Good ol' CNN fake news

[Rockin Robbins]

Clickbait titles are mostly annoying. But simply getting the story wrong to shoehorn an important event into a political class struggle narrative is both repugnant and dangerous. A perfect example is the present Boeing 737 Max brouhaha.

Quoting Ethiopian Airlines, not the Preliminary Accident Report, news all over the world is screaming the pilot "repeatedly followed Boeing instructions" and the evil MCAS system on the 737 Max couldn't be turned off. It, like Christine the killer automobile in the movies, wrested control from the pilot and killed the crew and 150 passengers. Boeing purposely didn't care about safety at all and simply rushed a dangerous new product to the market. People need to go to jail. Boeing should be crippled.

The fact is the Preliminary Accident Report clearly states three fatal mistakes made by the pilot. The procedure to deal with a trim system failure has been the same and unaltered since the first 737 flight on April 9, 1967, and the elevator trim cutout switch, the solution to the problem has been on every single 737 of all varieties since that time.

In addition, the situation and remedy are not just in the manual, they are what is called a "memory procedure," required to be memorized by all pilots of all varieties of 737 as a prerequisite to receiving a type certificate allowing pilots to fly these beasts. Yes, there IS a test.

So what does the Preliminary Accident Report (not the highly prejudiced Ethiopian Airlines) say about the crash? I can find one place that covers that, the You Tube channel of professional passenger pilot Juan Brown on his blancolirio channel.



He also links to the report itself http://www.ecaa.gov.et/documents/204...2C(ET-AVJ).pdf and information on the trim system https://www.satcom.guru/2019/04/stab...and-range.html so that his reporting can be contradicted or confirmed by the facts of the case, not the comments of an airline, whose motivation is to protect itself and its pilots.

The 737 Max series of jets has a system called MCAS, the Maneuvering Characteristics Augmentation System. The Max series uses larger, heavier engines than the rest of the 737 series. That makes the plane fly differently. In order to allow pilots to use the same type certificate to fly the entire series, MCAS applies nose down trim if the plane approaches stall to save the crew and passengers' cookies, but also to make the Max fly similarly to earlier 737s. MCAS is not just in the 737 and it is not a new system. It also appears and has been used with a perfect safety record in US Military KC-46 tankers. It is NOT a bandaid put in place to save an unflyable airplane.

So here's the short version of what happened. The pilots took off normally, leaving the tarmac with flaps down and power settings per that configuration. They achieved proper altitude to raise flaps, momentarily leveled off, stabilized the plane, and then applied 94% climb throttle and applied up elevator to stabilize speed at max climb angle.

That's when things went wrong. There was a problem with the left angle of attack sensor on the plane, perhaps a bird strike, but that sensor said that their angle of attack was not appropriate to the airspeed of the plane, and the MCAS system applied a couple of units of down elevator trim. The pilot responded by pulling back on the yoke, against the pressure caused by the down trim in the system by MCAS. He then used the electrical trim switch on his yoke to trim in the upward direction to neutralize control pressures.

When the plane nosed down slightly on the first MCAS control, the sensor outside the plane didn't move at all. MCAS thought the plane was still stalling. After a short delay, programmed into the system, MCAS applied more authorative down trim. The plane had been either level or slightly nose down this entire time so far since the first MCAS "adjustment."

However the pilot and copilot forgot to fly the plane. Their throttles were still set at the 94% full climb position. The plane was accelerating like a dragster and they never touched the throttles throughout the flight, all the way to impact. That's fatal mistake #1.

After MCAS provided the larger down trim in its second attempt, the co-pilot, a low time guy with less than 100 hours in type, remembered that memory procedure for a trim overrun (exactly what an MCAS malfunction causes) and recommended engaging the elevator trim cutout switch on the console of the aircraft, yes the same elevator trim cutout switch that has been on every 737 of any type built since 1967 for three generations of pilots, and the procedure for using it is required to be memorized by every pilot of the 737 series.

The captain agreed and they disengaged the automatic elevator trim system by throwing the switch. As of that moment, MCAS was disconnected from the elevator trim jack. It would continue to issue commands to the motors, but since the power to those motors was interrupted by the open elevator trim cutout switch, those commands COULD NOT BE IMPLEMENTED.

In fact, after it was disconnected, the Preliminary Accident Report clearly says that MCAS commanded many additional clicks of down elevator trim which were unable to be carried out because the elevator trim cutout switch was activated. The plane was flying level. It accelerated past the maximum operating speed of the airframe and the crew didn't touch the throttle.

They then attempted to manually trim the elevator up. That's mistake #2. First fly the plane! Proper procedure would be for both of them to ignore other problems, since they now had control of the airplane. They should have realized that they were unable to trim the elevator because their over 400 knot airspeed was putting aerodynamic loads that were too great for them to overcome manually and if they didn't get their act straight (overspeed warnings were screaming in their ears from the point they exceeded 360 knots and throughout the remainder of the flight), they would shortly have no yoke authority either.

The immediate need was to reduce airspeed. The throttle should have been retarded to level cruise setting. After the plane slowed down they STILL should have ignored the out of trim condition, and achieved a climb to a safe altitude, using the yoke alone, ignoring trim. They would adjust throttle to achieve that climb, of course.

Then, at a safe altitude, throttles set at level cruise positions, plane straight and level, being held that way by the yoke against the flight loads of the bad trim, it would have been easy for one of them to manually trim the plane to neutral. At that point management would take over. Either airline management, the tower, or the pilot would make the decision to continue to destination (a safe choice) or return to takeoff airport. But none of this happened. They simply forgot to fly the airplane! They were still in level flight at takeoff 94% throttle, accelerating to past maximum operating speed of the 737. That was fatal mistake #2

Both their efforts on the manual trim wheels were unsuccessful at moving the trim. That induced fatal mistake #3: the pilot disengaged the elevator trim cutout switch so he could use his electric trim switch on his yoke. The elevator trim obeyed his commands. After a delay of a few seconds as the software was operating properly, MCAS applied full down trim, immediately crashing the airplane. By impact, it was still at 94% power, traveling over 500 knots, an almost impossible speed for that plane to achieve at that low altitude.

It is as if a terrorist had seized control of the plane, diving it to its doom. But the pilot and copilot overpowered the terrorist, resuming control of the plane. And then they decided that perhaps the terrorist was better able to handle the situation than they, and they voluntarily put the terrorist back at the controls, allowing him to crash them.

Who crashed the plane? The proximate cause was the terrorist, but the ultimate cause was the fatal decision to put the terrorist, who they knew was intent on turning a perfectly good airplane into an ugly crater in the ground, back in control of the aircraft.

Substitute MCAS for terrorist and that's what happened. The pilot crashed the plane. In the words of Maxwell Smart, everybody is entitled to one fatal mistake. He made three. End of story.

Edit: I have just read the actual Preliminary Accident Report in its entirety and it multiplies my statements above times 2. It includes the instructions supplied by Ethiopian Airlines to its pilots. They are absolutely clear what procedures are to be followed in an MCAS induced trim overrun situation. The pilot possessed the information sufficient to save his life.

Remember: the contents of the Preliminary Accident Report itself, which you now have the opportunity to read, and which is not supplied as reference in any major media reports, is news. Everything else is propaganda, editorializing, exposure of prejudice, lack of understanding, unsupported speculation. That is what pretends to be news nowdays. The news media AS A WHOLE, regardless of political position, country of origin or status, has completely abandoned the practice of doing news.

[Platapus]

Thank you very much for taking the time to post this.

[vienna]

Originally Posted by mapuc

Isn't this what they call Clickbait ?

Markus

Yes and so is this:

Good ol' CNN fake news

<O>

[Dowly]

I know I'm going to regret this, but someone has to add a pinch of realism to this rambling.

Originally Posted by Rockin Robbins

MCAS is not just in the 737 and it is not a new system. It also appears and has been used with a perfect safety record in US Military KC-46 tankers. It is NOT a bandaid put in place to save an unflyable airplane.

KC-46 is a 767 and the need for MCAS is for different reason (changing fuel load). The KC-46 also includes various safety systems that the MAX doesn't, for example the pilot can cancel out MCAS by moving the yoke. Apples and oranges.

Moreover, while the MAX 8 MCAS will reset and come back on automatically, the KC-46’s system is “disengaged if the pilot makes a stick input,” according to the Air Force. “The KC-46 has protections that ensure pilot manual inputs have override priority.”

From: http://www.airforcemag.com/Features/...AS-System.aspx

When the plane nosed down slightly on the first MCAS control, the sensor outside the plane didn't move at all. MCAS thought the plane was still stalling. After a short delay, programmed into the system, MCAS applied more authorative down trim. The plane had been either level or slightly nose down this entire time so far since the first MCAS "adjustment."

However the pilot and copilot forgot to fly the plane. Their throttles were still set at the 94% full climb position. The plane was accelerating like a dragster and they never touched the throttles throughout the flight, all the way to impact. That's fatal mistake #1.

They were fighting the nose down at this point and were still at low altitude. Reducing throttle *might* have made the nose down worse and as they were climbing, I see no reason to not get at a safer altitude.

After MCAS provided the larger down trim in its second attempt, the co-pilot, a low time guy with less than 100 hours in type, remembered that memory procedure for a trim overrun (exactly what an MCAS malfunction causes) and recommended engaging the elevator trim cutout switch on the console of the aircraft, yes the same elevator trim cutout switch that has been on every 737 of any type built since 1967 for three generations of pilots, and the procedure for using it is required to be memorized by every pilot of the 737 series.

Earlier 737s required flipping one switch to stop autotrim, leaving the electrical trim still operational. The MAX, however, required turning off also the electrical trim leaving the crew with only manual trim. This is what they did.

With the 737NG cutout switches, MCAS runaway is stopped by just throwing the autopilot cutout switch, leaving electric trim fully operable.

With the 737MAX cutout switches, MCAS runaway is stopped by throwing both switches, losing electric trim altogether. In this case, the flight crew must rely on manual trim via turning the trim wheel/crank. As discussed above, the manual crank can bind up, making flying much more difficult.

From: https://www.satcom.guru/2019/04/stab...and-range.html

In fact, after it was disconnected, the Preliminary Accident Report clearly says that MCAS commanded many additional clicks of down elevator trim which were unable to be carried out because the elevator trim cutout switch was activated. The plane was flying level. It accelerated past the maximum operating speed of the airframe and the crew didn't touch the throttle.

It flew *somewhat* level for about 30 seconds and only because both pilots were fighting the nose down.

They then attempted to manually trim the elevator up. That's mistake #2. First fly the plane! Proper procedure would be for both of them to ignore other problems, since they now had control of the airplane. They should have realized that they were unable to trim the elevator because their over 400 knot airspeed was putting aerodynamic loads that were too great for them to overcome manually and if they didn't get their act straight (overspeed warnings were screaming in their ears from the point they exceeded 360 knots and throughout the remainder of the flight), they would shortly have no yoke authority either.

They were trying to fly the plane, both of them. Problem that requires both pilots to pull back on the controls to keep the plane from nosing down is not something they can just ignore. The plane reached 400kts when it was going down, not earlier than that. Its speed hoovered around VMO before until the final dive.

The immediate need was to reduce airspeed. The throttle should have been retarded to level cruise setting. After the plane slowed down they STILL should have ignored the out of trim condition, and achieved a climb to a safe altitude, using the yoke alone, ignoring trim. They would adjust throttle to achieve that climb, of course.

I would imagine that reducing airspeed and leveling out would make the AND condition even worse. Definitely not something that they could just ignore. Again, the both the pilots at this time are fighting the plane.

They simply forgot to fly the airplane! They were still in level flight at takeoff 94% throttle, accelerating to past maximum operating speed of the 737. That was fatal mistake #2

The plane was not in level flight. Both pilots were fighting to keep it level with varying success.

Both their efforts on the manual trim wheels were unsuccessful at moving the trim.

Indeed. A problem that would not have occurred had there been a way to disable MCAS without affecting electrical trim.

By impact, it was still at 94% power, traveling over 500 knots, an almost impossible speed for that plane to achieve at that low altitude.

Umm... yeah... the plane was in a steep -40deg dive when it reached 500kts.

It is as if a terrorist had seized control of the plane, diving it to its doom. But the pilot and copilot overpowered the terrorist, resuming control of the plane. And then they decided that perhaps the terrorist was better able to handle the situation than they, and they voluntarily put the terrorist back at the controls, allowing him to crash them.

Who crashed the plane? The proximate cause was the terrorist, but the ultimate cause was the fatal decision to put the terrorist, who they knew was intent on turning a perfectly good airplane into an ugly crater in the ground, back in control of the aircraft.

So.. the MCAS was intent on crashing the plane then? Great safety system!


Here's portion of the trace from page 26 of the report. Does that look like the had control of the plane and were at level flight?