When a company SOP deliberately contradicts FCTM advice without valid reason.

[Tee Emm]

One of the domestic airlines operating the B737NG is XXX. It is company SOP to have the autothrottle armed at all times in order to permit low speed protection. On a manually flown landing the pilot is permitted to deselect "Speed" so that manual throttle operation is not impeded but the AT `Arm` switch is left engaged.
This is in direct contradiction of the advice given in the B737NG FCTM that states: "The autothrottle ARM mode is normally not recommended because its function can be confusing. The primary feature the autothrottle ARM mode provides is minimum speed protection in the event the airplane slows to minimum maneuvering speed. Other features normally associated with the autothrottle, such as gust protection, are not provided"

Company management obviously made a courageous decision to display professional disinterest in the Boeing FCTM recommendation. But it makes you wonder why someone should ignore the FCTM when the reason why the recommendation is published is clearly stated in black and white. :ugh:

[Sciolistes]

Absolutely no criticism of your rationale, as I agree that SOPs should be in line with the FCTM to have credibility, but I never understood how the A/T in ARM can be confusing and I can understand why VB might want to use the feature, providing they provide info/training to ensure that nobody is confused.

[latetonite]

The Boeing Company is protecting itself from the law by stating this in the FCTM, as there have been longer flares due inadvertent trottle movement during landing.
The Airline is aware of the odd go-around going wrong without proper thrust setting, and implements the landing procedure with A/T armed.
My previous carrier publishes only dual autopilot approaches in VOL 1 to circumnavigate this responsibility.
Pilots are getting confused are they think they can fly planes safely while monkey flying SOP`s.
At the end of the day, flying remains still a profession.

[mutt]

Generally an airline will write to Boeing with their proposed amendment, Boeing will issue a "No Technical Objection" if they accept the proposal.

How do you know that VB didn't do this?

Mutt

[rudolf]

The FCTM says not recommended rather than forbidden, as long as there is guidance on how the ARM function works then I don't see a problem. I fly for an airline that regularly uses this to provide low speed protection, however, we recommend not using it in gusty conditions because of the increased risk of it activating.

Can't speak for Australia but in Europe an NTO is no longer needed, as long as a risk assessment has been carried out then this will suffice.

[Denti]

We did receive a NTO when we started this 20 years ago. Boeing advised us that additional training during initial type rating would be a good idea which was incorporated into the type rating syllabus.

We never had a long landing incident because of inadvertent A/T activation, rather the opposite in some cases as the A/T reverts to landing retard mode below 27ft if it is active.

As stated above it is a good idea to switch it off completely in gusty conditions, apart from that it is an absolute non-issue.

[galdian]

Been stated before but years ago Boeing instructors stated that as 737 was often first/level entry jet then work on KISS principle ie all automatics either OFF or ON...HOWEVER in airlines with proper/sufficient training of various options available (in this case Autothrottle ARM rather than DISCONNECT) then fill your boots and use the features Boeing have made available to the maximum extent.

Monitoring rather than flying safer says Mr Boeing - makes sense.

Above applies to Control Wheel Steering, another great asset but for too many (sometimes people, sometimes authorities) simply white mans magic; all another story.

Cheers.

[Zorin_75]

have the autothrottle armed at all times in order to permit low speed protection Isn't that a valid reason right there?

[sheppey]

Quote:
have the autothrottle armed at all times in order to permit low speed protection
Isn't that a valid reason right there?

Obviously not - since the latest 737 FCTM revision July 2011 still has the same recommendation it has had for decades of 737 operation and that is `autothrottle ARM mode is normally not recommended`. Obviously Boeing is on to something there or else what is the point of the "not recommended"? Some would argue it is better to go with the strength and accept the Boeing recommendations rather than open yourself to litigation if something went wrong. Lawyers are good at that sort of opening.

[Checkboard]

makes you wonder why someone should ignore the FCTM when the reason why the recommendation is published is clearly stated in black and white.
... because the opinion of the Boeing pilot who wrote the FCTM isn't chiseled into a stone tablet and brought down from Mount Olympus. :8

Just because it's an opinion from the manufacturer, it doesn't mean it's necessarily the best practice for EVERY operation around the world ... :ugh:

[RainingLogic]

So do you think Boeing and Airbus designed their jumbos for 200 hour pilots?

[c100driver]

The real reason as was told to me is the possibility of tail strike as the thrust increases inadvertently at low level if you drop below min spd.

This was disucssed at a Boeing conference our fleet team attended and the Boeing flight test guys were all convinced that "all on" or "all off" is the best way to operate the machine. The Boeing guys even demonstrated the issue in the simulator to the head sheds from the training department.

Not long after that our FCOM was changed to all on or all off.

[Centaurus]

So what actually happens if the A/T Arm is left on during final approach and the pilot is using manual thrust? For example if Vref 40 is (say) 130 knots and the pilot crosses the fence exactly on Vref, do the throttles go forward to prevent the aircraft from going below Vref? After all the FCTM allows for a speed range between Vref to Vref minus 5 knots for touch down.

On a similar vein if perchance the aircraft floats with speed bleeding a few knots below Vref during the float - again do the throttles advance just when you don't want them to? And if unrestrained, how much is thrust (N1) is increased. It must be distracting for the PF when he feels the thrust levers opening up under his hand while he is manually controlling them. Seems to me Boeing made a wise decision in advising switching off the ARM mode for manual thrust:D

[Sciolistes]

Just reviwed fcom2 and it looks like min speed reversion works differently for different approaches and can kick in at 1.3vs (not 1.3g!). it certainly can be confusing.

[BOAC]

Centaurus and others - 'HC' to all - this 'argument' has gone around the houses at airlines and here before. (Did I mean 'discussion'...?:rolleyes:)

Many years ago I produced a table for my 'then airline' demonstrating that if you flew correct speeds on finals, particularly at F40, the A/T would 'cut in'. It was dismissed, since - well no-one does, do they.? The 27'RA stops it 'cutting in' on an otherwise 'normal' flare thus eliminating the 'tailscrape' theory, but I flew with one 'senior' (in all respects:)) TC who often 'began' the flare ABOVE 27RA and we performed a terrific fly-by of the airport to tumultuous applause from the spectators.................

I eventually learned to live with it, disconnecting it around 1-200'ish when visual. The 'advantages' put to me (rolled up newspaper style) are significant:

Min speed reversion (a guarded 'plus' - ask THY)
The option of a reduced power 'auto' g/a (in manual A/T Full Power is required)

[Denti]

I guess BOAC meant the fact that the A/T does no longer provide min speed reversion below 27ft RA and instead goes into landing retard mode. Which is exactly what happened to those THY guys because the left RA showed below 27ft.

On the NG i haven't had the A/T cutting in smooth air when flown at the correct speeds, however in gusty weather it is quite common and usually solved by a simple click on the disconnect button.

[BOAC]

Alpa - THY - I know - hence the words 'a guarded plus' - it is well to be aware of the function of the RA on ANY A/T mode in the 737, in particular the false <27'RA that killed them..

Re G/A power- the 'first push' gives a CERTIFIED 2-eng g/a power and hence it is 'acceptable' for regulatory purposes for G/A. I reckon you (and all) would be incapable of working out the correct manual N1 for the min 2000fpm climb - right? Hence the need for Full Power on a manual G/A - find yourself an IRE and ask. If you do not do that you should fail an IR (in the UK anyway). I don't know about your 'land', of course.

Regarding your last two points, the answers are in the thread in which you have posted. If you do not know the Stick Shaker margins............................

Merry Christmas to you too.

[Centaurus]

while simultaneously establishing an initial pitch attitude of around 12 degrees

From 737 FCTM: ..".ensure/set go-around thrust and rotate smoothly towards 15 degrees"

[BOAC]

I have long arms, so the resulting N1 will be approximatly 85-90%. - and you are absolutely certain that '85%'ish' will give you the required rate of climb at +25deg and MLW and 2000' ASL? If you are using manual throttle, best to push them forwards and then have PNF set them to the bugs, then it will.

Part of the 'problems' in turbulent conditions arise from the use of the alpha vane to 'measure' 1.3Vs and that can bounce around a bit.

[cosmo kramer]

Alpagueur320,
FCOM2 Chapter 4:
Minimum speed is based on angle of attack and is approximately 1.3 Vs for the current flap configuration. It is sensed by the angle of attack vanes, one on either side of the forward fuselage.
Hence, with G-loading from bank and gusts, even when on correct speed, the stall speed may increase and factored with 1.3 may exceed commanded speed. Amazing that the proponents of this feature have been unable to give this simple answer, despite being asked several times.

I completely agree with you about setting go-around thrust. A well (normally) trained pilot should be perfectly capable of manually (gosh!) adjusting the thrust levers that the result is 1000-2000 feet pr. minute just like the auto throttle would have.

BOAC,
the auto throttle is does exactly what written above (gives you an arbitrary rate between 1000-2000 feet pr. min). It's not certified in any way and is no way guaranteed to give you exactly 2000 fpm. YOU have to figure out if 1000-2000 fpm is enough to meet the required climb gradient for the missed approach. Obviously mostly it would be.

Further, I would be very interested if you can point me to the document that says that I am required to set full go-around thrust in my vastly overpowered aircraft. All the documents I have seen says that I must to meet the required gradient for the missed approach.

[mohdawang]

This is in direct contradiction of the advice given in the B737NG FCTM that states: "The autothrottle ARM mode is normally not recommended because its function can be confusing. The primary feature the autothrottle ARM mode provides is minimum speed protection in the event the airplane slows to minimum maneuvering speed. Other features normally associated with the autothrottle, such as gust protection, are not provided"

Flew the B737-300/4400/500 for umpteen years with approach and landing accomplished with autothrottles in arm and speed mode deselected with no problems even in really gusty conditions during pre typhoon and post typhoon phases in Manila and Kai Tak Hong Kong. It only happened once when the F/O flared high with speed dropping back below Vref, so we accomplished a go around.

[PantLoad]

Well, I ran in the rat race for several decades....pretty much been around the block once or twice. And, I've seen guys like you come an go....nothing new.

Glad you have superior knowledge of airline operations and superior knowledge of how to operate your aircraft, as well. Chuck Yeager and Bob Hoover are proud of you, no doubt.

You see, for an airline to operate, they need an airline operating certificate. One of the requirements to obtain and retain an airline operating certificate (and there are many hoops to jump through) is to have an SOP. The SOP has to be approved by the authorities who grant the airline operating certificate.

Now, the SOP....approved....has to be clear, taught to all, followed by all, and checked that all know and follow it. This is one of the requirements of the airline operating certificate.

Whether or not individual pilots agree with the SOP is totally irrelevant. And, no one cares what you think. All that matters is that the airline operating certifcate stays in force, so the people at the top can fill their pockets with money.

The SOP trumps any other procedure....including manufacturers suggested practices. Adherece to the SOP is mandatory and is paramount to maintaining the issued airline operating certificate.

If you feel there need to be improvements to your company's SOP, you should voice your opinion to the appropriate authorities within your airline. Good luck....changes are few and slow to occur. (for many reasons)

If you feel you can't live with the SOPs (You think they're stupid, crazy, etc.), you should leave....go to another airlines where the SOPs are 'better'....or, start your own airline.

Yep, seen this before....


Fly safe,


PantLoad

[john_tullamarine]

Following on from Mutt's comments, it is accepted that limitations and regulations are prescriptive while remaining material is recommended.

One needs to have made due consideration of the OEM's recommended practices but there is no magic formula which says that an operator must operate strictly in accordance with the OEM's way of doing things. Indeed many operators over the years have made an art form of doing things differently according to their own perceptions which may vary according to who is in the chair from time to time.

NTO is a traditional way of seeking OEM de facto concurrence with alternative ways of doing things ..

[BOAC]

I have to bow out now due to total confusion from alpa's para 1 - I wish I could understand what he/she is trying to say.

Further, I would be very interested if you can point me to the document that says that I am required to set full go-around thrust in my vastly overpowered aircraft. All the documents I have seen says that I must to meet the required gradient for the missed approach. - cannot help you there. It was 'told' to me by a BA UK trained TIRE and I do not always rush to a website to try and find 'written proof' - I generally believe what I am told. Pant Load's post is worth a read. Providing, I suppose, you fully brief the required g/a rate of climb (not gradient!) in your approach briefing AND brief PNF to monitor that you are achieving it, I bow to your superior skills. I found it easier to either apply full power to start the 'up' OR use the one-push A/T setting, knowing it would be achieved. Furthermore the stalling AoA may increase - I think you will find it stays the same unless you are re-writing aerodynamics. It is the detected AoA that can 'increase'.

A reminder that this topic has been done to death before here too. Comment from a UK TIRE on the regulatory aspects of manual g/a power would be useful. I guess the rules may have changed.

[cosmo kramer]

BOAC,
The 737 has instant Vertical Speed. Which part in setting thrust to achieve a specific Vertical speed is difficult and requires superior airmanship?

I found it easier to either apply full power to start the 'up' OR use the one-push A/T setting, knowing it would be achieved.
That you find it easier, doesn't make it certified.


* Edited previous post to say speed instead of AoA.

[PantLoad]

Yes, good point. I misspelled 'adherence.'


Fly safe,


PantLoad

[Capn Bloggs]

"8.0.2.3 A significant number of operating practices allow the discretion to the Commander to decide how the flight should be flown. These are characterised with the need to exercise sound judgement and prudent assessment and may be referred to as sound operating practises (included under the more general heading of airmanship during an earlier period).
There has been a trend within the industry to refer to all operating activity under the heading of SOPs or a desire to specify all procedures within such a concept. Such broadening of the scope of SOPs diminishes the merit and value of the concept and hence the need to highlight this differentiation."

Well said (or written). :D

[RAT 5]

This operation of A/T on App has been discussed at depth before. If memory serves me well (13 years ago) it is this way on B757/767. When I transferred to B733 many asked why we could not fly in 'SPD deselected'. These were old B757/767 pilots. Trouble was the C.P didn't understand the question. However, some had experimented on the line and found it worked just fine. I didn't so have no diect knowledge of it. You can disconnect at flare I supose. Anyway, said C.P asked Boeing. Answer, not recommended. However, from flying these types it seemed Boeing flight dept's don't talk to each other that much. Advancements in later design didn't seem to filter down to earlier types, when suitable. It seems B737 line pilots fall into 2 categories, but Boeing only 1.
Moving on: about manual flight = all on, all off. IMHO that is not always wise. On B733 the TCAS manoeuvre was A/P OFF and follow guidance. Now, the NG is disconnect A/T as well. When a Boeing pilot was asked that surely this introduced a safety (speed control) threat and was a retrograde step, the reply came that Boeing has adopted the philosophy of 'all on or all off all the time' The argument of having seen dangerous developments in the sim with bad speed control, absurd ROC's, forgetting to re-engage A/T after RA, etc. met with little appreciation. Why disconnect A/T if having a CLB RA above 25,000 and then forgetting to add enough thrust; or going full power at low level and hitting 3000fpm in a crowded TMA. DAFT. So, IMHO, Boeing doesn't always have the be all and end all opinion. They changed what was a safe action into a less safe one, so as to conform to a pedantic philosophy. I hear of one airline that teaches manual approaches with A/T engaged until stabalised in final config. I assume they asked Boeing?

[Centaurus]

Why disconnect A/T if having a CLB RA above 25,000 and then forgetting to add enough thrust; or going full power at low level and hitting 3000fpm in a crowded TMA. DAFT. So, IMHO, Boeing doesn't always have the be all and end all opinion

Are you talking about incompetent pilots or competent pilots? Boeing assume the latter otherwise they would have to re-write all their manuals.


The current FCTM 737 Classic states: "RA maneuvers require only small pitch attitude changes which should be accomplished smoothly and without delay. Properly executed, the RA maneuver is mild and does not require large or abrupt control movements. Remember the passengers and flight attendants may not be all seated during this maneuver."

[RAT 5]

Centaurus,

It is easy for Boeing to sit in an office and write this stuff. As has been seen many times it is the human behaviour, or perhaps misbehaviour, that contributes to most accidents. In that split second moment of panic, the PF, who might be quite inexperienced, (think rapidly expanding airlines, long range cruise pilots 1/2 asleep etc.) is not always going to react in the calm relaxed manner envisaged by those who wrote the manuals. When you think you are about to die people react in extremes and full back stick and full power is just such a reaction. Worse would be full back stick and no power. What has happened in real life is excessive nose down pitch with further proof that Newton's laws of motion are alive and well. People under stress do not always react the way the manual says they should. Removing one safety net does not IMHO seem the best way to go. Remember my basic point; it was changed from B737CL to B737NG and I cant understand why. It did not improve matters.

[LeadSled]

Can't speak for Australia but in Europe an NTO is no longer needed, as long as a risk assessment has been carried out then this will suffice. Rudolph, ( and J T)
As you certain of that, legally??

Any modification of procedures that form part of the AFM are part of the certification, and any change is, in legal terms, a change to the certification standards.

In a recent much publicized incident in Australia, it transpired that the operator had made a unilateral change to an AFM published procedure, in this case a missed approach.

When Airbus were approached for a retrospective "approval" of the change, the answer was (in effect) "No, you are bound by the AFM ( or equivalent) as part of the aircraft certification".

Quite apart from the fact that few, if any, operators would have as much data as the original manufacturer to do an adequate risk assessment, this is an area where the legal issues are not well understood, including by regulatory authority staff.

In Australia, the regulations are very clear, operators are required to comply with all provisions of the AFM. This provision is only over-ridden by the emergency authority of the pilot in command --- as affirmed by a superior court decision.

Tootle pip!!

[4dogs]

Leadsled.

Any modification of procedures that form part of the AFM are part of the certification, and any change is, in legal terms, a change to the certification standards.

I'm not sure of your logic (post hoc ergo propter hoc?), since the standards only require that some procedures must be provided - subsequently altering those procedures has no effect on the certification standards, but it does have an effect on compliance therewith. That will form the basis of an interesting debate in a suitable court.

The procedures in an AFM are not exclusive - they have never purported to cover everything (see FAR 25.1585(b) for a start) and they are not necessarily published as two-crew PF/PM procedures. If we were to follow your logic, an OEM NTO would be worthless unless also approved by the NAA which approved the original AFM - a somewhat mindless process to contemplate in any value-adding sense!

When Airbus were approached for a retrospective "approval" of the change, the answer was (in effect) "No, you are bound by the AFM ( or equivalent) as part of the aircraft certification".

I do not believe that the Airbus response took that line at all - rather it rejected the suggested procedure as inappropriate from an operational rather than legal perspective. Would you mind quoting that bit of the Airbus response which you believe supports your statement?

Quite apart from the fact that few, if any, operators would have as much data as the original manufacturer to do an adequate risk assessment, this is an area where the legal issues are not well understood, including by regulatory authority staff.

Generally so, but not always. I wouldn't mind a quid for every time the aircraft does not do what the OEM said it would do, a problem arises in an area not explored in meeting certification requirements or a change of players within the operations area of the OEM results in a new set of personal beliefs becoming "law". Most lawyers have no idea of the practical limitations of these OEM "Sermons on the Mount".

In Australia, the regulations are very clear, operators are required to comply with all provisions of the AFM. This provision is only over-ridden by the emergency authority of the pilot in command --- as affirmed by a superior court decision.

Yes, CAR 138(1) requires: "If a flight manual has been issued for an Australian aircraft, the pilot in command of the aircraft must comply with a requirement, instruction, procedure or limitation concerning the operation of the aircraft that is set out in the manual." But, in parallel, CAR 232 requires a CASA-approved "flight check system" to be developed and used - with no proscription on varying AFM procedures. So, your "very clear" is not so clear and the "emergency authority" granted in CAR 145 to the pilot in command has significant limits in its scope.

But what I am really interested in is:

---as affirmed by a superior court decision.

Could you please provide a reference to this decision?

Stay Alive,