There’s been little information out of China with regard to the China Eastern 737 that crashed last week, but from what we do know, we have some possibilities to include and exclude from consideration.
If you are considering booking travel or signing up for a new credit card please click here. Both support LiveAndLetsFly.com.
If you haven’t followed us on Facebook or Instagram, add us today.
What’s Known About China Eastern Flight 5735
There’s very little known about the crash of China Eastern flight 5735. It was operating a routine flight between Kunming and Guangzhou, the airline’s hub near the southeastern border with Hong Kong. The 737-800 (NG – New Generation) was carrying 123 passengers and nine crew members according to sources when it dramatically lost altitude from 29,100 feet (cruising) plunging into a mountainside below.
A purported video of the crash showed a vertical spire diving toward the mountainside resulting in an explosion and plume of smoke.
Data from flight trackers showed the aircraft appeared to recover around 7,000-9,000 feet before shortly thereafter continuing its fatal drop. The black box has been recovered and because the aircraft was manufactured in the United States, federal investigators will join the effort to understand what caused the crash along with Chinese teams.
The granular ADS-B data from @flightradar24 shows that #MU5735 may have actually regained control after an initial nosedive before going nose down once more and impacting the ground https://t.co/X0zSzSU6TR
— Jason Rabinowitz (@AirlineFlyer) March 21, 2022
At the time of publication, neither a recording of communications with air traffic control (ATC) nor a transcript was available.
Some Possibilities
Many have speculated about the cause of the crash and as someone who has followed aviation and subsequently, air crash investigations, some early possible causes seem to be guesses. I don’t have any inside information, but there are some speculations that seem less credible than others for a few reasons.
Mid-Air Break Up
One of the notions forwarded was that there was some sort of a mid-air breakup of the aircraft that caused it to fall from the sky. One reason that this theory would have legs is if there is a lack of direct communication with ATC. We don’t know that at this time. The other plausible reason is because aircraft pieces were found separate from the incinerated wreckage.
Why I feel this is unlikely is that noted recovery. If the plane was split apart in the air there wouldn’t be a recovery, just a straight drop from the sky and likely in several pieces, (more than has been demonstrated in the media) with a range of debris. That said, it’s also possible that the data showing a recovery was wrong.
Images appeared to show the winglet and part of the wing had sheered off and remained intact away from the crash site, and while the video is low quality, it’s hard to make out a vertical stabilizer (tail) in the video. That suggest that something happened to separate those parts, but a drop at of that magnitude could have had the same result.
Terrorism/Hijacking
Typically in a terrorism and hijacking situation, there is generally something as simple as a squawk 7500 code which indicates “Unlawful interference” such as either of these events or a simple 7700 which just demonstrates an emergency and is used more generally.
That’s not to say that something couldn’t have happened before the pilots had a chance to indicate this, but there was some sort of control briefly at the 7,000-9,000′ elevations so even with a struggle where control was regained temporarily, this wasn’t indicated. The problem with dismissing it based on the lack of a squawk 7500 or 7700 are two-fold. First, it’s possible that the pilots did indicate this but it didn’t function properly, the second is that in an air emergency the order of priorities shifts to “aviate, navigate, communicate.” The brief control period may demonstrate that they were still attempting to navigate.
The media was clear that there was no known “Mayday” distress call, so it seems unlikely even in a perilous dive, that this wouldn’t have come through from one of the two pilots.
Software/MCAS
The Boeing 737 is the most prolific aircraft ever produced. This particular model was a 737-NG ruling out a resurgence of the MCAS software that brought down aircraft in both Ethiopia and Indonesia that was found responsible for 737-MAX crashes. This plane was not equipped with MCAS and didn’t have any of the struggles with software that appeared to demonstrate a tug-of-war with the computers that other crashes have had.
Suicide/Pilot Health
An intentional downing of the aircraft by one or both of the pilots is possible. The protocol has changed since German Wings 9525 in which the co-pilot who had been treated for suicidal thoughts, locked out the captain and crashed the plane into a mountain. If both pilots were suicidal or the protocol to leave a flight attendant in the cockpit when one goes to the restroom wasn’t followed, then this is a possible cause.
This cause would explain a limited recovery of the aircraft (if there was a struggle) and the entire nose-down attitude of the plane at impact.
It should be noted as well that this possibility also explains another data point which is that the aircraft appears to be pushed or directed down rather than simply falling. This is again from the attitude but also from the rate of falling which appears to exceed the natural rate of descent from objects at that height reaching the ground in a freefall. Oddly, the speed fluctuations are also odd.
One question that remains was how a piece of the plane was then found away from the wreckage, but pushing a plane intentionally to the ground at that rate of speed could have sheered off pieces of the plane that couldn’t handle the stress.
Bad Data
Many prognosticators are focused on the recovery as I too have noted. It’s entirely possible that recovery never occurred. If the plane had encountered some sort of catastrophic failure at altitude, the reliance on flawed equipment is questionable. If ground radar detected the recovery as well, then this possibility is eliminated, but for now, it has to be at least possible that the preliminary data is bad and that leads to false assumptions.
Mechanical Issue
There have been just 11 fatal incidents out of 7,000+ 737-NGs in service. Unlike wide-body aircraft which may only fly once or twice daily, these workhorse aircraft are used on shorter flights resulting in far more take-offs and landings every day. Far more wear and tear on the equipment leads to greater chances of a mechanical problem.
This particular aircraft was manufactured in 2015 and is considered relatively new as most aircraft remain in service for 20+ years. That said, mechanical issues can happen based on something that took place on the ground, over time, or encountered in-flight. Maintenance records will be scrutinized in the coming weeks, months, and maybe years to determine the direct cause.
Rapid Decompression
One concept that’s not being discussed enough (from my estimation) is the altitude at which the plane appeared to temporarily regain control. In a rapid decompression event, one of the first orders of business is to get below 10,000 feet where passengers can easily breathe without the need for oxygen pumped from the plane’s systems.
If there had been a rapid decompression of some sort, the rapid descent, (negative vertical speed in excess of 20,000 feet/minute) would have been egregious, but it’s possible that if there had been something that caused the plane to lose pressure, the pilots may have been trying to get under 10,000 feet for this purpose initially, but the issue that caused the decompression remained and the aircraft became unmanageable as a result of the drop.
Conclusion
It’s impossible to know what caused this crash initially. Even with transcripts or recordings from the cockpit and ATC, the information could prove to be incorrect or flawed as could the data. Investigations of this nature can take years to resolve. However, key data points (a mostly intact debris field and a recovery at 7,000-9,000 feet) make this crash particularly beguiling.
What do you think? Do you have any thoughts of what could have caused this accident? What do you make of the data points?
With all due respect until the black boxes are opened and examined articles with “possibilities” and their authors should exercise decorum as they only serve to create or excel rumors / unfounded theories. While I agree planes just don’t fall out of the sky we need to wait as of this posting they have found the second box which should give us a mush better picture on what exactly happened up there. by the by my “name” is my old call sign in the usaf
@Ghostrider5408 – I agree that we shoudn’t make any firm conclusions. Some news stories are postulating some of these theories as most likey and I am trying to pose counterpoints to them, the mid-air breakup being the most egregious in my eyes.
In my opinion, the second most likely cause is not in the article. That cause is malfunction in the horizontal tail or rudder. That could send a plane diving, unlike engine failure, which tends to send a plane gliding down. Still number one on my list is intentionally bad airmanship.
@Derek: All valid points. I did mention that I couldn’t see a tail in the final dive video so I agree that could be a part of the picture. The latter is one we agree on.
The Chinese found the 2nd black box. We’ll see.
Another possibility is the horizontal stabilizer jackscrew assembly may have broke. There is also a real danger of what happened with Germanwings and maybe happened with MH 370. If the public can’t be trusted to govern itself, those select few who do govern can be trusted less. Locks on the cockpit door are dangerous as one unhinged pilot can cause a crash. Passenger needs to be able to access the cockpit in case something like that happens. There are enough passengers who would step in post 9/11 and fight anyone trying to do something malicious before they do.
Certainly, pilot error or a pilot’s failure to adequately respond to an event is the likely cause of any crash. It’s true what they say about U.S./Canadian/European training and the average demographic of pilots compared to those elsewhere. The safety record in these countries is good. A lot of the training is subpar in Asian/African/ME countries. Japan is the exception as we all know with everything (cleanliness and service). The U.S. has been very lucky since 2009 with Commercial aviation. The area that’s the problem here are all the private aviation crashes with props. I wouldn’t fly one without a BRS like the SR22.
Good point about Japan Jackson. And I wouldn’t drink water at a Mac Donalds unless you were on staff
Let’s not forget Singapore.
Decompression sounds to me rather plausible. Something was bad enough that caused pilots try and reach 10k altitude really really fast. Maybe they panicked. The rapid descent was successful, but caused some structural damage that crashed the plane.
Of course it’s mere speculation, that IMO matches the facts relativity well.
Another, is a phenomena called “Jet-Upset” typically caused by severe clear air turbulence or convective turbulence at high altitudes. If the airplane is at it’s max-weight-for-altitude and encounters this, it can happen quickly. Airlines train their pilots and dispatchers about this and have charts (low speed – high speed stall charts) to assist avoiding this heavy-high altitude exposure if turbulence is expected or forecast. If abrupt and severe it can quickly aerodynamically stall a jet airliner into a loss-of-control situation. This has happened many times in the jet age and over time the industry has learned to avoid this.
If memory serves me the last know “jackscrew” was Alaska Air MD 80 coming out of Mexico for SEA.
As to your potentials both the CVR and FDR have now been found. The FDR has been reported as being mostly in- tact. I think we will find out very soon what occurred as something so instant as this should be pretty clear in the data.
1, Mid-Air breakup. It is possible in relation to the issue with Pickle Forks that are being discussed regarding this crash. There have been past issues with 737NG’s in regards to this with inspections carried out worldwide as a result. If China Eastern did not perform these correctly it’s possible that the wing separated. The piece found miles away was the trailing edge of the winglet. However, given the G forces experienced from the rapid fall there is also a likelihood that the aircraft started breaking up as a result of and not a cause of.
2. Suicide. While it seems suspicious, the one area I didn’t see you mention is that there were actually three pilots in the cockpit that day. One was there for training/observation. This would put the suicide aspect as being far less likely. Further, as they were about to initiate the descent it is also less likely that two of the three pilots would have left the cockpit at that precise time. Lastly, a pilot wishing to purposefully take the plane down would certainly not choose a day when there were three in the cockpit.
3. Rapid Decompression. Hardly imagine this in relation to a sudden and violent vertical descent. Even in a rapid but controlled scenario to get to 10K feet the descent would be far less than what they experienced. Further, associating this to the idea that there was no communication to ATC of a problem and the F/O had over 35K hours of flying and I am sure was well trained in a controlled descent. Even in the Payne Stewart crash, though everyone seemed to be unconscious rapidly, the plane kept flying on its own until fuel was exhausted.
4. I am having trouble believing the recovery data at what I have read was around 10K feet. I just can’t imagine given the catastrophic descent prior that there was some sort of leveling off for a few seconds. I guess it’s possible, but even my lay understanding from the comments of pilots I read on this makes it seem pretty remote as to being correct in recovering an aircraft so violently falling prior. The G-forces up to that point would lead one to believe that few were even conscious.
5. Some in the comments mentioned the rudder. That issue was exclusive to earlier generation of 737’s up to and including the -500 series. There have never been reports of rudder issues with the NG’s.
I think what has intrigued everyone on this crash is that planes just don’t fall from the sky with such sudden intensity and from what was essentially the cruise altitude. The only similar being SilkAir which was believed to be pilot suicide given both the CVR and FDR were shut off prior. But the fact that there were THREE pilots on the flight deck for China Eastern makes this very remote.
My personal feeling is that very soon it will come out given the recorders being found. If they were discovered to be shut off manually than we can pretty much assume it was pilot suicide. If not, it should reveal something. My personal opinion is that this will be none of the things everyone is speculating on (including me) and a complete surprise never imagined. As in most of these investigations it might also reveal a series of issues that quickly compounded in seconds.
Stuart:
1. I agree on the rapid descent as when the pieces separated, but disagree with it occurring at height without knowing more. The limited debris field is the reason I discount that theory.
2. I hadn’t seen the check pilot so I would discount my own postulation assuming this new detail is true. That said, out of three pilots, one would have thought that the extra two hands would have been able to assist greater. It must have been terrifying and unworkable.
3. It’s possible that they simply couldn’t get hold of the situation until they reached just under 10,000 feet and the number was purely coincidental. It’s also possible that either the situation was so dire, or it was overreacted to in such a way that the primary dive was simply too sharp. The 10,000 feet number could just a data point, it isn’t as though they stopped at 10k and resumed normal flying for very long, they hit somewhere over 7k then climbed back to nearly 10k, so it could be a moot point, but the coincidence is something to consider. To your point about the Paine Stewart incident, there was another crash on Helios 522 (737-500) whereby the entire cabin (save one person) had succumbed to hypoxia and it continued to cruise at altitude until it’s crash (if you’re not familiar with this one look up the Air Investigation episode) into the Greek countryside.
4. We agree that the data may have been flawed and I have found few reports that put that forward as a possibility, it must be considered.
5. I too mentioned the vertical stabilizer simply because I couldn’t make it out in the video but to my knowledge it wasn’t found separate from crash site, so that would suggest it was attached at impact, unlike aspects of the wing.
We will see what the government issues in terms of transparency around this, I am glad that NTSB investigators are now able to participate, but I don’t have total confidence that we will know all there is to know, and with other current events around the world, I significantly doubt public outcry and demand would be enough to ensure we find out all of the facts available.
A fact check by USA Today indicates the video was from a simulation, not China Eastern Flight 5735. Among other things it says that the colors on the plane were wrong (I have not checked this myself). Without the video, we are left with the altitude data which indicates a rapid decent. I’ve seen speculation that said the aircraft approached the speed of sound. If that happened, tremendous stress was put on the airframe and control surfaces. That would also likely be the case if a stall caused the rapid drop. Pulling out of such a drop too rapidly could also cause more damage. The way I see it, the pilots may have been able to regain control but the recovery was short lived as the damage caused secondary failures shortly afterward. Hopefully the second flight data recorder will add more information to what happened.
The flight profile – which is all we’ve got at the moment – looks very like a BEA crash where explosive decompression on the rear bulkhead wrecked the tail’s control surfaces and sent it into a death dive.
Oh, and MH370 was totally a ghost flight, nothing else.