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Old 03-15-2019, 01:19 PM   #81
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Yea, the slow spool up on the 727 did cause a few really bad landings. I wasn't a huge fan of that plane, ya never knew if it would give you a good or bad landing.
Talking about this to an older fighter pilot who was there in the very early days. He said one plane, F-100?, I think, once you turned final it was just a question of how hard you going to hit the ground. Too late to go-around after you turn final. Probably flame-out if you tried. They crashed near a thousand or so.


Come a long way. Take off and land on autopilot and blame someone else if it doesn't work every time.
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Old 03-15-2019, 04:10 PM   #82
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Your understanding is pretty good and nicely expressed in layman's terms.


Any pilot input, either yoke movement or trim input overrides the MCAS for 5 seconds. The autopilot has its own trim circuitry, and if the autopilot is on, MCAS is disabled.


The "nudge down" feature is new, but the idea of protecting the aircraft against stalling is as old as jets. In all jet aircraft there is a "stick-shaker" which behaves as the name suggests if the aircraft approaches an aerodynamic stall. In many, if the "shaker" is ignored, a "stick-pusher" takes over.

Thanks, and on the MAX, would the stick shake when the "nudge down" feature activates? Or does it nudge down silently? Sounds like it's silent from what I've read, or what's implied by what I've read.
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Old 03-15-2019, 05:03 PM   #83
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Bloomberg is reporting that at the Ethiopian site they have found the stabilator jackscrew trimmed full nose-down.
That would explain the porpoising described by land observers. High rate of speed as the pilots tried to correct nose down and loss of altitude with power, fighting mal adjusted nose down trim. The FDR will tell the tale.
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Old 03-15-2019, 05:44 PM   #84
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That would explain the porpoising described by land observers. High rate of speed as the pilots tried to correct nose down and loss of altitude with power, fighting mal adjusted nose down trim. The FDR will tell the tale.

An adjustment to my post. I think it is a pitch trim jackscrew, and not the actual stabilator.


Makes it easier to understand the sudden change of heart on the part of FAA. May suspect an MCAS fault somehow differs from the customary pitch trim runaway.
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Old 03-15-2019, 05:50 PM   #85
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Thanks, and on the MAX, would the stick shake when the "nudge down" feature activates? Or does it nudge down silently? Sounds like it's silent from what I've read, or what's implied by what I've read.



I don't know the airplane well enough to say, and the real question for me is: does it move the yokes when it intervenes. Boeing design philosophy generally requires controls which are being operated by automation move as though the invisible hand is flying the airplane.


BTW, I may not have been clear, there is nothing subtle about the "stick-shaker". It will not allow you to overlook it.
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Old 03-15-2019, 05:55 PM   #86
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Talking about this to an older fighter pilot who was there in the very early days. He said one plane, F-100?, I think, once you turned final it was just a question of how hard you going to hit the ground.
There's an excellent read on the perils of flying the F-100 titled, very tellingly:

"Bury us Upside Down"

It is primarily about using the F-100 as a stop-gap fast FAC (forward air controller) in the early part of the Viet Nam war, since the slower observation planes normally used in the role could not survive in the battle space. It involves a lot of discussion about the perils of that plane, regardless of combat.
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Old 03-15-2019, 06:30 PM   #87
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I don't know the airplane well enough to say, and the real question for me is: does it move the yokes when it intervenes. Boeing design philosophy generally requires controls which are being operated by automation move as though the invisible hand is flying the airplane.


BTW, I may not have been clear, there is nothing subtle about the "stick-shaker". It will not allow you to overlook it.

Got it. I like the approach of the stick reflecting any automated controls so you know exactly what it's doing, or trying to do.
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Old 03-15-2019, 07:43 PM   #88
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All complete horsecrap.


Back in the day, many pilots didn't have manuals, checklists, even had to have the ground crew start the aircraft.


Sure, back in the days of many accidents....but the reality was the good pilots survived longer.


Many pilots should never be pilots.


Heck, any pilots here ever tow a boat with a helicopter?


Probably few, but a pilot can figure out how to make an aircraft perform when it is not supposed to. Even if it means shutting off every dang system. And some have proved the impossible even in modern aircraft.


Like driving boats, some shouldn't, some can no matter what.

Paul,

Not sure what you're calling complete crap, and not sure how far you're going back when pilots didn't have manuals, checklists, etc.....

But I started flying in 1968 privately and commercially in 1981 and I always had the above in any plane or operation.

Towing a boat with a copter would be interesting.... never been in one, they scare the bejesus out of me.

True some pilots should never be pilots and some some folks should never be boat operators.
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Old 03-16-2019, 01:23 AM   #89
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On the 737 (or any plane with underslung engines) there is a tendency for the nose to pitch up when power is applied and drop when power is reduced. This is countered by elevator and/or stabilizer forces. The control authority is dependent on speed. Higher speeds allow the elevator/stabilizer to generate more force per unit of deflection. Slow speeds reduce authority. In cases where the airplane is going relatively slowly and a lot of power is applied the nose up pitching moment could be quite high. If the aircraft is already slow, a pitch up in this condition could lead to a stall. Because the Max has higher thrust engines than the previous model 737, the MCAS system is designed to help control the nose up pitching by applying nose down trim in order to make the Max handle more like the 737NG. This allowed Boeing to claim that the handling of the NG and Max are the same and thus either one can be flown under the same pilot type rating.

In the 737 the stabilizer trim can be operated by the either pilot via switches on the control wheel. The autoflight system can also operate the trim. Usually only one operator (pilots or autoflight) can operate the trim system at a time, although it seems that the MCAS will only operate the trim if the autoflight is off. In each case the trim has two speeds (fast and slow) and the speed is dependent whether the flaps are up or not. High speed is for when the flaps are not fully up. The trim can be operated manually by turning the hand wheel. The speed of the operation in that case is determined by how fast the wheel is turned.

Because of the way the system is set up, any movement of the stabilizer trim will cause the trim wheel to move. In normal flight operations this wheel is often moving. If the MCAS moves the trim, the wheel will turn.

As has been mentioned, if the plane is being operated normally and there are no MCAS system malfunctions, the pilots should never experience MCAS operation of the trim.

If the aircraft is trimmed, the control column will be in the neutral position. Only when the elevator is deflected will the column move. Changing the trim does not cause the column to move. Normally the trim is used to hold the pitch attitude with the elevator at neutral. The normal method of flying large aircraft is to change the pitch with the elevator and then use the trim to hold it in the desired attitude. As the trim is set the elevator will come back to neutral.

A couple of things that have not been mentioned in the reporting that may have something to due with this incident.

- If the autothrottles are on and the plane is experiencing large deviations in speed, the autothrottles will be applying and removing power trying to get the plane to the set speed. Because of the pitching moment due to thrust, this can exacerbate any pitch control issues. We don't know if the autothrottles were on during this event, but normal takeoff procedure would be to have them engaged.

- If the trim was not set properly before takeoff (it has happened) the aircraft could be difficult to lift off or lift prematurely. In either case the force on the control column would be something that the pilot does not expect and could lead to an upset because of the reasons mentioned above.

- One of the things mentioned is that the aircraft was traveling at high speed at the end. With the trim full nose down (according to the jackscrew) the crew may not have the physical strength to pull the nose up or to hold it up for any length of time (even with both pilots pulling with both feet on the panel).

- The emergency checklist has a drill for trim runway. However, the first thing on the page is that the drill applies if the trim is "Uncommanded stabilizer trim movement occurs continuously." The MCAS does not operate the trim continuously, it does it intermittently. This is a subtle difference, but might cause less experienced pilots to think that this drill is not applicable to operation of the trim due to a MCAS fault. The pilots should be trained to use the runway trim drill any time the trim is not working as they expect.
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Old 03-16-2019, 05:32 AM   #90
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"Yea, the slow spool up on the 727 did cause a few really bad landings. I wasn't a huge fan of that plane, ya never knew if it would give you a good or bad landing."

All the jet engines of that era had a slow spool up time from flight idle..

The 727 gear were behind the center of rotation , so is someone attempted to flair the plane, as they would for other aircraft to slow the rate of descent, it simply banged the gear harder on to the runway.

Smooth 727 landings were a learned skill, not a matter of luck.
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Old 03-16-2019, 06:17 AM   #91
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"Yea, the slow spool up on the 727 did cause a few really bad landings. I wasn't a huge fan of that plane, ya never knew if it would give you a good or bad landing."

All the jet engines of that era had a slow spool up time from flight idle..

The 727 gear were behind the center of rotation , so is someone attempted to flair the plane, as they would for other aircraft to slow the rate of descent, it simply banged the gear harder on to the runway.

Smooth 727 landings were a learned skill, not a matter of luck.
FF,

I could argue landing that plane did contain a bit of luck. It was very hard to predict exactly when the gear would touch down and the slightest imperfection in landing technique (or outside forces, wind/gust) would make a hard landing. I only had about 2500 hours in that plane, some as an engineer, and while I could do pretty well on landings, occasionally one would bite me. And not much different than the guys with 10,000 hours in that plane. The other Boeings were significantly easier to land.
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Old 03-16-2019, 06:19 AM   #92
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ssobol,

Really good review of the aircraft.
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Old 03-16-2019, 06:35 AM   #93
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Poor flying skills may be the big problem , even with well trained US pilots.

The FAA requires 2 hours of "off" time for every flight hour, over 8 hours.

The companies have discovered its cheaper to install a couple of extra pilots on long over water flights' so seat hopping every crew member can stay under 8 hours , OK to sleep fast and turnaround.

The hassle is with 3 or 4 pilots and only 2 landings , one going out, one on arrival at home landings must be logged to have each crew member be FAA current.

Add this to the companies desire to have the AP fly as it is fuel cheaper and lots of folks warm a seat for thousands of hours but do not increase their skill set.

Therefore the desire to automate as much as can be done.

This is seldom a hassle for junior folks that may do 5-7 legs a day .
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Old 03-16-2019, 06:56 PM   #94
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... The 727 gear were behind the center of rotation ....
For tricycle gear airplanes (i.e. most of them), when the plane is on the ground the center of rotation is the main gear. When in the air, it is the center of gravity. If the plane is on the ground and the center of gravity moves behind the main gear, the plane will sit on its tail. For takeoffs and landings you want the CG to be a bit in front of the gear rotation point. The farther forward the CG is from the gear, the harder it is to get the plane to rotate for takeoff. You pretty much design the airplane so that the CG is always in front of the gear when the plane is operating (there are a few exceptions, but they only occur when the plane is in flight).

Occasionally aircraft that are being loaded have tilted back onto their tails because of too much stuff being in the back before the stuff in the front was loaded. Usually this is countered by a strut the ground crew puts under the tail. Some operators tie the nose gear to the ground during loading (e.g. FedEx).

As planes get longer the risk of a tail sit is greater. Nowadays you will see that the ground crew puts struts under the tails of Boeing 737-900s because there is a risk that as passenger leave the plane (front passengers first) and the front baggage hold is emptied, all the people still in the back could cause a problem.
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Old 03-18-2019, 08:17 AM   #95
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Poor flying skills may be the big problem , even with well trained US pilots.

The FAA requires 2 hours of "off" time for every flight hour, over 8 hours.

The companies have discovered its cheaper to install a couple of extra pilots on long over water flights' so seat hopping every crew member can stay under 8 hours , OK to sleep fast and turnaround.

There is not other option for long flights, ya can't just beam another crew up there.....

The hassle is with 3 or 4 pilots and only 2 landings , one going out, one on arrival at home landings must be logged to have each crew member be FAA current.

That's true, but that's what recurrent landings are for. I did that as a senior FO on the 747 where I got a ton of time off, but did do the recurrent on a regular basis.

Add this to the companies desire to have the AP fly as it is fuel cheaper and lots of folks warm a seat for thousands of hours but do not increase their skill set.

Therefore the desire to automate as much as can be done.

Personally, I feel the autopilot thing is over emphasized. I could argue to turn it off for a big part of the departure or approach/landing phase. It's just more fun. But nothing wrong with it when required or things get really busy. We did have a few guy that did a little as possible and hated the job, and wonder if they could really fly when the chips were down. I suggested they get a job at Walmart.... without success.

This is seldom a hassle for junior folks that may do 5-7 legs a day .
As to the MAX, I don't believe that seniority is a big issue with the skill of the pilots. It's not a really long range plane so the pilot's should get plenty of landings to stay current. And landings really isn't the issue with the Max issue. It's a lack of training or information or procedures (or all of the above) in dealing with a Max failure.
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Old 03-18-2019, 12:41 PM   #96
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There is not other option for long flights, ya can't just beam another crew up there.....

The old way , 25+ hour layovers is legal, but sucks!
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Old 03-18-2019, 12:58 PM   #97
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If you go here to this pilots channel he explains the mcas and what could happen with it.

Mentour Pilot youtube channel

Look for Boeing 737 Stall Escape manoeuvre, why MAX needs MCAS!! video



should be one of the more recent ones. Right at the top.


Really good explanation of the mcas and what can happen.
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Old 03-18-2019, 01:42 PM   #98
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From: Capt. Jack M. Schmidt, Ret.
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No less than five people have called me to say, "Hey dude I'm booked on a MAX-8 to go to Timbuktu soon, what do I do? My answer...better get your affairs in order and, oh, by the way...that life insurance policy of yours...make sure it's paid up…and my full name is "Jack M. Schmidt, Jr." make sure you get the Jr. in there. If the money goes to my dad's estate my brother would get half...don't want that to happen now, do we?

Seriously, the short version is (ah s--t there ain’t no short version) in the fifties, sixties and seventies two-bit third world countries were starting up their own national airlines and they wanted their own citizens to fly the airplanes. But most couldn't ride a freaking camel, let alone fly an airplane, so at first the Americans, Brits, Aussies, Kiwis and a few Irishmen got these jobs. When I worked for Northwest we sold airplanes to Onassis (Olympic Airlines) in Greece (maybe 2nd world) and the Union of Burma Airline. We opened pilot bases in Athens and Rangoon. (I bid them both but the bids went senior so I got Honolulu.) The company staffed them with NW pilots to train the locals how to fly the Boeing 720 and 727.

Hell, the CEO at Emirates today, the world’s premier airline, is an Englishman.

Fast forward to the eighties, along comes Airbus with cockpit automation to die for (literally) which make it "almost" impossible to f--k...er screw up and crash the airplane. The French actually said "impossible" (yeah right). Even though their prototype A-320 crashed at the Paris Air Show in 1988, the “Bus” smoked Boeing's 737 in sales efforts (no pun intended). The 737 is still being cranked out on a Type Certificate that was issued by the FAA in 1967 even though today's versions bear no resemblance to the 1967 version. Especially on the MAX-8/9 series on which the wings, engines and cockpit automation have all been "upgraded."

Here is how s--t happens. My information is this: Boeing, on the MAX, moved the engines forward, but looking at the pictures, it appears to me that they may have moved the entire wing, engines and all, forward. This moves the CG forward along with the Mean Aerodynamic Cord which affects trim (tech talk but could be a bad thing). You do this because you think the computers that are flying the airplane most of the time can more easily recover from a stall with a forward CG. (I guess crashing is one way to recover from a stall but it’s never been my favorite.) Next you realize there might be a problem with a nose-heavy airplane (duh!) so you design software to counter act but you only give the computers that are flying the airplane access to one channel of data from the pitot-static and/or the air data computers which may deliver faulty or corrupted data. (Even though most every modern airplane has three complete and independent systems, the MAX only has two.) Next the guys you sold this turkey to put one (if not both) inexperienced and poorly trained pilots in the cockpit. Air France did this with a different model of the Airbus and they put it into the Atlantic off Brazil.

This is a disgusting exercise in technology for technologies sake (and to sell airplanes) that didn't work out, designed by aeronautical and software engineers just out of school who are supervised by 28-year old “senior” engineers, none of whom have a freaking clue how to fly an airplane. Ask my son, he went through this at General Atomics Aeronautical Systems on the Predator. Then you make sure the only real pilots you expose this fraud to are your in-house test pilots who like their jobs and wouldn't say
s--t if they had a mouth full.

Previously it was “If’n it ain’t Boeing, I ain’t going” now changed to “If it is Boeing, I ain’t going”

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Old 03-18-2019, 02:31 PM   #99
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FAA's mission statement to "promote aviation" was removed from their charter in 1996 by an act of Congress.
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Old 03-18-2019, 02:58 PM   #100
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True, but the FAA's mission and mandate for air safety was not. And at this they have failed consistently, like all government bureaucracies.
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