One of the things that’s being talked about a lot in the coverage of AirAsia 8501 is the idea that under certain circumstances a commercial airliner might start to go too slow, stall, and fall out of the sky. But does that happen? I scoured by brain, did some Google searches, and asked Twitter, but I haven’t found a single case of a classic power-off stall by a commercial jet at altitude. Then again I did find some accident and incident reports that seemed germane to the case. I’m listing them below; if anyone wants to alert me to others I’d be grateful.
ANA (flight number unknown), September 6, 2011. “Two flight attendants were slightly hurt and four passengers got airsick when the All Nippon Airways Boeing 737-700 with 117 people aboard descended sharply, veered off course and went belly up over the Pacific on its way from southern Japan to Tokyo on Sept 6. ANA said Thursday that the co-pilot is believed to have mistakenly hit the rudder controls instead of the door lock to allow the pilot back in the cockpit. It said the crew managed to stabilize the plane after the co-pilot’s error and land it safely.”
Air France 447, June 1, 2009. The only true case I’ve been able to find of a commercial jet experiencing a stall at altitude and fatally crashing. The kicker is that the plane was held in the stall by a disoriented pilot.
Qantas flight 72, October 7, 2008. “While the aircraft [Airbus A330-303] was in cruise at 37,000 ft, one of the aircraft’s three air data inertial reference units (ADIRUs) started outputting intermittent, incorrect values (spikes) on all flight parameters to other aircraft systems. Two minutes later, in response to spikes in angle of attack (AOA) data, the aircraft’s flight control primary computers (FCPCs) commanded the aircraft to pitch down. At least 110 of the 303 passengers and nine of the 12 crew members were injured; 12 of the occupants were seriously injured and another 39 received hospital medical treatment.
Adam Air 574, January 1, 2007. “Scheduled domestic passenger flight operated by Adam Air between the Indonesian cities of Surabaya (SUB) and Manado (MDC) that crashed into the Makassar Strait near Polewali in Sulawesi … All 102 people on board died, the highest death toll of any aviation accident involving a Boeing 737-400. A full national investigation was immediately launched into the disaster. The final report, released on 25 March 2008, concluded that the pilots lost control of the aircraft after they became preoccupied with troubleshooting the inertial navigation system and inadvertently disconnected the autopilot.” Accident report is fascinating.
Pinnacle Airlines Flight 3701, October 14, 2004. Pilots were ferrying a Bombardier CRJ from Little Rock to Minneapolis when they decided to see if they could take the aircraft to 41,000 feet, an uncommon accomplishment in that aircraft. They set the autopilot to an aggressive climb rate, and once they reached FL410 had lost so much speed that the “stick-shaker” activated and the plane’s flight control system automatically pushed the nose down to regain speed. The pilots overrode the system by force until the engines flamed out. While trying to restart the engines, they failed to notify air traffic controllers of their problems until they were below 20,000 feet. By then it was too late. Unable to restart the engines, they crashed 2.5 miles shy of the nearest airport.
China Airlines Flight 611, May 25, 2002. An ageing 747 was en route from Taiwan to Hong Kong when the aft portion of the cabin explosively depressurized due to a faulty repair several decades before. The plane broke into four parts at 35,000 feet. “The remains of 175 of the 206 passengers aboard were recovered and identified.[17] The first 82 bodies, those of 76 passengers and 6 cabin crew, were found floating on the surface of the ocean, and were recovered by fishing vessels, the Coast Guard, and military vessels… Most of the recovered passengers in the rear of the jet were found naked, since their clothes were torn off due to the forces of explosive decompression. Most of the recovered passengers in the front of the jet (Zones A through C) still had clothes on. Of the recovered passengers, 66 were fully clad, 25 were partially clad and 50 were completely naked. Some passengers were found floating, while some remained strapped in their seats. Of the recovered passengers, 54 did not float and were not seated, 7 did not float and were still seated, 81 floated and did not decompose while 25 floated and decomposed.” A similar accident was Japan Airlines Flight 123, August 12, 1985.
China Airlines Flight 006, February 19, 1985. “On February 19, 1985, it was involved in an aircraft upset accident after the No. 4 engine flamed out. The plane rolled over and plunged 30,000 ft (9,100 m), experiencing high speeds and g-forces (approaching 5g) before the captain was able to recover from the rapid dive, and then to divert to San Francisco International Airport.”
British Overseas Airways flight 911, March 5, 1966. “Boeing 707, departed Tokyo for Hong Kong with 124 people and the cabin crew aboard. Because of the clear weather at the time, the pilot asked for and received an amendment to the scheduled flight plan that would allow his passengers an up-close view of Mt. Fuji. Shortly after the airplane began its descent toward the mountain, witnesses reported seeing the airplane trailing white vapor and shedding pieces. The witnesses also reported that they saw a large puff of vapor that came from the airplane’s vertical stabilizer and that the airplane pitched up and entered a flat spin. The witnesses further reported that the vertical stabilizer assembly and engines were missing, the outer wing had failed, the forward fuselage broke off, and the airplane continued in a flat spin until it crashed into the base of Mt. Fuji. All of the airplane occupants were killed. The report on this accident indicated that, when approaching Mt. Fuji, the airplane was violently impacted by a severe mountain wave, which led to vertical stabilizer failure and subsequent in-flight breakup. (A U.S. Navy aircraft, which was dispatched to search for the flight 911 wreckage, encountered extreme turbulence near the area of the crash. In fact, the G meter installed on the U.S. Navy aircraft registered +9 to -4 Gs during the flight.)” In a similar vein, American Airlines 587 lost its rudder and vertical stabilizer on takeoff from New York’s JFK airport on November 12, 2001, and also plunged to the ground in a flat spin. In this case the cause was overly vigorous rudder inputs by the pilot flying. The paragraph on the BOAC flight is from a footnote on page 135 of the AA587 NTSB report linked to above.
Here’s another resource: a NASA document that summerizes various incidents voluntarily reported by US pilots.
Special thanks to @goldmansachs666, @RWMann
I did some quick-and-dirty but interesting calculations to see if the reported high ROC and altitude conditions would be allowed by conserving energy without the need for an updraft. So basically,
0.5 (Vh^2 + Vv^2) + gH = constant
Where Vh is the horizontal speed, Vv is the vertical speed, H is the altitude, and g is the acceleration due to gravity.
A maneuver in which horizontal speed is traded off for vertical speed and altitude is known as “zoom-climb”, and can be used to attain vertical speeds much higher (for a short time) than can be achieved through a sustained climb.
I assumed initial level conditions of 469 knots and 32,000 ft (based on the ADS-B data) and determined the combinations of horizontal speed and altitude consistent with ROC = 9000 fpm.
The plot is shown below. The calculated curve is consistent with the conditions shown in the leaked radar plot, which are Vh = 353 knots and H = 36,300 ft.
Based on this, I conclude that an updraft is not required to reach ROC = 9000 fpm and speed instrumentation may have been properly functioning.
https://twitter.com/RadiantPhysics/status/550701838878908417/photo/1
As we all know ac accidents happen due to a combination of things, either in the cockpit, the ac, or both.
My sad money is on weather causing a flame out & wind-sheer causing a hull occurrence of some kind that was unrecoverable. With the absence of a mayday call they were just too busy trying to stay alive or too incapacitated due to a hull occurrence.
Happy New Year 2015 all!
First, I hope this year brings everyone happiness and prosperity!
Next, back to the questions:
1. Stall? Agree with C Butler, seems like news updates are pointing to this, too. Pilots likely too busy/unable to mayday.
I really hope in the near future mayday signals automate and send under certain conditions.
http://www.dailymail.co.uk/news/article-2893411/Stricken-AirAsia-plane-soared-fast-fighter-jet-dropped-vertically-Java-Sea-thrust-giant-hand-crash-experts-revealed-today.html
2. And, where is the black box ping? Apparently, they ping only up to a few miles?
http://www.bbc.com/news/magazine-26721975
A few miles doesn’t seem to cut it…
3. Where is the fuselage? Apparently, still unknown. Singapore Air Force and Navy have deployed UAV.
I hope everyone sends a few more of these. Earlier too, next time.
Since some bodies were intact and cloths not torn off and someone must have openned the door- the plane did not fall like a rock.
A recovery from stall is something seriously trained and there is a lot about it in youtube.
A stall can be recovered with or without engines, which may have shut down. If engines were off, the plane could glide and land wildly. by windmill procedure and the starter the engines could start in 30 seconds up to a minute of dive, losing 10-20,000 ft.
This may be the story of QZ8501:
http://lessonslearned.faa.gov/ll_main.cfm?TabID=1&LLID=40&LLTypeID=2
The search for MH370, under the direction of the Joint Investigation Team (JIT), has produced ZERO results.
Of far greater concern: the JIT has directed key decisions which outside investigators have shown defy logic (and in some cases, the laws of physics).
The technical concerns their decisions raise (to be summarized and published here shortly) are fully documented on this site, and on those of others connected to the so-called “Independent Group”, which has greatly assisted – and at times, been forced to LEAD – the technical analysis driving the search, despite being systematically denied answers to key questions.
On this, the 300TH DAY of the search for closure for passengers’ families, I hereby DEMAND – on those poor peoples’ behalf – that the JIT be held publicly to FULL ACCOUNT for its direction of the search.
JOIN me.
And tell two friends.
And make SURE all THREE of you make some NOISE.
Here’s a link to my Day 300 follow-up tweet re: #day200audit, in case it helps you with the noise part:
http://hope.ly/1zXssX4
@Victor – nice work. Though I don’t doubt that there are updrafts and downdrafts, I’m struggling to believe that a combination of them basically swatted the plane out of the sky at 32,000 feet. Your model makes far more sense, considering the pilot was actively trying to get to that altitude already.
In your model, does the aircraft continue flight after it reaches 41,000 feet?
@jeffwise – With Victor’s calculation in mind, I’d suggest a comparison with Pinnacle 3701. In that case, the pilots were fooling around, but the trip to a higher altitude led to engine failure which led to attempts to recover which led to the crash. Not quite a stall, but an example of how sudden altitude changes could doom a flight.
Pinnacle 3701 as I recall stalled, recovered, and stalled again.
Colgan Air Flight 3707 was not at altitude, but is relevant in the sense of wrong response to stall warning and stall.
@JS: The calculation was only to show that a high ROC beyond the performance limits of the plane can be achieved without an updraft. It’s not really an accurate dynamic model as key forces on the plane (e.g., drag and thrust) are not included. Nonetheless, I find it interesting that at the assumed altitude (36,300 ft) and ROC (9,000 fpm), the horizontal speed is close to what was measured (353 knots).
In a zoom-climb sequence, the kinetic energy from the initial speed (in this case 469 knots) is converted to potential energy in the climb. This means that regardless of the split between horizontal and vertical speed, the magnitude of the speed decreases as altitude increases, which will ultimately lead to a stall if the steep climb continues. Once the stall occurs, unless the plane is pitched down to get airflow over the wings, the plane will fall from the sky.
Victor,
You will never make it as a journalist. You are actually concerned about facts and physics.
I am very frustrated by the information coming out from the media on this incident.
1) Were any of the recovered bodies wearing PFD’s? I have read reports claiming both yes and no.
2) Were autotpsies performed to check for water in lungs?
3) Too many “experts” – some have the plane landing like a feather (no ELT signal), and some have it dropping like a rock.
4) No sign of an “Incident Command System” where there is a public information officer dispensing reliable information. We are getting dribs and drabs from a variety of people whose link to the official search is not at all clear.
I am very frustrated at this point.
Continuing from previous thread.
The QZ8501 “routine” flight change story has a hole in it.
https://twitter.com/nihonmama/status/551066998638014464
@Brock
Yes, I feel the same way. The public sector plays by a different set of rules. Accountability is not a high priority. In the private sector leaders are replaced for a lack of results. No points are awarded for trying.
If, by the end of May, nothing is found it would certainly warrant a new team. Unfortunately someone has to pay the bill. I don’t see an unlimited supply of public funding for the search effort. Taxpayers will soon say, enough is enough.
@Nihonmama
Was the revocation b4 or after the incident?
It continues to amaze me that people expect there to be an ELT transmission in the event of a crash into water. The 406Mhz ELT, mandated on most aircraft, is activated by a simple G-switch, on impact. It can also be activated by the crew by flicking on an overhead stitch – if they have the time and the presence of mind to do so. However, the first transmission from the ELT does not occur [by design] for 50 seconds after activation.
For the transmission to be radiated the cable from the ELT to the antenna and the antenna itself have to be intact. The antenna also has to be above water level. That poses a real problem with a crash into the sea.
Analysis of ELT occurrences [FAA and others] suggests that in 80% of aircraft crashes the ELT is NOT effective, for one reason or another. Why they are still mandated, and have not been superseded by more effective real-time systems beats me.
Good points on the ELT Flitzer.
Now how about the reports of the aircraft being upside down on the bottom even though it has not been located?
Another one is some bodies still strapped in seats.
Journalists have absolutely no integrity. My threshold for amazement has been stretched pretty far.
@Chria:
Gerry’s earlier tweet:
“Just heard Indo Air Asia route permit for Surabaya to Singapore has been frozen/revoked by Indo govt. Ouch!”
@Brock
I feel the same frustration about the apparent lack of thorough investigations and transparency. Concerning Malaysia being the lead investigator just think of:
– the slack reaction after secondary radar contact had been lost
– the secrecy surrounding primary radar sightings after the turn near IGARI leading to days of searching in the wrong locations
– the clunky compilation of communication recordings, and change in the citation of last received communication from mh370
– the unwillingness to release the complete, raw satellite data
– the silence surrounding the criminal investigations since early summer
– the lack of research following a report about a received distress signal
– the impotence shown by defence ministers of Malaysia and Maldives to explain the Maldives aircraft sighting
– the minimalistic preliminary report by the Chief Inspector of Air Incidents
All together this does not look very good (and I’m sure this list can be made much longer)
The Chief Inspector is obliged to compose an interim report before March 8th 2015. Can we expect something serious this time?
Moreover, other countries participating in the JIT hold a joint responsibility. Most of them have the political means to put pressure on Malaysia. So, If countries like UK, US, Australia get smeared in the process of finding out what happened as well, they should not complain. Nor should their “supporters” do. It is a logical result of the chaotic investigations and initial search efforts. Malaysia and the other investigating countries have created the poison of suspicion themselves by their misinformation, fencing and by conveniently looking away.
Is there still a way out of this impasse? I’m afraid that as things are going now, at “best” the wreckage will be found. But will this give answers to the main questions we all have?
Thanks, Niels. Since day one, I’ve been seeking TRUTH more so than WRECKAGE, as only the former will provide the closure those poor families so desperately need.
Niels, can you put me in touch with your source for that “NW Point” coordinate you posted, attributed to M. Dolan? I’m synthesizing documentation, and, in my hands, that coordinate is at best fourth-hand information (even worse, if M.Dolan is, as is now widely suspected, himself just a conduit). Thanks in advance.
@Flitzer_Flyer
Absolutely astounding that the ELT or sounding devises aren’t absolute!!! Confounding!!! I Agree!!!!
I have wondered for years about what you might call plane crash epidemiology. Sorry if these are too basic a questions for aviation geeks.
Is there an up to date document/blog/book (not a wacky web forum FAQ!), in terms accessible to the reasonably educated lay public, about the overall statistics of plane crashes and incidents?
People have been flying in jets a long time now and this makes me wonder about an old marketing(?) claim that being on a plane is one of the safest places you can be. Having made it to slightly over 40 years of age, I can conclude that I’ve spent a lot of time in safe places in my life. However, I’m really not sure which is safest. Anyway, I’ve never once heard this claim backed up with MEANINGFUL statistics, but rather a bunch of hand-waving and dubious comparisons of what amounts to little more than apples and oranges.
For example, if you look at deaths per miles-travelled of course the jet sounds safer than the car. But what if you compare deaths per trip for car vs. jet? I suspect both probabilities are both very, very small. Nevertheless, which is smaller?
Are some aircraft more likely to crash than others? With literally billions and billions of passenger flights since the days of the De Havilland Comet, it ought to be possible to mine some interesting data.
Are some (major) airlines safer than others?
Pilot error is often (conveniently? For the dead offer no rebuttals!) cited as the cause of a crash. Did the pilots who made fatal errors have any common characteristics in their backgrounds, family, health?
At what time of day are crashes most likely? One would naively assume a crew could cope better with a problem wide awake at 14:00 than zonked at 02:00….So are red-eye flights more likely to crash?
What is the most/least likely crash place (or type of place)? (Not counting near airports.)
Flitzer_Flyer: Where did you get the idea that there is a 50 second delay? My ELTs don’t have any delay.
airlandseaman: I read it somewhere else recently, but here are some quotes from the manual for my ELT:
“Do not allow test duration to exceed 5 seconds. Any time the ELT is activated it is transmitting a 121.5 Mhz distress signal. If the unit operates for approximately 50 seconds, a “live” 406 Mhz satellite distress signal is transmitted and is considered valid by COSPAS-SARSAT satellite system.”
“In the event of a crash the ELT activates automatically and transmits the standard swept tone on 243/121.5 Mhz, lasting until battery power is gone. For the first 24 hours of operation a 406Mz signal is transmitted at 50 second intervals.The transmission lasts 520 mS and contains identification data programmed into the beacon and is received by COSPAS-SARSAT satellites.”
Perhaps all ELTs do not operate in precisely this manner, but I suspect that the 406 transmission is well specified somewhere.
airlandseaman: See also the report into the search for AF447 – – – sea-search-operations-af447, published Oct 2012, page 9.
For any crash into water the ELT is practically useless. It is long past the time when ELTs operating in this manner were removed, and replaced with some real-time tracking device. In GA too.