Why did Mentour Aviation take down video?

The Mentour Aviation YouTube videos, site, and Apps have gone from strength to strength, explaining to wannabe pilots and others all aspects of flying down to minor details such as why pilots pause for a moment at medium thrust before engaging takeoff thrust on departure.

It gave the impression the animator was a pilot working as captain on a small airline based in Spain.

Knowing that the airline flew Boeing 737s it came as a pleasant surprise that on a flight to holiday in Thailand with his young son on Qatar Airways where the first leg to the Middle East was on the Airbus A350 and the second on the Boeing 787 he dared say that he liked both aircraft but if anything he preferred the A350, perhaps because of the wider diameter of the cabin. He was not saying anything that would deter people flying on the 787.

Sadly this was followed by a video saying flying the route the opposite way starting with the 787 made him think differently. That was OK, but the rehashing and rehashing of features such as the auto-darkening windows to make the 787 look better seemed over the top.

I would not have thought any more about this blip except that he took down a video on the 737 MAX after a few hours not realizing the impact it would have.

[UNDER CONSTRUCTION – more coming]

737 MAX — Why was MCAS programming (apparently) so pernicious?

The revelation that it was not the pilots of the  Lion Air flight prior to the one that crashed in Indonesia who saved them (by killing off the trim circuits), but an extra pilot deadheading in the jump seat suggests there must be something pernicious in the programming making resolution by pilots on their own difficult.

The answer could lie in the fact that the impact of the program is incremental–something that the FAA people and overseas authorities never knew.

The effect on the trim was believed to be 0.6 degrees maximum.  However, it was compound, in that at each juncture a further 0.6 degrees was added until an incredible maximum of 2.5 degrees was reached.

From an official certifications (both for FAA technical people and abroad), this would not have been acceptable, especially with reference to a single angle of attack sensor.

FOR THE PILOTS at the coalface the insidious incremental nature of the trouble would easily catch them unawares because:

First there would only be small nose-down inputs with which he or she would be sure they would be able to cope.

It would then gradually become more and more difficult though seeming still quite possible deal with.

Then without time to think about the need to kill the trim circuits (according to training for runaway trim), maximum downward trim would apply and the aircraft would be plunging, with the pilots too desperate in the remaining seconds to think. Hence the value of a third person.

If the MCAS program had applied the full down trim at the beginning the pilots would have had more time and height to deal with it. On the other hand why allow such extreme downward trim without double checks it is required?

Qantas ON-TIME record

Being interested in ultra-long-haul flights I followed QF9 and found in some cases Qantas flights listed on arrivals boards and Flightradar24 would disappear or be marked as “no info”, only to arrive much later “on time“.

For instance, on March 2, the first leg of QF9 from Melbourne to Perth was delayed by some three (3) hours, and was duly marked “delayed”.

However, the onward leg from Perth to London was then rescheduled for departure more than three hours later and marked as being on-time.

I thought Qantas’s top ranking could–like its perfect safety record–partly be attributed to the nature of the routes flown. US airlines have to cope with much more bad weather and congestion and European airlines with not only congestion but traffic controller strikes.

Could there be another reason for being right at the top? Rescheduling? 

Life worth living again!?

Distraught Father Assassinates Controller (Lake Constance, 2002)

Only one pilot obeyed the collision avoidance system



Kaloev, the father who killed Nielsen, the controller, was released after two years for good conduct and on mental grounds, to return home and treated as a hero for meting out justice that supposedly had not been done. Indeed, in 2016, he was awarded the highest regional medal by the local Ossetian government, the medal “To the Glory of Ossetia.”

We must remember many children in that community lost their lives on that holiday trip.

Kaloev was bitter because Nielsen whom he assumed responsible was allowed to return to work with no criminal charges at all, though we stand by our account here showing the controller did his best in exceptionally difficult circumstances. In fact, in a way he caused the disaster in trying to prevent it, and the problem was the pilot of one aircraft obeying him and not the TCAS. Had Nielsen not tried, there would as we have said been no collision.

Perhaps there is some consolation for Kaloev, in that now, aged 62 he has married a woman 22 years younger who in late December 2018 gave birth to a twin boy and girl, with him saying,

“Life has turned out so that I have children once more. And I have meaning in my life again. Doctors say that everything is fine with the babies… They were born healthy, everything is fine.”

A systems and managerial tragedy that marked a community; but almost unbelievably life goes on.

A 2017 movie, Aftermath, with Arnold Schwarzenegger is very loosely based on Kaloev.


See Extract

If AF447 had had 737 MAX’s MCAS


Recently there was a fascinating piece by Bjorn Fehrm on LEEHAM News and Comment explaining why Boeing had installed an automatic trim system (MCAS) on the 737 MAX to intervene aggressively should the aircraft be in danger of stalling even with the autopilot disconnected.

The reason for this was that though the 737 as originally designed was naturally stable it sat very low on the ground to facilitate loading at airports with then limited facilities. The bottom of the engine nacelles had to flattened to allow this. However, in order to install the much more efficient larger diameter engines for the 737 MAX, they had to be moved forward. As explained by Fehrm, this was fine at normal angles of attack, but should the angle of attack become too steep the nacelles themselves would produce lift far forward of the centre of gravity, which might result in a disastrous stall with the nose being pushed up further and further. To preclude this, Boeing installed MCAS, the Maneuvering Characteristics Automation System to force the nose down.

Unfortunately, in the Lion Air crash, the pilots did not know that unlike in the previous version of the 737 the forced down trim could not be removed by pulling back on the control yoke–the STAB TRIM CUTOUT switches have to be set to CUTOUT, which is what the pilots did when the same thing happened on an earlier flight of that aircraft.

Interestingly, in another post we cited the case of the XL Airways/Air New Zealand acceptance test flight, that crashed because the pilot could not overcome the upward maximum pitch trim and upward leverage of the low-slung engines causing the aircraft to stall will insufficient height to recover. In that case, two-out-of-three of the angle of attack sensors had frozen at the same angle and the computer dismissed the odd man out. In the Lion Air crash it seems the MCAS was triggered by just one angle of attack sensor showing too steep an angle, which was quite reasonable because the high pitch indicated by one might have been genuine and it was a precautionary measure, and better safe than sorry. If the pilot had been aware of what he should do, or thought of it like the pilot on a previous flight on that aircraft, there was no reason for it to crash.

It is a pity Air France Flight AF447 that crashed into the South Atlantic did not have something like MCAS both stopping the pilot stalling the Airbus A330, and preventing him from impeding recovery by pulling back continually on his sidestick when on full manual control with no protections other than yaw-damping.



Comparing Lion Air 737 MAX Crash in Indonesia and Fatal XL Airways/Air NZ Acceptance Flight #LionAircrash

Like the Lion Air 737 MAX crash in Indonesia, the crash of an A320 acceptance test flight in France in 2008 involved the extreme trim of the horizontal stabilizer that the pilots could not overcome. See Chapter 18: Not All Pilots can carry out Test Flights.

The A320 pilots attempted to check the automatic stall protection system at too low an altitude with little height to recover should something go wrong.

Unfortunately, the angle of attack sensors due to ingress of water used to clean the fuselage had frozen in the level-flight position making the computer believe the aircraft was not going to stall.
When it eventually did stall, the extreme upward trim of of the horizontal stabilizer made it impossible to push the nose down to regain speed, for with the low-slung engines at full thrust also pushing the nose up, 
the elevators could not overcome the two. The stalled aircraft (not filled with fare-paying passengers) plunged into the sea. 

In the Lion Air case, the downward trim came about because a new safety system (which no pilots had been told about) pushed the nose down because of a faulty angle of attack sensor indicated that the aircraft was was nose-up and in danger of stalling.

WHAT THE TWO ACCIDENTS HAVE IN COMMON is failure of the pilots to deal with the extreme trim of the horizontal stabilizer and therefore being unable to recover.  

In the A320 case, there was a warning to USE MANUAL TRIM, which the pilots either did not notice or ignored–they anyway had little time.

In the 737 case, it was not so simple as the computer overrode the trim system even in manual, and the trim had to be completely disabled. The pilots did not even know that they should do that, though on when problems had occurred with that very aircraft on a previous flight the pilots had managed to do so and recovered. Unfortunately, the the pilots of the crashed flight were not told about that how those pilots had disabled the trim.

We highly recommend the reader click HERE to see the fascinating article by Bjorn Fehrm on Leeham News explaining why Boeing introduced their new anti-stall system on the 737 MAX to cope with the forward positioning of the larger engine nacelles covering the higher bypass LEAP-1B engines–the 737 conceived many years ago was designed to be very low on the ground, hence the odd (not round) shaped nacelles. 

For reference
Boeing’s just issued warning to users of the 737 MAX that was not in any of the manuals.

“This bulletin directs flight crews to existing procedures to address this condition. In the event of erroneous Angle of Attack (AOA) data, the pitch trim system can trim the stabilizer nose down in increments lasting up to 10 seconds. The nose down stabilizer trim movement can be stopped and reversed with the use of the electric stabilizer trim switches but may restart 5 seconds after the electric stabilizer trim switches are released. Repetitive cycles of uncommanded nose down stabilizer continue to occur unless the stabilizer trim system is deactivated through use of both STAB TRIM CUTOUT switches in accordance with the existing procedures in the Runaway Stabilizer NNC. It is possible for the stabilizer to reach the nose down limit unless the system inputs are counteracted completely by pilot trim inputs and both STAB TRIM CUTOUT switches are moved to CUTOUT.

Additionally, pilots are reminded that an erroneous AOA can cause some or all of the following indications and effects:

– Continuous or intermittent stick shaker on the affected side only.
– Minimum speed bar (red and black) on the affected side only.
– Increasing nose down control forces.
– Inability to engage autopilot.
– Automatic disengagement of autopilot.
– AOA DISAGREE alert (if the AOA indicator option is installed)

In the event an uncommanded nose down stabilizer trim is experienced on the 737 – 8 / – 9, in conjunction with one or more of the above indications or effects, do the Runaway Stabilizer NNC ensuring that the STAB TRIM CUTOUT switches are set to CUTOUT and stay in the CUTOUT position for the remainder of the flight.”

United Airlines “Fuel Emergency” 787 Landing at Sydney

Unlike the Avianca crash at New York in 1990, the United Airlines flight declaring a FUEL EMERGENCY on landing at Sydney seemed to have had fuel for another attempt, if not two attempts, to land should they have had to go around. They were no doubt following the airline rules to the letter and should be congratulated.Declaring a fuel emergency ensured air traffic control would do all possible to avoid them having to go around, say because of another aircraft staying longer than expected on the runway.Had they had to go around, something else might have occurred, delaying a landing, with the fuel safety margin getting tighter.

They extract below from our piece on the Avianca incident shows what can happen, though in that the copilot did not declare it was an absolute emergency as it was their last chance to land.


Avianca 52 Copilot Failed to Say “Emergency” (New York, 1990)

The survivors and relatives of those who died when Avianca Flight 52 ran out of fuel while attempting to land at New York’s JFK airport were incensed when reminded the official inquiry attributed the accident almost entirely to the first officer’s failure to use the term “emergency” in his radio transmissions to air traffic control.

Avianca Flight 52, January 25, 1990

The lights in the passenger cabin of the Colombian Avianca Boeing 707 flickered as the fuel supply to the engines became erratic. With so little fuel left, no measure could save them other than coming down on a runway or flat, open space. However, JFK airport was fifteen miles away, and the hilly ground of the affluent residential district of Cove Neck, on Long Island, lay ahead.

A few seconds later the engines fell silent, leaving only the rustle of the wind against the fuselage, soon to be drowned out by the screams and exclamations of the passengers realizing they might be facing their maker.

How, in what one would imagine to be one of the most sophisticated air traffic control (ATC) zones in the world, could the pilots and passengers of Avianca Flight 52 find themselves in such a predicament? It was due to what, with hindsight, was a whole series of missed opportunities to avoid disaster.

The first of these was not diverting to their alternate, Boston, when, on approaching the New York control zone an hour and a half earlier, controllers informed them their wait in the holding pattern would be at least forty-five minutes. The pilots possibly thought the controller was being careful and that the wait would not be very much longer. In fact, they had to hold for seventy-seven minutes.

Then, as the aircraft was subsequently handed over from one controller to another, the first officer, who was handling radio communications, used phrases such as “We’re running out of fuel.”

He evidently thought this clearly indicated their fuel predicament, but he failed to convey the true situation to the controllers, who had perhaps fifty aircraft in the sky, all in a sense running out of fuel and all wanting priority. If they started to let aircraft that had not declared an emergency jump the queue, a traffic jam would develop over the airport, perhaps compromising the safety of other aircraft also low on fuel.

Another factor explaining the controllers’ apparent lack of probing into Avianca 52’s status was that, with the aircraft being handed over successively from controller to controller, none had the time to build up a detailed picture. Aircraft have to be pigeonholed in the controller’s mind, and this is particularly so at busy times; for them it is either a normal flight or declared emergency.

When after seventy-seven minutes Flight 52 was allowed to exit the holding pattern (after the crew were asked how much longer they could hold), it was passed on to the approach controller, who, unaware of their predicament, greeted them as follows:

21:03:11 Approach:
Avianca zero five two heavy, New York Approach, good evening. Fly heading zero six zero.

After acknowledging this, the Avianca flight crew, consisting of the captain, first officer, and flight engineer, agreed on the need, when less than a thousand pounds of fuel remains in any tank, to avoid doing anything, such as raise the nose too much or accelerate violently, that might cause it to slosh to one side, leaving the outlet uncovered.

The tower controller, who was about to hand over to a colleague at the end of his shift, simply handed them over to the approach controller.

The captain told the first officer to tell approach they didn’t have fuel, but the first officer, after automatically acknowledging the order to climb and maintain three thousand feet, reverted to saying, “We are running out of fuel, sir.” The controller replied “Okay” and gave them a new heading.

Again, the captain asked the first officer if he had advised ATC they didn’t have fuel. He confirmed that he had, adding optimistically, “And he’s going to get us back.”

The approach controller then gave instructions to two other aircraft. After giving Avianca 52 a new heading, he showed his concern as one can see from the following exchange.

21:26:35 Approach control:
Avianca zero five two heavy, ah, I’m going to bring you fifteen miles northeast and then bring you back onto the approach. Is that fine with you and your fuel?

21:26:43 First officer:
I guess so. Tha [sic] you very much.

The captain asked what the controller said, but before the first officer could tell him, the flight engineer bizarrely said,

“The guy is angry.”

End of extract.

Click HERE for Table of Contents

AF447 Documentary on More4 TV

 The More4 TV documentary was good as far as it went but did not include contributory factors such as the captain only having had an hour’s sleep the night before, the poor relationship between the two copilots, and the fact that the captain was probably not in his bunk.

These and others are detailed in our account.

Click HERE for Table of Contents