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Boeing 737 Max Recertification Testing - Finally.

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Boeing 737 Max Recertification Testing - Finally.

Old 5th Oct 2020, 09:01
  #381 (permalink)  
 
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BALPA said: "Requiring both crew members to turn the trim wheel simultaneously in a non-normal scenario is extremely undesirable and goes against all philosophies of having one pilot fly and one run the QRH [quick reference handbook: reading out the emergency checklist]. No flight control system should require both pilots to operate it at any stage, let alone in an emergency."
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Old 5th Oct 2020, 15:45
  #382 (permalink)  
 
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Originally Posted by clivegore View Post
BALPA said: "Requiring both crew members to turn the trim wheel simultaneously in a non-normal scenario is extremely undesirable and goes against all philosophies of having one pilot fly and one run the QRH [quick reference handbook: reading out the emergency checklist]. No flight control system should require both pilots to operate it at any stage, let alone in an emergency."
Please, I lost track where it says that both crewmembers need to turn the trimwheel.
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Old 5th Oct 2020, 16:35
  #383 (permalink)  
 
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Originally Posted by Flapsupbedsdown View Post
Please, I lost track where it says that both crewmembers need to turn the trimwheel.
Explained in simple terms here: UK pilots seek assurance on sensor and trim aspects of 737 Max redesign
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Old 5th Oct 2020, 16:36
  #384 (permalink)  
 
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"… both crew members need to turn the trim wheel "

This should not be required in the context of MCAS. The proposed modifications suggest that new protections will automatically inhibit the trim before such an extreme offset is reached. (NPA for comment)

With regards to a trim runaway, apart from MCAS, this remains a possibility in all 737 variants and continues to depend on quick recognition and action to inhibit the trim. If not then the two handed procedure would still be required, more so in those aircraft with the smaller diameter trim wheel. (Outside of the scope of the NPA ??)

The trim runaway is a debatable point with its reliance on crew awareness and quick intervention - shown to be insufficient in the MCAS accidents, but now argued as not being the same situation - HF aspects. If not, then would the combined crew effort on the trim wheel for recovery contravene certification requirements for all 737s.
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Old 5th Oct 2020, 16:46
  #385 (permalink)  
 
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There are non FBW aircrafts with no trim wheel
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Old 5th Oct 2020, 17:11
  #386 (permalink)  
 
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They are having a reversion system that does not depend on muscle power, I guess. If there is one where this is not the case, please name it!
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Old 5th Oct 2020, 17:21
  #387 (permalink)  

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I am right is saying that MCAS activation doesn't cause the trim wheel to operate, in which case it is fundamentally different from a stab trim runaway.
One of the things I loved on the 737 and missed on the 757 was the clanking stab trim that was a lovely early warning of speed instability, updrafts and down drafts. I always felt that having a silent trim activation on the 757 was cutting the pilot out of the loop.
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Old 5th Oct 2020, 17:22
  #388 (permalink)  
 
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Originally Posted by Flapsupbedsdown View Post
Please, I lost track where it says that both crewmembers need to turn the trimwheel.
https://www.faa.gov/news/media/attac...-R3-8-3-20.pdf

pg12-13
The Runaway Stabilizer checklist of the AFM is used when there is undesired movement of the airplane’s horizontal stabilizer. The FAA proposes revisions to the criteria for this checklist’s use, to include when uncommanded horizontal stabilizer movement occurs continuously or in a manner not appropriate for current flight conditions. The revised checklist would include an explicit recall item that instructs the flightcrew to use their thumb-actuated trim switch to reduce forces on the control column. The checklist would also include a recall item to use the control column and thrust levers to control the airplane’s pitch attitude and airspeed. Finally, the checklist would be revised to add a reference item to manually trim the horizontal stabilizer for pitch control, and note that a two-pilot effort may be used to correct an out-of-trim condition.
Surprised they didn't go as far as to recommend that a flight attendant be called to the cockpit as well. Did Dickson try out this procedure on his test flight does anyone know? What a mess.

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Old 5th Oct 2020, 17:46
  #389 (permalink)  
 
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sky9, operation of MCAS will move the trim wheel, which is limited in normal operation, and with a different, but manageable deviation for failure.
The trim runaway case is not constrained and thus requires pilot detection and inhibit switching.

Flapsupbedsdown, - 'There are non FBW aircrafts with no trim wheel.'
Yes, but they meet the certification requirements with higher levels of integrity and alternative means of operation.

B - 'Did Dickson try out this procedure on his test flight '
Why should he; a qualified 737 pilot should be familiar with the actions for trim runaway (not an NPA issue ?), although he could have considered the changed / clarified procedure wording (in the NPA).
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Old 5th Oct 2020, 19:12
  #390 (permalink)  
 
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Non-flying technical question

safetypee
You've referred to an "NPA" . . . . didn't recognize it at first but then, looking at the July 21 statement FAA issued, I found suggestion it stands for Notice of Proposed Action -- correct?

"CANIC & AD - The FAA will issue a Continued Airworthiness Notification to the International Community (CANIC) providing notice of pending significant safety actions and will publish a final Airworthiness Directive (AD) that addresses the known issues for grounding. The AD will advise operators of required corrective actions before aircraft may re-enter commercial service."
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Old 6th Oct 2020, 07:42
  #391 (permalink)  
 
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Willow, NPA ~ NPRM, yes
Sorry lapsed into Euro mode.
Thus for clarity, and for others whom I may have mislead:-

The FAA update page gives the history; 9/16/20 - 8/3/2020
https://www.faa.gov/news/updates/?newsId=93206

There is a link to the NPRM
https://www.faa.gov/news/media/attac...-R3-8-3-20.pdf

However, a further link to the review provides an easier read, particularly with the technical aspects and the rationale for the changes
https://www.faa.gov/news/media/attac...ummary-v-1.pdf

Thus 'what' changes are required are in the NPRM, and by exclusion what remains unchanged, which then leaves all those subjective issues requiring judgement by respective regulators; or even by public comment on the NPRM, i.e. BALPA.
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Old 6th Oct 2020, 13:06
  #392 (permalink)  
 
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Originally Posted by safetypeeFlapsupbedsdown, - '[i
There are non FBW aircrafts with no trim wheel[/i].'
Yes, but they meet the certification requirements with higher levels of integrity and alternative means of operation..
Was many years ago but can't recall "alternative means of operation" on the 75/76 stabilizer once the cut-out switches are plced to "CUT-OUT".
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Old 6th Oct 2020, 13:36
  #393 (permalink)  
 
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Two actuators to be cut out independently from each other, with trim running at half speed if done so?
And alternate trim command overriding all other commands from the center pedestal?
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Old 6th Oct 2020, 17:41
  #394 (permalink)  
 
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Thanks safetypee for clarification.

Substantive question, with regard to the operation of the trim wheel, and at least the objection (if that is a proper term here) of BALPA about the possibility of both pilots having to go hands-on to counter forces on the stabilizer: In this potential situation, are the risks relating to the trim wheel capable of being mitigated or even retired completely through specific training exercises? The return to service is built, in large part, upon creating augmented training components for pilots and upon the operators following through on conducting those trainings faithfully.

The potential situation of the PNF having also to go hands-on with the trim wheel would be, in and of itself, something "non-normal" - correct? Nevertheless, can the risks it presents be sufficiently reduced by means of a very specific element in the forthcoming training adaptations for the returned 737 MAX (and conceivably for other variants if applicable)?
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Old 6th Oct 2020, 19:48
  #395 (permalink)  
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I wonder how this 2-men effort in an emergency will be translated in the SOPs. Does it mean that 2 persons must be physically in their respective seats at all times ? Emergency or serious situations occurring when only one pilot was in the cockpit are no so rare.as one thinks . Even accidents , the Ueberlingen Collison is a prime example. Are we going to see measures like the ( thanks God) short lived ones taken after Germanwings, i.e. a flight attendant having to replace a pilot leaving the cockpit ?
Or as I suspect, it will be a note somewhere saying to minimize the time off the cockpit to a minimum , counting on the law of probabilities to save the day.
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Old 6th Oct 2020, 23:33
  #396 (permalink)  
 
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The following draft on Training is open to comment until Nov. so I suspect the earliest one would see a final document would be in Jan 2021.
FAA Updates on Boeing 737 MAX10/6/2020

The FAA posted the draft Flight Standardization Board (FSB) report on the proposed pilot training for the Boeing 737 MAX this afternoon. It can be found here under FSBR B737



The report incorporates the recommendations from the Joint Operations Evaluation Board (JOEB) which recently met for nine days. The JOEB was comprised of civil aviation authorities from the United States, Canada, Brazil, and the European Union.

The comment period on the draft FSB report will last through November 2, 2020. The FAA will publish a final FSB report after reviewing and addressing public comments on the draft FSB Report.
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Old 7th Oct 2020, 02:37
  #397 (permalink)  
 
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Does the usage in the FSB Report (rev. 17) of the term SLF, meaning Supervised Line Flying, mean that SLF here needs to be differentiated, from now on?

Wondering what the actual aviators conclude about the pertinent questions and issues, when they've read the "Special Emphasis Areas" (Section 9.2, pp. 9-11); as well as Appendix 7, "Special Training for Flightcrews" of the 737 MAX (pp.65-67) ("No pilot may operate the 737 MAX unless the following ground and flight training specified in this appendix has been completed.")

Logically and based on the structure of the Report, even an uninitiated observer (SLF, of the Forum definition) can conclude that operators already have very high fidelity with extensively detailed training requirements. This set of requirements, though, at least makes it relevant to ask, are operators of the 737 MAX ready, willing and equipped - in terms of both personnel and equipment - to perform all of the tasks? (And then there's the pandemic's airline depression. . . .)

A small detail point: Appendix 3, "Differences Tables", uses an abbreviation or acronym not identified in the document, near as SLF-WR can tell: ATA. What it is, s'il vous plait?
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Old 7th Oct 2020, 05:16
  #398 (permalink)  
 
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ATA = Airline Transport of America system chapter code. The unique aspect of the chapter numbers is its relevance for all aircraft. Thus a chapter reference number for a Boeing 747 will be the same for other Boeing aircraft, a BAe 125 and Airbus Aircraft. Examples of this include Oxygen (Chapter 35), Electrical Power (Chapter 24) and Doors (Chapter 52).
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Old 7th Oct 2020, 07:41
  #399 (permalink)  
 
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Now superseded by JASC (Joint Aircraft System/Component Code), ATA 100 was one of the specifications developed by the Air Transport Association of America.

It's a 3-part code used in Maintenance Manuals, Parts Catalogues and other technical documentation, of which the first part (Chapter) and usuallu the second part (Sub-Chapter) is common across most of the industry. So, for example, a mechanic pretty well anywhere will recognise that 32-40-nn is where to find information on Landing Gear -> Wheels & Brakes.
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Old 7th Oct 2020, 13:12
  #400 (permalink)  
 
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Willow, #394,
"In this potential situation, are the risks relating to the trim wheel [requiring two-pilot effort*] capable of being mitigated or even retired completely through specific training exercises? " * NPRM wording: - two hands or four hands ?

A guiding principle^^ is that training should not be used to mitigate a technical shortcoming; but principles come and go. (^^ a misnomer).
I doubt that there is a satisfactory answer because the situation depends on assumed probabilities, subjective interpretation of requirements, and the variability of human behaviour both in the regulatory process and ultimately operation.

In such circumstances we may be asking the wrong question.
Changing the viewpoint from the human as a hazard - to be trained, constrained, and ultimately blamed; to that of the human as a help, people who can learn in everyday operation, adapt to unforeseen situations, and thus improve safety by minimising overall risk.

The new memory checklist concentrates on using the stick-top trim switch, fly the aircraft, actions which are assumed to be instinctive. These skills can be practiced during manual flight (A/T Off), normal operations, getting the feel for the aircraft, relating trim change with speed, thrust, config change.
There could be greater safety benefit by encouraging pilots to think and learn from opportunities in normal operations - self education, experience, professionalism, airmanship, so that if a trim runaway is encountered, then the pilot will react as assumed by the checklist, instinctively and sufficiently quickly to avoid a more extreme and improbable situation. ##

Similarly the regulators and manufacturers need to change how they consider piloting contributions to safety; a help, not a hazard, a safety resource; to be used before the event, not to resolve a situation which design and regulation should prevent.
Reconsider the assumptions made about the human and operating environment, the rationales; take in the 'big picture' of aviation safety - look both ways before crossing the road - every day, normal operation.

## 'New' Emergency drill memory items Trim Runaway: -
'Firmly hold control column.
Disengage autopilot if engaged. Disengage autothrottle if engaged.
Use the control column and thrust levers to control airplane pitch attitude and airspeed.
Use main electric stabilizer trim to reduce control column forces'.


In my flying days that text described disconnecting the autos and flying manually.
.

Last edited by safetypee; 7th Oct 2020 at 16:00.
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