’s also exactly the reason that Boeing has not scratched the 737 program in favor of a replacement airframe.....Someone wants to maintain fleet commonality.
Deadhead pilot on same Ethiopian plane saves the plane from crashing the day before.
https://www.yahoo.com/news/pilot-hitched-ride-saved-doomed-053511780.html
https://www.yahoo.com/news/pilot-hitched-ride-saved-doomed-053511780.html
"The Indonesia safety committee report said the plane had had multiple failures on previous flights and hadn’t been properly repaired."
This point isn't highlighted enough.
This point isn't highlighted enough.
bwifan
Well-Known Member
The captain was at the controls of Lion Air flight JT610 when the nearly new jet took off from Jakarta, and the first officer was handling the radio, according to a preliminary report issued in November.
Just two minutes into the flight, the first officer reported a "flight control problem" to air traffic control and said the pilots intended to maintain an altitude of 5,000 feet, the November report said.
The first officer did not specify the problem, but one source said airspeed was mentioned on the cockpit voice recording, and a second source said an indicator showed a problem on the captain's display but not the first officer's.
The captain asked the first officer to check the quick reference handbook, which contains checklists for abnormal events, the first source said.
For the next nine minutes, the jet warned pilots it was in a stall and pushed the nose down in response, the report showed. A stall is when the airflow over a plane's wings is too weak to generate lift and keep it flying.
The captain fought to climb, but the computer, still incorrectly sensing a stall, continued to push the nose down using the plane's trim system. Normally, trim adjusts an aircraft's control surfaces to ensure it flies straight and level.
"They didn't seem to know the trim was moving down," the third source said. "They thought only about airspeed and altitude. That was the only thing they talked about."
The pilots of JT610 remained calm for most of the flight, the three sources said. Near the end, the captain asked the first officer to fly while he checked the manual for a solution.
About one minute before the plane disappeared from radar, the captain asked air traffic control to clear other traffic below 3,000 feet and requested an altitude of "five thou", or 5,000 feet, which was approved, the preliminary report said.
As the 31-year-old captain tried in vain to find the right procedure in the handbook, the 41-year-old first officer was unable to control the plane, two of the sources said.
The flight data recorder shows the final control column inputs from the first officer were weaker than the ones made earlier by the captain.
"It is like a test where there are 100 questions and when the time is up you have only answered 75," the third source said. "So you panic. It is a time-out condition."
The Indian-born captain was silent at the end, all three sources said, while the Indonesian first officer said "Allahu Akbar", or "God is greatest", a common Arabic phrase in the majority-Muslim country that can be used to express excitement, shock, praise or distress.
French air accident investigation agency BEA said on Tuesday the flight data recorder in the Ethiopian crash that killed 157 people showed "clear similarities" to the Lion Air disaster. Since the Lion Air crash, Boeing has been pursuing a software upgrade to change how much authority is given to the Maneuvering Characteristics Augmentation System, or MCAS, a new anti-stall system developed for the 737 MAX.
The cause of the Lion Air crash has not been determined, but the preliminary report mentioned the Boeing system, a faulty, recently replaced sensor and the airline's maintenance and training.
On the same aircraft the evening before the crash, a captain at Lion Air's full-service sister carrier, Batik Air, was riding along in the cockpit and solved the similar flight control problems, two of the sources said. His presence on that flight, first reported by Bloomberg, was not disclosed in the preliminary report.
The report also did not include data from the cockpit voice recorder, which was not recovered from the ocean floor until January.
Just two minutes into the flight, the first officer reported a "flight control problem" to air traffic control and said the pilots intended to maintain an altitude of 5,000 feet, the November report said.
The first officer did not specify the problem, but one source said airspeed was mentioned on the cockpit voice recording, and a second source said an indicator showed a problem on the captain's display but not the first officer's.
The captain asked the first officer to check the quick reference handbook, which contains checklists for abnormal events, the first source said.
For the next nine minutes, the jet warned pilots it was in a stall and pushed the nose down in response, the report showed. A stall is when the airflow over a plane's wings is too weak to generate lift and keep it flying.
The captain fought to climb, but the computer, still incorrectly sensing a stall, continued to push the nose down using the plane's trim system. Normally, trim adjusts an aircraft's control surfaces to ensure it flies straight and level.
"They didn't seem to know the trim was moving down," the third source said. "They thought only about airspeed and altitude. That was the only thing they talked about."
The pilots of JT610 remained calm for most of the flight, the three sources said. Near the end, the captain asked the first officer to fly while he checked the manual for a solution.
About one minute before the plane disappeared from radar, the captain asked air traffic control to clear other traffic below 3,000 feet and requested an altitude of "five thou", or 5,000 feet, which was approved, the preliminary report said.
As the 31-year-old captain tried in vain to find the right procedure in the handbook, the 41-year-old first officer was unable to control the plane, two of the sources said.
The flight data recorder shows the final control column inputs from the first officer were weaker than the ones made earlier by the captain.
"It is like a test where there are 100 questions and when the time is up you have only answered 75," the third source said. "So you panic. It is a time-out condition."
The Indian-born captain was silent at the end, all three sources said, while the Indonesian first officer said "Allahu Akbar", or "God is greatest", a common Arabic phrase in the majority-Muslim country that can be used to express excitement, shock, praise or distress.
French air accident investigation agency BEA said on Tuesday the flight data recorder in the Ethiopian crash that killed 157 people showed "clear similarities" to the Lion Air disaster. Since the Lion Air crash, Boeing has been pursuing a software upgrade to change how much authority is given to the Maneuvering Characteristics Augmentation System, or MCAS, a new anti-stall system developed for the 737 MAX.
The cause of the Lion Air crash has not been determined, but the preliminary report mentioned the Boeing system, a faulty, recently replaced sensor and the airline's maintenance and training.
On the same aircraft the evening before the crash, a captain at Lion Air's full-service sister carrier, Batik Air, was riding along in the cockpit and solved the similar flight control problems, two of the sources said. His presence on that flight, first reported by Bloomberg, was not disclosed in the preliminary report.
The report also did not include data from the cockpit voice recorder, which was not recovered from the ocean floor until January.
""They didn't seem to know the trim was moving down," the third source said. "They thought only about airspeed and altitude. That was the only thing they talked about.""
So poor maintenance of the plane led to MCAS kicking in when it shouldn't have, and poor piloting cause the pilots to not recover correctly
So poor maintenance of the plane led to MCAS kicking in when it shouldn't have, and poor piloting cause the pilots to not recover correctly
That may very well be what Boeing would suggest. I tend to think that poor design coupled with withholding systems information from the flight crews is what led to the accident.
Stop....Look at the planes data hard to imagine it was terrorism. There were vertical speed issues before the crash which does sound like the same issue the last 737 max 8 had.
Change to 737 MAX controls may have imperiled planes, experts say
Business
Explainer: Change to 737 MAX controls may have imperiled planes, experts say
Reuters 21 hours ago
By Alwyn Scott and Eric M. Johnson
NEW YORK/SEATTLE (Reuters) - Much like tapping the brake pedal in a car to disengage cruise control, a sharp tug on the controls of older models of Boeing Co's 737 used to shut off an automatic trim system that keeps the plane flying level, giving the pilot control.
But Boeing disabled the "yoke jerk" function when it brought out the 737 MAX, the latest version of its top-selling jet - and many pilots were unaware of the change, aviation experts told Reuters.
The difference may help explain why pilots struggled to keep their aircraft climbing after takeoff on two fatal 737 MAX flights less than five months apart that killed 346 people.
Pilots of a Lion Air flight that crashed in October scoured a handbook for answers as the plane repeatedly lurched downward in the first minutes of flight, Reuters reported.
An Ethiopian Airlines flight that went down on March 10 showed "clear similarities" to the Lion Air accident, aviation authorities said after seeing black-box data.
A pair of switches on the centre console between the pilots will turn off the automatic trim and a mechanism, new on the 737 MAX, known as the Maneuver Characteristics Augmentation System, or MCAS, that is suspected of playing a role in both disasters.
TRAINING MATERIAL 'NOT CLEAR'
But pilots would have needed to know that MCAS existed, that it had unusual power to force the plane down and that "a hard pull on the yoke" would no longer turn off the automatic trim that uses MCAS, John Hansman, an aeronautics professor at MIT, said in an interview.
"That wasn't clear to the pilots flying the airplane," Hansman said. "The training material was not clear on that."
Boeing declined to comment. In the aftermath of the Lion Air crash, Boeing pointed to long-established procedures that pilots could have used to handle a malfunction of the anti-stall system, regardless of whether the pilots knew MCAS existed.
That checklist tells pilots to switch off the two stabilizer trim cutout switches on the central console, and then to adjust the aircraft's stabilizers manually using trim wheels.An American Airlines flight manual mentions MCAS only in a table of acronyms, according to an October 2018 edition of the 1,400-page book seen by Reuters. Pilots have raised questions about why more detail on MCAS was not included.
The American Airlines manual's two-page description of trim controls describes a "trim circuit," but not how MCAS could be triggered by a faulty sensor reading, which is also suspected in the two crashes.
PREVENTING A DANGEROUS STALL
The MCAS system was designed to counteract the effect on the plane's handling caused by new larger 737 MAX engines, which had to be placed farther forward and higher on the wings because the 50-year-old 737 design sits relatively low to the ground. That move gave the MAX a tendency to nose up into a stall, a dangerous position in which a plane loses lift as too little air flows across its wings.
MCAS, essentially a few lines of computer code in the flight control system, relies on data from two small, blade-shaped sensors near the nose of the aircraft that measure the angle of air flow. Faults in the sensors are not uncommon, and MCAS relies on only one sensor at a time during flight. In the Lion Air crash, investigators found a faulty reading led the plane's computer to believe it was stalled and to push the nose down.
Boeing later issued a bulletin reminding pilots how to respond to such a faulty reading. An optional warning light could have alerted pilots to the faulty sensor.
MAINTENANCE, TRAINING UNDER SCRUTINY
Investigators unravelling the Lion Air crash are looking at maintenance records and whether the pilots had enough training to handle the emergency, among other factors.
The 737 MAX can fly without MCAS, so the feature was not considered "flight-critical" even though it has extraordinary power to steer the plane, said an industry expert with knowledge of the system who spoke on condition of anonymity. MCAS controls the large horizontal wing on the plane's tail known as the stabilizer, while the pilot controls smaller flaps or "elevators" on the stabilizer.
Over several minutes, the stabilizer can shift position enough that the elevator controls can no longer counteract the downward direction of the plane, the source said.
"They gave more control power to the automation than to the pilot," the source said of the MCAS design.
The Lion Air pilots flew for about five minutes by using the elevator to counteract the stabilizer every 15 or 20 seconds, said Hansman, based on readings from the flight data recorder. After that, the pilot tried pulling back hard on the controls.
"That's what suggests that the crew didn't understand the system. They thought they were shutting MCAS off and didn't," Hansman said. "Whereas any time during the entire sequence, they could have reached to the middle console and just shut it off."
https://www.yahoo.com/finance/news/explainer-change-737-max-controls-155949868.html
Business
Explainer: Change to 737 MAX controls may have imperiled planes, experts say
Reuters 21 hours ago
By Alwyn Scott and Eric M. Johnson
NEW YORK/SEATTLE (Reuters) - Much like tapping the brake pedal in a car to disengage cruise control, a sharp tug on the controls of older models of Boeing Co's 737 used to shut off an automatic trim system that keeps the plane flying level, giving the pilot control.
But Boeing disabled the "yoke jerk" function when it brought out the 737 MAX, the latest version of its top-selling jet - and many pilots were unaware of the change, aviation experts told Reuters.
The difference may help explain why pilots struggled to keep their aircraft climbing after takeoff on two fatal 737 MAX flights less than five months apart that killed 346 people.
Pilots of a Lion Air flight that crashed in October scoured a handbook for answers as the plane repeatedly lurched downward in the first minutes of flight, Reuters reported.
An Ethiopian Airlines flight that went down on March 10 showed "clear similarities" to the Lion Air accident, aviation authorities said after seeing black-box data.
A pair of switches on the centre console between the pilots will turn off the automatic trim and a mechanism, new on the 737 MAX, known as the Maneuver Characteristics Augmentation System, or MCAS, that is suspected of playing a role in both disasters.
TRAINING MATERIAL 'NOT CLEAR'
But pilots would have needed to know that MCAS existed, that it had unusual power to force the plane down and that "a hard pull on the yoke" would no longer turn off the automatic trim that uses MCAS, John Hansman, an aeronautics professor at MIT, said in an interview.
"That wasn't clear to the pilots flying the airplane," Hansman said. "The training material was not clear on that."
Boeing declined to comment. In the aftermath of the Lion Air crash, Boeing pointed to long-established procedures that pilots could have used to handle a malfunction of the anti-stall system, regardless of whether the pilots knew MCAS existed.
That checklist tells pilots to switch off the two stabilizer trim cutout switches on the central console, and then to adjust the aircraft's stabilizers manually using trim wheels.An American Airlines flight manual mentions MCAS only in a table of acronyms, according to an October 2018 edition of the 1,400-page book seen by Reuters. Pilots have raised questions about why more detail on MCAS was not included.
The American Airlines manual's two-page description of trim controls describes a "trim circuit," but not how MCAS could be triggered by a faulty sensor reading, which is also suspected in the two crashes.
PREVENTING A DANGEROUS STALL
The MCAS system was designed to counteract the effect on the plane's handling caused by new larger 737 MAX engines, which had to be placed farther forward and higher on the wings because the 50-year-old 737 design sits relatively low to the ground. That move gave the MAX a tendency to nose up into a stall, a dangerous position in which a plane loses lift as too little air flows across its wings.
MCAS, essentially a few lines of computer code in the flight control system, relies on data from two small, blade-shaped sensors near the nose of the aircraft that measure the angle of air flow. Faults in the sensors are not uncommon, and MCAS relies on only one sensor at a time during flight. In the Lion Air crash, investigators found a faulty reading led the plane's computer to believe it was stalled and to push the nose down.
Boeing later issued a bulletin reminding pilots how to respond to such a faulty reading. An optional warning light could have alerted pilots to the faulty sensor.
MAINTENANCE, TRAINING UNDER SCRUTINY
Investigators unravelling the Lion Air crash are looking at maintenance records and whether the pilots had enough training to handle the emergency, among other factors.
The 737 MAX can fly without MCAS, so the feature was not considered "flight-critical" even though it has extraordinary power to steer the plane, said an industry expert with knowledge of the system who spoke on condition of anonymity. MCAS controls the large horizontal wing on the plane's tail known as the stabilizer, while the pilot controls smaller flaps or "elevators" on the stabilizer.
Over several minutes, the stabilizer can shift position enough that the elevator controls can no longer counteract the downward direction of the plane, the source said.
"They gave more control power to the automation than to the pilot," the source said of the MCAS design.
The Lion Air pilots flew for about five minutes by using the elevator to counteract the stabilizer every 15 or 20 seconds, said Hansman, based on readings from the flight data recorder. After that, the pilot tried pulling back hard on the controls.
"That's what suggests that the crew didn't understand the system. They thought they were shutting MCAS off and didn't," Hansman said. "Whereas any time during the entire sequence, they could have reached to the middle console and just shut it off."
https://www.yahoo.com/finance/news/explainer-change-737-max-controls-155949868.html
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