vilas

BUBBERES44
There are pilots, pilots and pilots. In a 737 pilot came high and fast in VMC with speed brakes did a 360 stalled and killed everyone. In A320 with Alpha floor TOGA is set and speed brakes go in. That is protection. What's your problem? Air India express crash new 737-800 ATC cleared descent late due approach radar NA. 7000 ft vertical offset.. Expat Pilot didn't do anything to descent faster. Almost same offset through the approach, at 1DME dived 4000ft/mt.despite the pleas of the FO to go round, touchdown deep, reversed and went round sorry went down the hill 150 dead. What automation got to do with this? So stop your cry in wilderness the aviation has changed Boeing included. 737s will take their place in history along with Tigermoth, DC3,707 and 747 classic ( I was a captain on).

Owain Glyndwr

Machinbird

We seem to have been slightly at cross purposes. My remarks were aimed specifically at the minimal changes necessary to fix the stall warning anomaly whereas I now recognise that you had a more general application in mind.

For sure if you have no IAS information you cannot work an autothrottle system, but I don't think the problem is one of setting gains for the flight control system. The current system reverts to a constant gain setting I believe, which is perfectly adequate to fly the aircraft. The only change (in pitch at least) is that the response time may vary with altitude as it does on conventional aircraft rather than being constant in all flight phases. The problem, as I understand it, would be to find a way to maintain the envelope protection functions. Dozy has made the point several times, and I can but reinforce his comments that one really should differentiate between the "handling laws" and envelope protection functions. Lumping them together under the general label of "laws" tends to obscure important features

A33Zab

Alpha floor protection:

This function enhances windshear survivability.

Alpha floor detection is available from lift off to a 100ft RA in approach.

When the alpha floor condition is activated, the FCPCs send a signal to the
FMGECs(Autothrust Function)which controls the TO/GA engine thrust, whatever the throttle control lever position.

The activation conditions are:

• Alpha filtered (3s) greater than a threshold depending on aircraft configuration, the GS variation and the difference between GS and airspeed.

or

• SS NU demand <-14° and theta >25°

or

• SS NU demand <-14°and alpha protection.

Alpha floor is inhibited when Mach is above 0.53

The Alpha floor can also be inhibited by the FMGEC under certain engine failure conditions with flaps extended.

(When a TLA is below 5° the system may consider the engine failed and therefore alpha floor may be inhibited)

Alpha Floor is displayed A.FLOOR on the FMA (in green and amber boxed) and at LH upper area of EWD.

Alpha lock function:

If alpha exceeds 8.5° or the speed goes below 148 kt, the slat retraction from position 1 to 0 is inhibited.

This inhibition is removed whenalpha goes below 8.2° and when the speed exceeds154 kt, in this case the slats automatically retract to 0.

Alpha lock activation isdisplayed as pulsing A LOCK instead of the regular S indication of the S/F positionindicator on the EWD.

Thealpha lock function is not active after the S/F lever has been set to 0.

roulishollandais

Thank you A33Zab for these two clear mementos.

Why is the final design of Airbus and Dreamliner full of failures, weakenesses and non-K.I.S.S. conception when not Babel's Tower chating in the manuals and enquiries? Engineers, please, do less, fire the bad built brains. Pilots have not hours and months to take decisions and chose or know about all these laws born in competition of office without taking the risk.

Passengers paying their ticket and sitting in the Cabin with smiling steward(esse)s are hostage of the Menkind's curiosity trusting in goodfaith from engineers and are allowed to think that presence of pilots in the cockpit are warantees for their own lifes. That is the first difference between fighters and airliners.

Gums, yes, said it already -as everything in our hamsterwheel- but really he is emphasizing the fact that they are too many and unknown - included in the official report - different flight laws and conditions to go from one to another and how. And, in that, fighters are not different from airliners. All the pilots, military and cvilian, are in their right to request the engineers do their best to keep them alive, included if it means pilots chose to reject the last wonderinvention. That has a name : Freedom.

DozyWannabe

In systems design terms, the Airbus design is very much built on the KISS principle, it's just that airliners are by their very nature complex devices and thus even a simplified interface will appear complex.

While I think it's imperative that a pilot should be as knowledgeable about their aircraft as practical, there is no need to fathom the minutae of the flight control/handling "Laws" in order to fly the aircraft, even in a degraded state. Putting the envelope protections to one side, it may be helpful to think of those systems as performing the function of a flight engineer - and in a crisis situation all you need to remember is that all of the laws are designed to provide an aircraft which handles as close as possible to the way it would if everything was working correctly. As long as the aircraft is handled gingerly and with care, there should be very little standing in the way of her bringing you and your passengers to the ground safely.

EDIT: Additionally, I couldn't help but notice something recently. When an A320 scraped a wingtip on landing, the discussion from some parties was all about how interconnected yokes would have solved the problem, and yet when a similar incident happened on that SWA 737 (which has interconnected yokes) recently a lot of the same posters acted as judge, jury and executioner to the Captain. Double standards much?

exeng

Do you remember Aeroperu 603 and Birgenair 301? Both B.757's with blocked pitots which both ended in tragedy in 1996. Both accidents were it seems due to the two aces up front not recognising the unusual pitch attitude and allowing the aircraft to stall.

So not so different to the AF Airbus situation on the face of it.

I've flown numerous Boeing types in all seats plus the A320. To be honest I happen to prefer the Boeing philosophy, and for me the 777 FBW was in some ways better than the Airbus FBW - although both have their advantages and disadvantages.

With all aircraft types knowing the appropriate pitch attitude and power setting for a given configuration is always important.

We all use automation for obvious reasons. But average to good pilots, whether Airbus or Boeing will be able to fly the aeroplane when the sh*t hit the fan.

Thing is Bubbers these days we do all need automation because I fail to see how well any of us would fare flying an 8 to 16 hour sector in RVSM (which would not be allowed anyway), or a multi sector day (in RVSM). I flew six sectors today in a little 737 and was very grateful for the A/P. I flew 2 sectors the other day with both A/P's inop (Stab trim unit) and it was quite hard work, particularly given the weather here in West Africa - the F/O and I never exceeded a 30 ft deviation but the normal task allocation and work sharing went to hell in a handcart. Give me an A/P any day on any aircraft.

I suspect there have many incidents similar to AF 447 that have occurred on both Airbus and Boeing where there was a happy outcome - thing is those incidents don't tend to hit the headlines.

roulishollandais

@DozyWannabe
Perhaps Airbus tries to use K.I.S.S. principles, but the result is all but "simple". Since four years posters are unable to get a complete list of the flight laws, that list seems long like a day without bread, they are thousand (perhaps a little less I agree) exceptions, inhibitions, considerations, litterary-philosophical descriptions instead of equations. No reason to think that in a normal flight things are simpler they are only hidden until they pop-up when the captain takes his rest crossing Inter Topical Front and then all these hidden things, appear with an orchester of warnings and alarms, THS does is dance alone, zoom climbs appear, Wonderful! Everything but simple in the final "design" . Something works not as wanted!

Boeing is not better with his dreamliner. The idea to use these Li-Ion batteries seemed to be K.I.S.S. Now we see them reparing the burned fuselage in Heathrow...(not in! out! winter coming, inventing how to repare carbon fiber and inject resine, and losing much money, but at the end it will be said Crew are expensive and dangerous... etc. etc.

Today nor Airbus nor Boeing keep it simple in facts and result. It is theory, dream and narcicism.

And airlines don't do better : I cannot trust it , I read that more than 500 Air France people are supervising so said "human factors", how is that possible? Asiana tried an ultimate simplification : no more show outside at landing and don't push throttles.

You are right if you say it is sarcastic, but isn't it time to wake up and see that reality is diverging from the wants and wills?

Still an exemple : despite A33Zab does the best he can to do the things simpler, clearer, he had to write that sentence : "The Alpha floor can also be inhibited by the FMGEC under certain engine failure conditions with flaps extended". Why all these secrecy theater? I suppose these "certain conditions" are no so simple.

Double standard? At theater every actor plays a role.

tdracer

exeng

Perhaps nit-picking, but Aeroperu was not due to blocked pitots, it was due to blocked statics (due to maintenance failing to remove protective tape after washing the airplane). Lost of static pressure is far worse since it effectively wipes out airspeed and altitude. I felt sorry for Aeroperu flight crew since there would be no flight deck indication of a problem until after takeoff - unlike Birgenair where they continued with takeoff knowing full well there was a major problem with airspeed.

Also, if I recall correctly, Aeroperu did not stall, it hit the water in controlled flight because air traffic (not realizing the transponder was corrupted by the same static pressure problem as the flight deck instruments) told them they were flying much higher than they were.

However Birgenair was a prime example of the pilot flying totally ignoring what the other pilots in the flight deck were trying to tell him...

DozyWannabe

The list has appeared several times over the course of these threads, try the search function.

Oh, believe me there are equations - I've seen a lot of them! But they wouldn't make sense to anyone without a background in software engineering, just as most pilots without an engineering or mathematical background would not fully understand all the physics equations in HTBJ without Dai Davies' prose explaining it to them.

Nothing's hidden. Throughout the sequence the aircraft did it's level best to tell the crew what was happening - from the initial "ADR DISAGREE" on the ECAM, through the Stall Warning sounding for over a minute - finally to the rapidly unwinding altimeter and everything inbetween. The zoom climb did not just "appear" - it was explicitly ordered through the PF's flight control commands, as was the THS. The THS didn't really become an issue until well into the stall regime, which - and let's not mince words here - it should be reasonable to expect that with the warnings they had that a crew should have been able to diagnose and either avoid or recover from. All they had to do was push forward on that stick.

Depends on your definition of "simple", really.

Put it this way - throughout the history of civil aviation and its technical advances, pilots have not needed to understand the principles of things like cams, tensile strength of metals, hydraulic flow management and the like to fly the aircraft of those eras - because all of those technologies required specialist knowledge to some extent, and as such were not actually that simple. Some pilots did go the extra mile in understanding, some continue to do so and some in this era have extended that understanding to the modern electronics and computer technology behind their aircraft.

The point I'm trying to make is that it's no different. Whether we're talking about tensile load on a cable, hydraulic fluid flow to actuators or electronic signals it's all the same thing.

Did you see the part of my post where I likened modern aircraft management systems to an electronic flight engineer? I think it's a useful concept to understand. I'm sure some will argue that it would be better to just bring back the flight engineer, to which I'll say this; I had the pleasure of visiting the Hiller Aviation Museum in California a little while ago, and had a walk around their exhibit of a B747-100 flight deck. Now for its time, the B747 was a technically advanced aircraft - though by the standards of today the systems were relatively basic in themselves. I stuck my head into the flight deck and what jumped out at me was the sheer number of dials, switches, controls etc. at the FE station - to say nothing of the humungous bank of CBs overhead. I have to admit that to the layman's eye, the amount of things that needed monitoring, checking, activating and deactivating looked to be pretty close to the limit of what one human being could be reasonably expected to manage. This is absolutely no slight on FEs - if anything, seeing that in front of me elevated my level of respect even further - it just looked incredibly daunting, and far from "simple". Now bear in mind that "under the hood", the systems on more modern aircraft - not just Brand A, but even the venerable B757 and 767, are massively more technically involved in many ways (not because of the technology as such, but purely because of the greater number of parameters involved), and you can see why managing those systems with computers had to happen.


Think about it for a second - why would you not want full thrust commanded with flaps extended and an engine out? Sudden asymmetric thrust during take off/climb-out or final approach/landing could really ruin your day!

@tdracer - Correct. Though I'd be inclined to be a bit less harsh on the Birgenair crew - the LHS ASI did "come alive" during the takeoff roll, and in that circumstance there was very little time to cross-check. By the book it was a major error, but nevertheless understandable. What was common to both, if I recall correctly, was that at various points both the overspeed warning and stall warning (stick-shaker) were active. Additionally, and I've said this in the past, the Birgenair Captain was an ex-Air Force pilot - no "child of the magenta" - and even he was flummoxed by the information he was being given.

bubbers44

We all know some pilots need automation and others can fly attitude and power using QRH. If the altimiter works, use it, if the attitude indicator works, use it, if automation works use it. Use what ever still works and any competent pilot will make it work. I wouldn't want to be on an aircraft with a pilot that had to have automation to fly his airplane.

Many here disagree with that but I have considered loss of all power in my B757 including battery power and with no eletrical power know I could navigate and land safely if I had visual reference to a horizon. Whiskey compass and clock with standby altimiter would navigate and standby airspeed and alternate gear and flaps would handle landing.

I even played around with the whiskey compass in the 757 heading southbound over Cuba just using the compass to keep wings level for fun and it works just like a J3 cub. With the lead error you will not bank if you hold a south heading. You don't even need an attitude indicator in the clouds with all dead electronics. I learned that as a student pilot in an Aeronca Champ with 3 hrs. Those aircraft had no battery so no automation and it worked just fine. Funny how some newer pilots depend on it but we never had it and didn't need it.

DozyWannabe

Bubs - with all due respect, and as vilas has said - what does automation have to do with what's being discussed at this point?

Airbus aircraft have not had a greater or more complex level of automation than their Boeing or MD counterparts for more than 30 years (almost 40 in fact). Airbus never pushed automation harder than any of their competitors either. The trajectory indicator line on the NAV display isn't even magenta on an Airbus!

Your 757 would still require some power supplied by the RAT to land as you describe, and RATs are fitted across the Airbus range too.

bubbers44

The 757 didn't have a RAT, the 767 did. The 757 could be flown just fine with no electrical power including battery. If my 757 had a RAT I am sure somebody would have told me.

DozyWannabe

Err... Looks like it has one to me...

File:757 ram air turbine.jpg - Wikimedia Commons

It'd be lunacy not to have one on an all-hydraulic (i.e no manual reversion) design like the 757.

bubbers44

My airline career started in 1979. We rarely used the autopilot for approaches, just for the boring enroute portion. Automation was optional. A major airline bought us and guess what, nothing changed, automation was optional except for certain category approaches. Now airlines are hiring pilots from pilot mills that can barely fly and teach them how to push the right buttons.

I know this is going to irritate a lot of people here but I wouldn't want to have this kid as my copilot before I retired. I want a solid qualified seasoned FO that knows how to fly. As a brand new 737 captain I got this kid that couldn't copy a clearance, couldn't fly, didn't know 24,000 ft meant FL 240 and our autopilot was broke. It was a charter to Minneapolis from LAS and I was single pilot both ways. A check Airman got him in as a favor to his neighbor and gave him all his training and check out.

Everybody else knew how to handfly and copy a clearance but he didn't. I don't have a lot of patience for pilots who don't bother to learn how to hand fly.

bubbers44

Kind of strange we had no procedure to use it and it was on our airplane without our knowledge. Maybe it is an option Airlines can buy. Thousands of hours on a 757 and nobody told me? Maybe it is an option our airline didn't buy. The 767 had it.

Wally Mk2

'bubbers' you mentioned in one of yr posts that if all 3 A/S's indicators go away in yr Boeing you use Att & Pwr from the QRH, well that's the same for a 'Bus' in fact any A/C, very basic airman-ship stuff there. This is the basic crux of why AF447 ultimately crashed.
I believe the real reason why these guys let a fully serviceable machine (other than the probes) take the lives of many was that they simply didn't believe what they were seeing in front of them & therefore any corrective decisions are ultimately overridden, their brains remember cannot act unless it's getting info either from stored memory (IE Knowledge/experience) or 'believable' info thru the eyes (the most powerful sense we have), the latter actually fooled them into believing the A/C could climb aggressively at that weight & at that Alt due a perceived over-speed initially hence the full back stick for the majority of the event.
They crashed simply 'cause they had no idea what to do, confusion reigned Capt included 'till too late.
Also 'bubbers' I gather that there is no external evidence of a RAT on the 757 like there is on an A320 for Eg as these closed doors form part of a pre-flight inspection.

vilas

bubbers44
Thousands of hours on a 757 and nobody told me?
No offence meant but if that is the case on aircraft you flew even if your airline didn't opt for it what chance is there that you would know or care to know anything about the Airbus. You don't fly Airbus, you don't know anything about Airbus, you don't care to know about Airbus but you want to comment about Airbus incidents. How correct is that?

DozyWannabe

I very much doubt the RAT would have been an optional fit on the B757. As I said before, as an all-hydraulic design with no mechanical reversion the RAT would have been required to keep the hydraulics functioning in the case of dual engine and APU failure (e.g. fuel starvation). Even if bubs was able to navigate minus batteries with his whisky compass and outside horizon reference, it wouldn't do him any good if the flight surfaces stopped working (which without the RAT supplying hydraulic power, is exactly what would happen)!

There's an old saying that I adhere to along the lines of "I may disagree with what you are saying, but I'll vigorously defend your right to say it". I don't think any of us have the right to suggest members shouldn't contribute, even if we feel they're misinformed or misguided.

tdracer

I don't recall off hand if the 757 has a RAT or not. But the fact that it's a all-hydraulic airplane doesn't mean a RAT is necessary. The 747 is all hydraulic, and prior to the -8 it never had a RAT - it wasn't needed. In the case of an all engine out event (and there have been a handful of 747 all-engine out events) there is sufficient hydraulic pressure provided by the windmilling engines to provide control of the aircraft.
Since the 747 all engine out events that I can recall had happy endings (volcanic ash encounters) the Boeing engineers apparently got it right.
The 747-8/8F did get a RAT - the combination of greater hydraulic requirements (due to the new wing) and engines that windmilled slower (big fan/small core) meant a RAT was needed.

DonH

For Bubbers' information, there are AD's referencing the B757-200 RAT from early 1988. Even as the original type certificate was issued in 1982, the B757 appears to have always had a RAT. The site for FAA TCDS's are available but do not prescribe system specifics.

DonH