[Rockin Robbins]

Well, everybody woke up this morning to stories in BBC, Wall Street Journal and all over saying that the Ethiopian pilots "repeatedly did what the manual told them to do" and were crashed by the evil plane. And, as usual, the news media, having abdicated their responsibility to apply understanding to sometimes technical reports and find the truth, are merely selling paper and electrons by inappropriate use of laziness, fishing for controversy and finding it whether it exists or not, or just plain deception. Nowhere in these stories is the Ethiopian Preliminary Accident Report quoted or summarized point by point.

To get that critical information, and why the plane really crashed, you have to watch this video by blancolirio.

Mentor Pilot will undoubtedly follow with further clarification. The long and short of it is that the Ethiopian pilot made several fatal mistakes, after his low-time (less than 100 hours in type) co-pilot did the right thing and saved the airplane by engaging the trim cutout switches to shut down the MCAS system.

The plane dived for the first time, the pilot compensated with back pressure on the yoke while the copilot recommended that the trim cutout switches should be disengaged to keep the MCAS system from applying any more down trim. The pilot agreed and they disengaged the MCAS system and automatic trim controls. From that point on, MCAS had no influence on how the plane flew.

Because the plane had throttle settings for climb and was now flying level, airspeed very quickly increased beyond the Vmo (maximum operating speed) of the aircraft. This is when flight loads on the control surfaces make it very difficult or impossible to control the plane, even difficult or impossible to manually use the trim wheels with cranks on them that I showed you in a previous post. Cutting throttles was plainly indicated to reduce loads on the control surfaces and allow the pilot to regain trim and elevator control. Yet the throttles were never touched until impact and airspeed continued to increase (duh!) to over 500 knots. That's fatal mistake #1.

(I made my own fatal mistake #1 a couple of posts ago when discussing what Skybird called the "blowback" theory, where aerodynamic loads make control surfaces impossible to input. I said at that time that Vne (Velocity never exceed) speed was that threshold. Vne is the speed where things like wings, enpennage, cabin skin and other things are torn off the aircraft, you have actually structural failure due to aerodynamic loads. It's Vmo (Velocity maximum operating) where loads on control surfaces make the plane difficult or impossible to fly.)

Fatal mistake #2 was when the pilot and copilot together were unable to move the manual trim wheels (they were overstressed by the grossly inappropriate airspeed), they attempted to use the electrical trim switches on the yoke. With the trim cutout switches engaged, these switches were not operative. Their response was to make fatal mistake #3.

They turned MCAS back on by reengaging the trim cutout switches, MCAS trimmed the plane full down and killed them all. This action was against all training, all manuals, all simulator experience. It was the exact opposite of what should have been done.

The proper thing to do was to maintain level trim with yoke pressure, then reduce throttle to get the plane down to about 300 knots, at which point, considering the low altitude, back pressure and if necessary gently apply more throttle (to maintain proper climb speed) to establish a steady climb to a safe level. THEN and ONLY THEN, they should have stabilized attitude at level flight at cruise speed and manually trimming the aircraft would have been easily done.

But what does the so-called "news media" have to say today? The pilots followed every guideline and the MCAS system, which they turned off, repeatedly turned itself back on to crash the airplane. Completely, totally, indefensibly, irresponsibly, incompetently false. The pilot crashed the plane. End of story.

Can MCAS be improved? Heck yes. Both angle of attack sensors should be hooked to MCAS. MCAS should compare those sensors to each other and to the attitude indicator the autopilot uses to trim the airplane. It should turn off malfunctioning sensors as necessary and give the pilot an alarm to reflect what was done.

The MCAS system needs to be throttled back so that at all times pilot input overrules the MCAS system. At no time should the pilot simply lack the strength to overcome the down trim initiated by MCAS. (Well, at any speed below Vmo, anyway) It probably wouldn't be a bad idea that if the pilot exerts more than X pressure on the yoke, MCAS would be cut out automatically.

But no changes can prevent a pilot from killing everybody by turning a known malfunctioning MCAS system back on with a plane already completely out of his control, flying outside the design flight envelope of the plane. It's as if a terrorist hijacker took control, tried to crash the plane, the pilot and copilot overpowered him and promptly voluntarily let the terrorist fly crash again.

Okay so the immediate cause of the crash would be the terrorist. But the actual cause would be that the pilot put the terrorist back at the controls. That is the cause of the Ethiopian Airlines crash. Pilot error.