pangolin

When are you most likely to be hand flying? Close to the ground on departure and arrival. Kind of a bad time to have the yoke yanked out if your hands.

MySaabStory

I would normally agree with you.

But ever since our president started with that b.s. I’ll have to agree that we need to source someone’s “facts” otherwise it’s b.s. like 99% of the b.s. coming out of that office.

PlaneS

The Emergency AD released for the MAX sheds some light on the system and what MAX pilots can expect if MCAS malfunctions. Some of the highlights include:

• If the autopilot is on or the flaps are extended, MCAS will not act on faulty AOA data.
• MCAS is limited to trim in 10 second increments, at 2.5 degrees max per increment, at a rate of 0.27 degrees per second. This is not a sudden nose-dive into the earth, but rather a gentle and slow buildup of nose-down trim.
• If stab trim is used to stop malfunctioning MCAS, it will restart 5 seconds after the trim switches are activated.
• The only 100% effective way to disengage the system is to move both STAB TRIM switches to CUTOUT and leave them there for the rest of the flight.
• IAS DISAGREE, ALT DISAGREE, AOA DISAGREE and FEEL DIFF PRESS are all potential alerts that may be associated with erroneous AOA data.

pangolin

Again we don’t know the cause of this tragic accident. MCAS is not inherently bad. However, coupled with erroneous airspeed indications I think it can overload the crew.

Singlecoil

I know that’s what the checklist says, but from a systems standpoint I think you would only need to turn off the switch for the autopilot trim. Then you could still use the trim switches on the yoke and not have to deal with the crank handles.

JohnBurke

Alternate facts and lies are officially permitted under the current administration.

It's acceptable to remove data which contradicts those lies, and even convene panels of biased "scientists" after sacking the experts, to try to disprove existing fact.

It is acceptable, under the current administration to change the story to a new lie on a daily basis.

Alternate facts. Everywhere you want to be. No supporting evidence required. Anything which disagrees shall be deemed "fake news."

PlaneS

You're technically right, but there's strong indicators pointing to MCAS at this point. China and other countries have taken the stance of "why take the risk?" until more is learned, which is a position I can completely understand. When two brand new transport category airplanes of the (normally extremely safe) same exact type crash just months apart under strikingly similar flight conditions, it's ok to get suspicious.

If two kids disappeared 5 months apart while walking by the house at the end of your street, would you wait for the police report to stop letting your kids take the same route home from school?

Flyfish49

This ^^^^^^
Thank you, PlaneS.

JohnBurke

These weren't kids. They were aircraft. Opposite sides of the world. Different continents. Not at the end of the same street. Different companies.

The only two commonalities presently known are three: both were the same type aircraft; both involved a crash, and both are under investigation with the common link that we don't know what happened in either case.

If two prius crashed somewhere in the world, would you refuse to drive a prius? If two people choked on a hamburger somewhere in the world, would you refuse to eat a humburger? If two people on two different airlines on two different continents got sick from the same brand of inflight food, would you refuse to eat again? Straw and irrelevant, all, much like the mythical kid on the street, though that example is worst of all, as it implies and assumes too much of the irrelevant.

Many moons ago I had a job interview for a Cessna 207 in which the owner sat in the right seat and directed the trim run full nose up. Take off, fly a left pattern at 200, and land. Run trim full nose down. Takeoff, fly a right pattern at 200' and land. It's not the way I would conduct a screening flight, but I've seen weirder and worse. His view was that many pilots wouldn't think to keep the airplane slow and manageable, and wouldn't focus on flying the airplane; he could tell from the pilot's reaction and behavior, quite a bit about the makeup of that pilot.

While I don't advocate that practice, there are those who seem to feel that automation is there to fly the airplane for them, to do the dirty work of actually manipulating controls, and who all but advocate decision making to alerts, displays, annunciators, messages, etc. A trim which moves at a third of a degree/second isn't really an imminent threat unless one isn't flying the airplane. If one takes off, goes to automation, and waits until it runs far enough to disconnect the autopilot with a full deflection, then accelerates, the problem may become harder to handle than it needs to be; it's not like the warning signs aren't there, if one is flying the airplane and staying situationally aware. Even with automation engaged.

Presently we don't know what happened. Speculation is neither professional nor warranted. An investigation is underway. The FDR is in hand. It's prudent to wait to see what is revealed.

pangolin

So how many of you 737 drivers have practiced erroneous airspeed indications along with simultaneous trim runaway while hand flying in the sim?