BA 747 100Kts & stick shake?

[Sir Kitt Braker]

Lots of rumours around about a very recent BA go-round at LHR in a 744 resulting in a very low speed, stick shake and immediate crew suspension. Anyone confirm or deny? Everyone's being too tight-lipped about this - I am therefore very suspicious!

[Joyce Tick]

Yes Sir Kitt, heard the same today. A go-around in good weather due blocked runway is what I heard, with a stall or near stall soon after. Someone in authority refused to confirm or deny or this rumour - not a good sign!

[Pete Otube]

Crew probably stone cold sober with the new rules - enough to make anyone stall!

[bankrupt]

Those pesky withdrawal symptoms:E :E :E

[DanAir1-11]

100KIAS?????

Bu99er! I didn't think a 744 would still be flying at 100?

Is that legit? and if so, could 747Focal or any of the other Boeing chaps advise what she would be capable of at the scary end of the brown underpants scale.

Regards

[jtr]

Well the APPCH speed chart goes down to 180T, and the speed is 121kts. So stick shaker @ 100kts sounds right. More realistic with light wt and lo gas is landing wt of 220T, which is 134kts, so still plausible to have stick shaker around 100kts. My guess is that at stickshaker on a GA, not too many people are going to be focusing on precise speed tape reading.

[srjumbo]

Possibly with these 'monitored' approaches where they hand over control during the approach no one knew who had control. I'm not sure how the system works though.
Vref an landing is usually around 140kias. Had they gone around and pushed the TOGA button the autothrottle would have engaged which would give speed protection.
But for the grace of God there go a lot of us!

[Well thats Me]

srjumbo

I dont know the Jumbo but during a manual GA isnt it posible for the crew to pitch and lose speed before the engines can recover it - i know all the guidance ( a/p and f/d ) is speed related.

[ETOPS]

Minimum speed was 113kts.

[126.9]

Can't help but wander if this thread is not an internal meeting of reporters employed by The Sun..?

:}

[Phoenix_X]

srjumbo, the autothrottle will not give *any* speed protection, as it simply applies maximum (GO-AROUND) thrust. So pitch the aircraft up high enough, and it can do nothin' at all to protect the speed. An Airbus on the other hand.... *ducks* :}
Also, no matter what you think of the monitored approach, crews have been trained well enough in performing these approaches, that they know who's in control at what stage, don't worry.

Well that's me, yes, it's also possible to pitch the aircraft up too much before the engines have spooled up.

Then again, it probably is a Sun reporter meeting :E

[LOMCEVAK]

I assume that the stick shaker is triggered by a vane that senses angle of attack. Therefore, during a go-around with a high nose up pitch rate the speed will be higher when the critical AoA is reached than it would be during a wings level slow down. In other words, if the stick shaker would be triggered at, say, 100 KIAS in straight and level flight, it would trigger at a higher speed during a dynamic go-around. And the more aggressive the nose-up rotation, the higher the speed.

Perhaps it should be considered that if the aircraft was forced into a very late go-around due to, say, a runway incursion, a very rapid rotation which triggered the stick shaker may actually have prevented an accident! I have no facts, but there are two sides to any coin.

[TINBASHER99]

Just for some info, the stall warning system (Stick shaker), looks at Aircraft Speed, Angle of attack and Flap position and also engine speed and flight status. All these parameters are monitored by a stall warning computer, if the correct combination is monitored, then the stick shaker will operate. These could be, low airspeed or high angle of attack with incorrect flap setting.
The point at which the warning occurs is also influenced by engine speed, airspeed, and any asymmetry between leading edge and trailing edge flaps.
The AOA sensor monitors 'relative' airflow, so with a high nos attitude at slower speeds the AOA will be high, but at higher speeds such as climbout it will be less. It is just like a weather vane.
Hope this helps.

[Devils Advocate]

What a lot of cobblers, i.e. non-news !

You can have the stick shaker going off during all manner of manouvers wherein having the stick shaker going off indicates that you are approaching the stall - not that you have stalled ! :mad:

E.g. Who here remembers the Continental B747 - 'twas in the late 1980's - which took off from LGW and was ( if my memory serves me right ) bound for MIA i.e. it was very heavy, but wherien it then had one engine fail and another suffered a partial failure, following which it just about missed some hills to the west of Gatwick ( Rushy Hill ? ), i.e. litterally by only a few feet - and pretty much the whole thing ( well certainly the first few minutes ) was flown with the stick shaker rattling away - after which they landed back at LGW somewhile later ( having dumped mucho fuel over Sussex and the English Channel ); the flight crew did an heroic job !

[Cakov]

And if the autothrottle was not engaged... or was disconnected? Would you get go around thrust?

[Capt Fathom]

100 knots is OK, as long as you're pushing, but not pulling! :suspect:

[carbheatcold]

Devil's Advocate,

I remember the Continental 747 incident and it was Russ Hill that it just missed. They were cleaning fuel off everything in the area for days afterwards.

If for some reason it was a late go around call which required a rather prompt pull on the column could you end up with a false stick shaker warning as the AoA temporarily read excessively high especially if the speed was slow, maybe close to Vref?

chc

[alf5071h]

There, there, don’t get too excited … sounds like a commercial for insurance, but that is exactly what a stick shaker system is. It is an alert to an unusual condition; more forceful than a call from the NFP, like a friendly poke in the arm giving the handing pilot additional awareness or, if necessary, a wakeup call.

As described earlier most SS systems alert at approx 1.1Vs, but with even earlier alerts for applied load factor (g) and high pitch rate, the latter features are available from alpha and alpha rate. Depending on aircraft type and SS system, the SS alert may be over sensitive to certain turbulence conditions, gusts, or even sideslip. Thus, providing recovery action is initiated there isn’t very much to get overexcited about, you still have 10% of stall speed as a margin.

We must wait for the details of this event, but bearing in mind that the certification and operational requirements of the aircraft require maneuvering close to the boundaries of alerting systems we should not be surprised if occasionally the limit is encountered. A max rate go-around could generate 1.25g, although most GAs are much less. This g level equates to an increase in the stall speed and corresponding SS speed to values not far from the normal GA speed Vref (1.3Vs) e.g for 100kt Vs x SQR 1.25g =111 kts. For a GPWS pull up crews should be taught to aim for 1.3 g, similar for ACAS until the maneuver is established. For a Windshear encounter crews are taught to fly ‘at’ but to respect the stick shake speed i.e. just short of an alert.

It would be disappointing for the industry if this crew were suspended for what appears to be a benign event; crews have enough stresses without the addition of such action. I detect an unhealthy trend in the industry where managers suspend pilots for the most minor of events (even good GAs); possible this is due to the continuing good safety record and there are fewer serious events to investigate. However this management attitude does little to maintain an open reporting and ‘just’ safety culture, nor does it encourage crews to fly near to limiting speeds when demanded by procedure or warranted by crew judgment.
Let us wait and see what actually happened during the GA.

[411A]

Stick shaker...well, that's what it's there for, is it not?
To alert the crew of a too low speed.

OTOH, did have a stick pusher malfunction in an HFB320 some years ago, just after takeoff at about 200agl.
Tried to bury the column in the instrument panel....now that will get your attention.:ooh: :yuk:

[thegirth]

Heard the handling pilot screwed up taking out A/THR at touchdown and hit TOGA button ONCE instead. He was trying to land, a/c wanted to fly (just). Took a while before crew realised quite what was happening. Low slow fly by and close to losing the aircraft. Subsequent landing was non-event.

That's all I will say.

[safetypee]

thegirth, from the scenario that you surmise I recall similar circumstances that resulted in a 747 leaving the end of the runway into water minus nose gear, etc.
This report is in French - (1.3mb) Pictures on the last page.
Air France Tahiti 13 Sept 93 (http://www.bea-fr.org/docspa/1993/f-ta930913/pdf/f-ta930913.pdf)

[Shore Guy]

Anyone know how to get this report in English?

[Ricky Butcher]

Seems girths report doesn't add up. Hitting the TOGA buttons once would give you engine power for a 2000 fpm climb rate. Attempting to land the aircraft with that power setting is going to give you an overspeed of something very rapidly. A low flyby maybe, but certainly not a slow one! The 'low flyby' scenario doesn't seem to tie in with the crew busting the 2000' level-off on the 27L go-around either. FYI, I am reliably informed the stick shaker did NOT activate during the event. From the information I can gather it seems this was a poorly handled go-around in which they allowed the speed to decay a bit too far, but the aircraft was above 2000' and had a very high power setting on four serviceable engines. Hardly calamity stuff.

[sevenforeseven]

A340/A330 series and we would not be reading this!!!!!

[Ricky Butcher]

I love alpha-floor!:ok:

[126.9]

Good to see The Sun reporters are still busy on this one!

:}

[BusyB]

Sevenfourseven,
No, we'd be reading about the 340 w/sh GA in HKG that looked up at the breakwater!!

[Dan Winterland]

Alpha floor protection probably saved that aircraft. Not sure they would have been so lucky in a Boeing.

[Doors to Automatic]

Devils Advocate/Carbheatcold

I remember the CO incident too - I think it happened around Jan 1988 if memory serves me correctly. The incident was I think due to a compressor stall in one of the engines due to a departure in a strong crosswind.

Aparently the aircraft cleared Russ Hill at a height of around 50ft and then disappeared behind it. The controllers at LGW actually sounded the crash alarm before seeing the aircraft re-appear.

For the first 5 minutes of flight the airspeed fluctuated between V1 and Vr and it took 30 minutes to reach 1500ft.

The aircraft landed back at LGW around one hour later without incident.

[sevenforeseven]

That was my point. Thankyou Dan.

[aiming point]

Highlights yet again that a Go-Around is a dynamic manoeuvre with many inherent risks.
Rarely practised and seldom flown for real, things may not always go as they should.
Hundreds of people have died in crashes over the years and there have been many serious incidents as a result of the "Boring, ho-hum" go around that many supposed "experts" on this sight like to peddle.
In this age of declining pilot handling skills, in part attributable to the ever increasing reliance on automation ( made mandatory by many Flt. Ops. departments), one should not underestimate the potential pitfalls of this seemingly innocuous procedure, imho.

[lomapaseo]

I recall the Continental 747 out of LGW but I have been unable to find any mention of it in either AAIB or NTSB reports to confim the stories about the stick shaker going off for 5 mins with speeds between V1 and Vr nor spending 30 mins below 1500 ft.

I believe that the crew were criticized for overpitching the aircraft following a compressor stall, not associated with strong crosswinds (after all they were clearly airborne when the stall occured).

There is a video of the event taken by a passenger available on www.fromtheflightdeck.com.

additions/corrections/discusions welcome

[BusyB]

Dan,

I don't think that incident would have happened in a Boeing (I've read the ASR).

[4dogs]

aiming point,

My team get to do a minimum of 4 go-round/missed approaches every proficiency check cycle - whether they want to or not. When you say "rarely practised and seldom flown", to what sort of training and checking environment do you refer?

Stay Alive (and practising to do so!)

[Del Prado]

the link to the gatwick continental incident is ;

http://fromtheflightdeck.com/assorted/co747.WMV

[XL5]

Speedbird aren't the only ones getting stick shakers on go- rounds of late.... I'm not referring to the 757 at Oslo. It used to be simple. Push the throttles to the firewall and quickly pull them back a bit as you pitch up to 10 degrees. Simply magic, a sensible power setting with a sensible climb rate giving an accelerating climb speed. Once you were safely on your way the engineer (remember him?) trimmed the power as the PNF incrementally sucked up the flaps and gear.

Now of course it's been made even easier for us; just push a button. Trouble is that what happens next isn't that sensible anymore. High pitch attitudes with low climb-out speed giving excessive closure rates to a low altitude level off would seem to be the norm. When it goes right it feels wrong and when it goes wrong it feels wrong . It always feels wrong but with the FMAs changing faster than the tumblers on a Las Vegas slot machine it's impossible to assimilate the rapidly changing situation and get back into the loop. Too much stupid automation.

[alf5071h]

I agree with aiming point, but unfortunately he missed the main point about the risks of a go around. Although a go around is dynamic, similar to take off and landing, there are few risks associated with the actual maneuver. The problems as he states, and thus risks, are with the lack of practice and that GAs are seldom flown for real.

If declining skills and over focus on automatic flight are at the root of the problem (and I would not contradict the point), then perhaps the flight ops departments (including the regulators) should reconsider the risks of a go around. Not that this should necessarily result in more training or checking, but that the risk assumptions and/or the operational procedures for GAs, should be revised; thus more hand flying could be beneficial.

If the incident is as described by thegirth and it also relates to the accident in Tahiti, then 747 operators should be far more concerned about the possibility of a common operating error with the auto-thrust system, which could lead to another incident. Furthermore, if there is a system operating weakness (selecting TOGA instead of Disc), then there may have been many previous near-miss events; how many of these have been reported and/or investigated?

[Airbubba]

>>Highlights yet again that a Go-Around is a dynamic manoeuvre with many inherent risks. Rarely practised and seldom flown for real, things may not always go as they should.<<

I'll sure go along with that assessment.

Some of the Boeings will give you very high pitch commands if you try to be smooth with the initial pullup at light weights. The command bars keep floating impatiently up to 30 degrees or so just as the throttles trim for the 2000 fpm climb. If you follow the bars all the way up and don't drop the nose fast enough to recover, you will decelerate rapidly. The command bars settle down after a few seconds but they can sure lead you astray on the initial pull.

As a training captain said "It doesn't do that in the sim..."

The Airbus twins go to full TOGA and have a more aggressive power application and pitch change than the Boeings in my experience. The Gulf Air A-320 crash in Bahrain was perhaps caused by somatogravic disorientation due to the rapid pitch change on the second go around. The plane didn't stall, instead it was flown manually back down into the water.

>>When it goes right it feels wrong and when it goes wrong it feels wrong . It always feels wrong but with the FMAs changing faster than the tumblers on a Las Vegas slot machine it's impossible to assimilate the rapidly changing situation and get back into the loop.<<

>>It used to be simple. Push the throttles to the firewall and quickly pull them back a bit as you pitch up to 10 degrees. Simply magic, a sensible power setting with a sensible climb rate giving an accelerating climb speed.<<

Yep, the emphasis in training is more trying to figure out the multiple mode changes and why inadvertant altitude capture occurred than designing simple procedures that consistently give the desired result. 100 ft AGL is a poor place for a systems exam in my opinion.

[Dan Winterland]

BusyB,

Perhaps, a Boeing may not have got into that situation - part of the problem was the crew's use of the automatics. However, once they got there, the situation was such that if it had happened in a Boeing, they may not have survived.

I base this statement on the fact that I was working for that company at the time, but on the 744 - not the 343. Just after the report was published, I completed a sim profile where we practiced that very scenario several times based on the perceived strength of the windshear that was encountered. Every time we hit the water despite having far more power than the 343. Scary stuff!

Having spoken to one of the crew, it seems they relied on Alpha floor - it worked for them.

[BusyB]

Dan,

Yes it was the use of the automatics that caught my eye. I certainly wouldn't have wanted to fly through that!

[CrashDive]

aiming point - at Astraeus we always brief the go-around before every approach and by this I mean that we concentrate as much ( or even more so ) on who says what, who presses what, who moves what, who does what, what GA thrust is required, etc, as we do on what the approach plate has to say about the latteral and vertical navigation aspects of the GA - and wherein, as you correctly say, it's something we don't often get to do for real and so careful review of the actuall stick and rudder bits go a long way towards helping to keep it safe.

Nb. This year alone I've presonally done two go-arounds, once due a GPWS "Terrrain pull-up" at Taba / HETB ( caused by an error in the approach procedure - since revised ) the other was as a result of not being able to see any approach lights at the MDA at Innsbruck / LOWI ( due snow storm ) - and I'm still here to type about it.

[Ramrise]

Evening gents,

there has been reference to an incident involving an a340 and Windshear I think it is. Can someone elaborate or can I read about it somewhere. It sounds as if it was very, very exciting, to say the least.

thanks,

[LOMCEVAK]

A company that I flew for had 2 different engine fits on their fleet of 747-200s. The simulator had the lower powered PW engines, and the OEI go-arounds practised during LPC/OPC were inevitably at max landing weight. Therefore, the performance was OK and the rates of climb and acceleration during flap retraction easily manageable. The first one that I flew for real (due to no visual cues at CATI DA) was in a more powerful RR engined aircraft, AEO, at light weight . The excess power was impressive, and a non-standard power reduction was needed during flap retraction to keep the speed under control in the SOP profile! No problems, as our operations involved a lot of hand flying due to the older generation of the aircraft. However, I always briefed this excess power aspect in subsequent arrival briefs.

I was involved in 3 GAs in 2 years ( 2 as PF, 1 as PNF), 2 for weather, 1 for a blocked runway, and although the workload was high the task was philosophically similar to take-off procedures and not a problem. It is interesting to consider the problems and scope for errors in automated GAs in automated aircraft vs manual GAs in manual aircraft. Comments from pilots with experience of both greatly appreciated.

[josephshankes]

aiming point

My thoughts entirely.

Just been told the other day by my "airline" that stick and rudder skills, (by that I think they meant basic flying skills), was well down on the list of priorities in today’s aviation/airline environment. Hand flying practice is also discouraged at all costs.

With that attitude, we are going to hear a lot more of incidences like this. If indeed that was the cause of this incident. It will get a lot worse, believe me and it worries the hell out of me.

My opinion is when current and familiar with manual flying skills, for that a/c, then when the automatics let you down for whatever reason, one is not afraid to go back to basics. ie fly the damn thing yourself.

[DouglasDigby]

Ramrise, can't find any report, but attended a company briefing where the A340 "windshear" incident was most comprehensively reviewed. Managed to trawl up some of the information, but please bear in mind that this is by no means categoric or the entire story!

They had a descent at 2000 feet/min over the sea – with a very low RA height. It was the second approach (the first had resulted in 2 windshear warnings, with subsequent go-around). Through a combination of circumstances (Terminal Doppler Weather Radar going down – it didn’t like the 75 knots of wind, local anemometers that wouldn’t report winds above 30 knots – a computer “fudge” due to geographical siting locations, and runway change), the crew (no fault of their own) ended up in worse circumstances than on their first approach. Most importantly, all weather warnings on the ATIS and from ATC controllers referred to “microburst;” this flavoured the crew expectations towards convective TS activity, whereas the actual conditions were severe windshear. There are numerous other facets that I can't quote or cannot remember!! However, the very positive aspect was that the software-related “protection” features of the A340 almost certainly saved the day. Similar conditions were programmed into B747 simulator, a ditching every time! IIRC, major changes for wind reporting/calculations came into effect at CLK shortly afterwards (don't go there with current company!).

Anyway, back to the thread - if terrain isn't an issue, why the heck is full TOGA power needed?? Many go-around altitudes will be reached in seconds if carrying out a "missed" from DA, light aircraft + full power = ROC like a rocket! Frightens the punters down the back too!!

[Sir Kitt Braker]

...getting back to my original rumour, I'm not too concerned about the stick shaker but I am about the 100Kts. That's close to losing the airframe and its contents altogether- on a go-round..

[Final 3 Greens]

Dumb question from a PPL, with a few sim hours.

If the airframe was close to being lost, wouldn't the stick pusher have operated?

[Hotel Mode]

Jumbo doesnt have one, only required for aircraft that can "super stall" normally T tail. Ie the 146 and ATR's both have them.

[Final 3 Greens]

Thanks, sim time was on a 'T' tail.

[Hotel Mode]

Thats alright suprised me when i did the course.

[overstress]

Just a thought - stalling speed is 'g' dependent so if you are bunting your brains out and you have enough altitude, there will be no buffet, even on a Jumbo at 113kts!!

(eg the 'vomit comet' used to train NASA astronauts and in the filming of Apollo 13 etc)

[Underdog]

[Ignition Override]

Seven four seven: so no problems were experienced while using the A-330/340 automation? Must be nice in theory, although I recall a few major problems years ago with very similar automation in A-320s; Habsheim, Alsace, India, Warsaw (hydroplaning with superior automation-the Luft. FO died)......and the tragedy at Toulouse with an empty 330 flown by factory pilots, bringing the two doomed Italian pilots on the jumpseats into eternity. Maybe such theory is, after all, not so superior as to allow any pilot to comfortably "rest on his/her laurels"?

Go-around proficiency: how often do YOU airline/corporate/mil. pilots fly a go-around, other than once or twice a year in a simulator, or a few pilots in their own small private planes?

I can not speak for any others, but after no practice for ten or eleven months, it can be a fairly intense situation, especially with no warning.:O

[320DRIVER]

As with a chance of a high speed RTO with every take-off, we must consider the low GA option on every approach.

[BEagle]

How often did we practise go-arounds on the RAF VC10? Several times per training sortie. 3-engined and 2-engined go-arounds also flown under the supervision of FIs. Not difficult, hardest part was levelling off after the go-around; 96% on all 4, accelerate and climb at 190 KIAS, retract flaps/slats at 1500 ft then manage the level off at 2500 ft to be stable at 210 KIAS - all whilst flaps/slats were moving. The manoeuvre wasn't dangerous, just required regular practice and sound manual flying skills....

Go-arounds are extremely rare in the civil world. Is getting behind the drag curve ar$eing about with an over-automated aircraft running away from you very likely to happen given the very low opportunity for practice nowadays? I would be very worried indeed to think that a crew could get so close to the edge of disaster attempting something as very basic as a low go-around.

[jtr]

Several times per training sortie.

A lot of us have never had the benefit of being in a government sponsored aero club, thus the expression "training sortie" doesn't come into our vocabulary.

[alf5071h]

There are hazards in using any automation irrespective of aircraft type, particularly if it is misused or the circumstances are unfamiliar. Whichever point of view is taken then either the design is deficient, the interpretation of its function or training is incorrect, or the operator just made a mistake; all of these are down to one human or another – designer …>>… operator. A solution to some of these problems is to renew familiarity with the equipment and its operation i.e. practice GAs.

Furthermore I would argue for this training to be done in the aircraft. There have been several incidents recently where crews have suffered from somatogravic illusion – false sense of attitude due to acceleration. Although simulators mimic attitude reasonable accurately, some acceleration cues are poor. Thus in a modern twin jet with high thrust to wt during a GA at the end of a sector, it may be the first time that a crew has experienced the conditions conducive to somatogravic illusion.

There is good presentation on the 757 Oslo incident that involved such an illusion; extracts are here:- A GA Goes Bad.pdf (http://uk.geocities.com/[email protected]/alf5071h.htm).
It is interesting to note some of the other findings of the investigation; the PF was ‘automation dependent’, he had a slow instrument scan, concentrated on a single cue, and was out of practice for hand flying skills. Sounds like a training / checking issue to me.

Earlier posts referred to a Windshear GA; I do not have a link for the specific event, but there is a very good write up on an incident where the captain correctly flew a Windshear GA maneuver, at or near stick shake, and even after ‘clipping the trees all crew and pax survived:- An Accident of Windshear. (http://www.fly-safely.org/story_pf.asp?id=32)

[BEagle]

When simulators can provide real 'g' (not just pitch, roll, yaw and heave), the go-around can be correctly simulated. Until then, only practice in the real ac will suffice.

jtr - by 'government sponsored aero club', do you mean ba?

Are you a pilot or an apartment salesman?

[jtr]

No Beagle, by (tongue in cheek) govt sponsored aero club, I mean the armed forces Didn't hit a nerve did I???:D

And since you asked, I do have an apartment for sale, so please let me know.

Now I am not sure which airline you work for, but certainly with the mob that pay me, if I decided to do a "practice g/a", there would be a few raised eyebrows.

[BEagle]

Did you really? Gosh, well silly me - I'd never have guessed... :rolleyes:

I don't work for an airline, although I do have a JAR ATPL(A). It simply doesn't appeal to me...... 10 or 20 years ago, perhaps. But in today's world - not b£oody likely!

Back to the thread - if the reports of this low go-around are true, then perhaps it's a health warning to all the bean counters who have conspired to erode manual flying skills and decision making. With luck it'll at least be a nail in the coffin of the of the appalling MPL idea!

[jtr]

Yeah, got it, now about this apartment...:}