Irony: When Safety Equipment Kills You

[Colonel]

No one seems to have noticed the irony yet, that [i]secret[/i]
safety equipment designed to avoid a stall, results in
a vertical descent killing everyone on board:

[quote]Boeing kept airlines and pilots in the dark about an automated background trim system on the 737 MAX that may be implicated in the first crash of the new model in Indonesia last month. The trim system, which is meant to improve pitch characteristics and [b]stall protection, wasn’t even described in any of the documentation provided to pilots[/b] transitioning to the new aircraft.

Lion Air JT610, a new MAX8 with only about 800 hours on the airframe, plunged into the Java Sea off Jakarta on Oct. 29, killing all 189 people aboard. Prior to the crash, the aircraft flew through repeated pitch, airspeed and vertical speed excursions before diving almost directly into the water about 12 minutes after takeoff.

According to sources at two airlines operating the MAX series, the system in question is called Maneuvering Characteristic Augmentation (MCAS) and is intended to improve pitch response at high angles of attack. It was added to the MAX models partly because the aircraft has heavier engines than the previous 737 NG models and the airplane's center of gravity is biased more forward.

MCAS is [b]activated without pilot input[/b] and would typically come alive in steep turns with high load factors, but only when the airplane is being flown manually. According to a minimal description provided to AVweb, MCAS operates only in flaps-up flight and is inhibited in any other configuration. MCAS intervenes at a threshold angle of attack and automatically trims nose down at a rate of 0.27 degrees per second to a maximum of 2.5 degrees. Stabilizer input is lower at high Mach numbers, but more aggressive at low Mach. The Wall Street Journal said Boeing [u]didn't disclose MCAS details to cockpit crews because it was worried about overwhelming them with more technical detail[/u] than needed or could digest.  Boeing also said [b]pilots were unlikely to encounter MCAS intervention[/b] during their normal flying.

Pilots trained on the MAX weren’t given even minimal briefings on MCAS, according to an interview with Jon Weaks, president of the Southwest Airlines Pilots Association published in the Seattle Times early Tuesday. “We do not like the fact that a new system was put on the aircraft and wasn’t disclosed to anyone or put in the manuals,” Weaks told the Times. And both Boeing and the FAA have warned that the system may not be performing as it's supposed to.

American Airlines, which also operates the MAX8, also provided its pilots with new documentation on MCAS hurriedly provided by Boeing after the Lion Air crash. Because MCAS relies on angle of attack data from the aircraft’s vane-type sensor, one focus of the Lion Air investigation is on the AoA sensor itself, which appears to have been replaced as faulty prior to the accident. The aircraft also reportedly had a history of unreliable airspeed indications. It's unclear if the two are related to the accident or how they affect MCAS operation. 

On the Pilots of America online forum, an American Airlines pilot posted an informational bulletin from a pilot’s association and added this: “We had NO idea that this MCAS even existed. It was not mentioned in our manuals anywhere (until today). Everyone on the 737 had to go through differences training for the MAX and it was never mentioned there either.” [/quote]

[b]Unintended consequences.[/b]  They are real.

Learn your aircraft systems!

[Colonel]

A simple example of the dangers of safety equipment:

When an aerobatic aircraft is imported into Canada, TC
insists that a fire extinguisher be installed.  This is really
dangerous, but TC doesn't care about causing accidents,
I guess.

I know of one aerobatic pilot that had a fire extinguisher
come loose in the cockpit under negative G.  Smashed him
in the face, flew up and broke the canopy.  Thanks, TC.

Another time, I was doing aerobatic instruction (in someone
else's aerobatic aircraft) and I noticed a large, heavy metal
fire extinguisher floating loose past the pilot's head in the
left seat (I was in the right seat) during zero G.

Thanks, TC!

Research the last fatal accident of the RAF Red Arrows.  You
guessed it, cause by "safety equipment".

It's too bad that no one in aviation knows what a cost/benefit
analysis is.

[Eric Janson]

From what I understand the MCAS system is not even mentioned in the 737 books.
Going to be expensive for Boeing - especially if this system contributed to the crash.

[Colonel]

People in aviation today seem to think that the fundamentals are uninteresting.

And, then people die.

At the risk of preaching to the choir:

[size=18pt][b]-> [u]LOOK OUTSIDE[/u] <-
-> [u]ATTITUDE + POWER = PERFORMANCE[/u] <-
Stick & Rudder Skills
System Knowledge[/b][/size]

The above NEVER go out of style, regardless of whatever TC/four bar/avcan brain trust might opine.

There will be [b]NO NEW CAUSES[/b] of aviation accidents in 2018.

[Colonel]

Here's a free stick & rudder lesson

[b]LET GO OF THE STICK[/b]

and unless you're Bob Hoover or Rob Holland,
the aircraft will almost certainly fly better.

I used to suggest

[b]LOWER THE NOSE[/b]

but that was too complicated.

[Chuck Ellsworth]

[quote]LET GO OF THE STICK[/quote]


And always rim for new attitude/power changes.


That will guarantee airplane will fly better hands off.

[Nark1]

I wouldn’t say I’m constantly trimming, but in the Stinson I'm on it a lot with a few bumps.
In the 180 it’s fairly constant once I get established in the phase of flight. 

In the Airbus... what’s trim?
Blackhawk... trim is the ball. Igor should have talked to fixed wing guys before making up terms. 

[Colonel]

[quote]Insler said although MCAS isn’t specifically described in United training manuals, [b]runaway trim[/b] procedures are:

“[b]You have to manually take control[/b]—that is one of the early things they teach you when you fly jets. The procedure is there in our manual, and we practice this over and over again. The first time I see an adverse event, I want to see it in a simulator, not with 300 people behind me,” Insler said in the Forbes report.

In an interview with the Seattle Times, Insler compared automated background systems on airliners to watching television. “[b]I don’t need to know [i]how[/i] it works[/b],” he said.[/quote]

Interesting.  And I hope that by the time someone sits in the left
seat of a large aircraft, they have heard about runaway trim before.