Lionair 610 crash

[Quickstatus]

That manufacturer logic surprises me. If the assumption is that all pilots are competent at all times and especially in a stressful emergency, why introduce a measure that takes away control authority from the pilot in an emergency whether real or otherwise.

The alternative is better fit in real life - that:
Not all pilots are be truly competent in an emergency so a protective automated aid is engineered.
However that logic contradicts the Boeing Bulletin which relies on a competent flight crew in an unexpected emergency,

 

[jb747]

6000, 7000hrs each. In Australia would these pilots even qualify for the FO ladder?

Whilst not a huge amount of time in the grand scheme of things, they're quite respectable numbers of hours.

But, the number of hours doesn't tell the entire story. I joined QF with just on 1,000 but zero hours of that was on autopilot. Different aircraft impose differing demands. An hour in PNG is worth about 20 at Morabbin. An hour in a fighter?

For what it's worth, I was lucky enough to have a pretty fast ride up the ladder in QF (at least for the first few years), and when I got my command, I had a grand total of 5,800 hours. I had cause to shut down an engine in flight only about 300 hours later.

 

[jb747]

That really surprises me, if I'm reading it correctly. I though the whole idea of check-lists is that it made you do every step, in order, reading it out, so things wouldn't be skipped, by for example, forgetting. If items 1-6 are done from memory, and you skip 3 and 4, but do 5 and 6, will it let you progress? What sort of things (in layman's terms) are done checked off by memory?

Even on a very electric jet like the A380, there are a number of checklists which contain memory items. This is stuff that is of such a time critical nature that you cannot afford the time to even pull up an electronically displayed checklist.

In QF30 we were on the way downhill in just over 20 seconds from the bang. If you needed to pull out a booklet, and then find the right page, it would take you about that long just to find the first action...not to have completed them. You do use the checklist when you get a chance to back up over the items to ensure you haven't missed anything.

 

[fairbasa]

The below is a post from PPRuNe. I can't verify the authenticity but supposedly it's from a US pilot union chair to AA pilots. It seems to provide a little more detail on the previously unknown 'MCAS' system unique to the MAX, including effect it can have. If it's true there's no mention of it in the Flight Manual it's slightly concerning.


posted on November 10, 2018 09:22
737 MAX8 Emergency Airworthiness Directive
The recently released Emergency Airworthiness Directive directs pilots how to deal with a known issue, but it does nothing to address the systems issues with the AOA system, which may be the causal system in the Lion Air accident. This is significant. The positive takeaway is that we are advised, as pilots, that once we recognize the issue, we can stop the negative impacts by taking the trim system out of the loop.

At the heart of this investigation is the MCAS system (description from Boeing):

MCAS (Maneuvering Characteristics Augmentation System) is implemented on the 737 MAX to enhance pitch characteristics with flaps UP and at elevated angles of attack. The MCAS function commands nose down stabilizer to enhance pitch characteristics during steep turns with elevated load factors and during flaps up flight at airspeeds approaching stall. MCAS is activated without pilot input and only operates in manual, flaps up flight. The system is designed to allow the flight crew to use column trim switch or stabilizer aislestand cutout switches to override MCAS input. The function is commanded by the Flight Control computer using input data from sensors and other airplane systems.

The MCAS function becomes active when the airplane Angle of Attack exceeds a threshold based on airspeed and altitude. Stabilizer incremental commands are limited to 2.5 degrees and are provided at a rate of 0.27 degrees per second. The magnitude of the stabilizer input is lower at high Mach number and greater at low Mach numbers. The function is reset once angle of attack falls below the Angle of Attack threshold or if manual stabilizer commands are provided by the flight crew. If the original elevated AOA condition persists, the MCAS function commands another incremental stabilizer nose down command according to current aircraft Mach number at actuation.

This is the first description you, as 737 pilots, have seen. It is not in the AA 737 Flight Manual Part 2, nor is there a description in the Boeing FCOM. It will be soon.

APA Safety recommends that you familiarize yourselves thoroughly with the information provided by CA xx_xx_X, 737 Fleet Captain, and the AA 737 fleet team. We have been working closely with CA xx_xx_X to get you accurate information as quickly as it becomes available. The AA 737 fleet team has placed this information in CCIs to 737 pilots, in bulletins, and in changes to flight documents.

At the present time, we have found no instances of AOA anomalies with our 737 MAX8 aircraft. That is positive news, but it is no assurance that the system will not fail. It is mechanical and software-driven. That is why pilots are at the controls.

Awareness is the key with all safety issues. You are aware this anomaly may occur and there is a mitigation procedure. No different than should you experience an engine failure.

As we continue to receive details, we will provide them in emails only to the 737 group. We chose to send this initial email to all pilots because it is a subject that is generating a great deal of interest.

Should you have questions, please do not hesitate to email or call us here at APA Safety: xx_-xx_-xx_X.

Captain xx_xx_X
DFW 737I
APA Safety Committee Chairman

 

[flyer89]

For what it's worth, I was lucky enough to have a pretty fast ride up the ladder in QF (at least for the first few years), and when I got my command, I had a grand total of 5,800 hours. I had cause to shut down an engine in flight only about 300 hours later.

Do you think that fast ride is resided to history at QF for young fellas my age? Even if you assume a best case scenario of fleet and network expansion?

 

[RooFlyer]

Even on a very electric jet like the A380, there are a number of checklists which contain memory items. This is stuff that is of such a time critical nature that you cannot afford the time to even pull up an electronically displayed checklist.

Thanks again. I was thinking only of checklists for regular takeoff and landing when I said I was surprised that there were ' memory items'. Certainly would want the emergency items memorised!

 

[Quickstatus]

Does anyone have a subscription to the WSJ?:
Some in the aviation industry are pointing the finger at Boeing for not including into the 737 Max flight manual a new flight control automated system that was not present in the 737 NG

 

[theblank]

here it is.

Boeing withheld crucial safety information on new 737 models, experts say

 

[fairbasa]

It sounds like that WSJ article is referring to the MCAS system quoted in the e-mail I posted, along with quoting the likely author from the APA.

 

[Quickstatus]

It sounds like that WSJ article is referring to the MCAS system quoted in the e-mail I posted, along with quoting the likely author from the APA.

Im not sure sounded like a WN pilot union rep.

 

[jb747]

It becomes more and more interesting.

For the life of me, I don’t understand why they would use trim to correct a condition of approaching the stall, when a stick pusher is such a tried and tested means. And having decided to go the way they did, supposedly to fulfill the FAA requirements for stall protection, you have to wonder why both Boeing and the FAA then didn’t mandate triplicated AoA systems.

But, it would still appear to a pilot to be runaway trim (it actually doesn’t matter what the cause is), so the procedure for controlling that would still be valid and appropriate.

 

[jb747]

Do you think that fast ride is resided to history at QF for young fellas my age? Even if you assume a best case scenario of fleet and network expansion?

Long gone. For anyone joining today, there are about 1,500 people between a new joiner and the most junior Captain. And for wide body, probably another 2-300 in waiting as well. On the other hand, the number of pilots who are 50 plus is vastly over represented (because of the on/off nature of their recruitment). So, I reckon that in about 15 years, a janitor will be able to get a command on day one.

 

[Quickstatus]

But, it would still appear to a pilot to be runaway trim (it actually doesn’t matter what the cause is), so the procedure for controlling that would still be valid and appropriate.

How common is this skill?

While the escape procedure is the same, the pilots would have never expected the aircraft to perform an uncommanded manouvre like this while they were flying in manual. So now there is now an emergency plus total confusion/ surprise/ shock at what the aircraft is doing. Makes 6 minutes seem like seconds.

 

[flyer89]

Long gone. For anyone joining today, there are about 1,500 people between a new joiner and the most junior Captain. And for wide body, probably another 2-300 in waiting as well. On the other hand, the number of pilots who are 50 plus is vastly over represented (because of the on/off nature of their recruitment). So, I reckon that in about 15 years, a janitor will be able to get a command on day one.

That’s not the worst outcome. A friend of ours who you no doubt know from the 380 got his command at the ripe old age of 32. Thought he was joking.....

 

[fairbasa]

It becomes more and more interesting.

For the life of me, I don’t understand why they would use trim to correct a condition of approaching the stall, when a stick pusher is such a tried and tested means. And having decided to go the way they did, supposedly to fulfill the FAA requirements for stall protection, you have to wonder why both Boeing and the FAA then didn’t mandate triplicated AoA systems.

But, it would still appear to a pilot to be runaway trim (it actually doesn’t matter what the cause is), so the procedure for controlling that would still be valid and appropriate.

I do wonder if the thought you posted earlier JB will prove to be relevant. I.e. what would happen if the pilots (not knowing about MCAS) went to hit the trim cut-out switches after the first nose down event, but not knowing another was coming 5 seconds later accidentally hit them at full nose down trim?

How quickly would the average flight crew realise what was going on and have the awareness to immediately pull out the manual trim handles to correct it? But as you mentioned before, why couldn't they use the yoke to correct for the full nose down trim until they worked out what was going on and manually trimmed?

 

[jb747]

.....There is an element of QF72 here - who has control of everything?.

Well, ultimately Kevin had control of his jet, as it reverted (or he forced it to) alternate law.

suspect it’s to sell aircraft to airlines. What better way than to tout the “safety” capabilities of the aircraft. Less pilot training and sim time required plus able to hire lower hour pilots = more pilot uptime, lower costs, better able to expand a fleet = more aircraft sold.

Very true. The dumbing of the profession. The designer of the A320 bragged that his aircraft could be flown by a milkman. The trouble is that airline execs, with no actual knowledge of aviation, believed him, and used this claim for their own agenda.

The A3xx series was rumoured to have been marketed as being impossible to stall and they did demonstrate it - in normal law. Did anyone ask for Stall protection to be demonstrated in degraded law. Unfortunately it was then demonstrated in real time with real passengers in degraded law...

There is nothing surprising in that. The aircraft can't be stalled in normal law, and that has some excellent ramifications in windshear or ground proximity events. We are all taught from day one that the other laws don't include such protection. Basically, they are Boeing mode (or at least the non FBW Boeings). Alternate and direct laws will give stall warnings, but otherwise the aircraft simply behave more or less as non FBW machines. The entire reason you're in the degraded laws is because the system has had some form of failure, and you don't want normal law operating in that case.

 

[jb747]

But as you mentioned before, why couldn't they use the yoke to correct for the full nose down trim until they worked out what was going on and manually trimmed?

Have a look at a plan view of any modern airliner. Trim is done my moving the entire tail surface, whilst elevator control is only a small fraction of the total area. In other words, trim is more powerful than an elevator input.

But, you'd expect with any control input that they'd be using the trim switches to help reduce the forces. And every time they did so, they should have had a 5 second window between the point where they stopped trimming, and the automatic system inhibit would cease. It might take a couple of cycles, but you'd expect someone would work out to use the cut off in one of those windows. My concern would be if they used it around the time the tail was in a nose down position.

 

[Quickstatus]

My concern would be if they used it around the time the tail was in a nose down position.

As in not enough aerodynamic capability to rescue the pitch attitude in the time /altitude remaining. Or the correction would break the aircraft?

 

[Quickstatus]

Do pilots ever tell management to not buy certain electronics enhancements in new purchases?

 

[AviatorInsight]

I do wonder if the thought you posted earlier JB will prove to be relevant. I.e. what would happen if the pilots (not knowing about MCAS) went to hit the trim cut-out switches after the first nose down event, but not knowing another was coming 5 seconds later accidentally hit them at full nose down trim?

How quickly would the average flight crew realise what was going on and have the awareness to immediately pull out the manual trim handles to correct it? But as you mentioned before, why couldn't they use the yoke to correct for the full nose down trim until they worked out what was going on and manually trimmed?

Moving the control column in the opposite direction to electric trim will stop the trim (at least in the NG). Failing that an uncommanded trim situation has occurred so you’d run through the runaway trim memory items. Cutting out the trim switches happens towards the end, but the last action is to physically grasp and hold the trim wheel.

I’ve been told the max trim system moves a lot quicker than the NG. Will be interesting to see when we get the max sim and I can see how much different it really is.