airbus dead stick landing

[Steepturn]

Regarding the A330 that made an emergency landing, I am curious to know how the flight controls on the Airbus continue to provide command to the flight surfaces with no power; is this provided from the apu? Would the pilot be able to flare before landing? Would Boeing aircraft require power as well, or is there a physical backup in the linkage? I am not trying to start a flame war re Airbus/Boeing I am genuinely interested in how this works. Can anyone recommend a website or book that explains this? Thanks.

[widgeon]

Ram Air Turbine ( Rat ) which provides emergency electrical power and limited hydraulic power.
This is located near tail on airbus and just below the avionics bay on the Bombardier RJ series.
Efectiveness decreases with airspeed I would imagine.

[A and C]

The above post got it in one airflow across the RAT is critical so much so that the A320 sheds part of the ESS bus as the gear goes down and the nose gear disturbs the airflow across the RAT despite the fact that it is mounted off center and only just fwd of the main gear.

[ 29 August 2001: Message edited by: A and C ]

[Oilhead]

319 does not have the same RAT & gear combo limitations that impede the 230 in Emergency Electrical Config. I know nothing about the 330 RAT, but would imagine for it to pass ETOPS muster there might be an HMG (Hydraulic Motor Generator) too - like the 767's have - anyone tell me?

I think these guys at Air Transaat will get the ALPA Airmanship award next year barring another more deserving event in the meantime. Bloody good show blokes.

[planecrazi]

On the A340, it is possible to fly it with limited manual control via rudder and trim wheel which flies the THS, trimmable horizontal stabiliser. The RAT drives the green system hydraulic pump which powers the emergency generator at the same time. Failing that as a last resort, you would down to rudder and THS.

[measto]

In the Airbus A330, the RAT is located on the right wing (4th flap track fairing). The RAT powers the emergency generator via the Green hydarulic system. However when powered by the RAT, the emergency generator is inhibited when the slats are extended. Then the flight computers PRIM 1, SEC 1 and SEC 2 will be powered by the batteries!

[McGinty]

On the 330, will the RAT power the flight data recorders, or is this another case (like SwissAir 111) where the last phase of flight will not be recorded, this time because of loss of all engine power?

When the emergency generator stops because of the flaps being extended (pointed out by measto above), would that then stop the flight data recorders, assuming that they can continue to operate under RAT power alone?

I have a sneaking suspicion that the black boxes will contain no data about the deadstick landing.

[boofhead]

Jet transports with conventional controls (Boeing et al) will retain almost normal flight controls so long as an engine is idling or windmilling and hydraulics are not damaged. They do not need electrical power/RAT for this.

[go with the flow]

why doesn't the power come from the APU. One wouldn't imagine that this doesn't have any isolated fuel supply, would one?

seriously though, I know a RATs useful after going through volcanic dust, but if the APU doesn't have a dedicated fuel source this is a design flaw that should arguably be fixed. After all it needs SFA to run.

[Old Aero Guy]

If all engines quit in flight, control is maintained on Boeing jet transport aircraft in the following manner:

707/720 - Elevators and ailerons are manually operated via tabs, same as when all engines were working.

727/737 (All models) - Elevators and ailerons have tabs for manual reversion.

747 - Windmilling engines power all four hydraulic systems for all control surfaces, but at reduced rate.

757/767 - Ram Air Turbine (RAT) located in wing body fairing deploys and drives Center hydraulic system. Windmilling engines can provide some pressure to the Left and Right hyd. systems but landing flare capability does not depend on it.

777 - Same as 757/767 except RAT includes an electrical generator to keep the fly-by-wire flight control system operating.

[measto]

Answering McGinty's question, the digital flight data recorder (DFDR) is powered by AC BUS 1 in the A330-200. Hence without engine driven generators or the APU it is inoperative! The CVR can be powerd by the emergency generator but NOT when it is driven by the RAT!

[Steepturn]

Thank you for your replies, they were quite informative.

[Pengineer]

I could be wrong but....
I thought the Cripple seven had a schitload of batteries which powered certain flt controls in the unlikely event... etc etc.

[flufdriver]

I would really be interested to find out what the rate of descend might be in a total engine flameout situation. During my original training with Boeing on the 73-4, we used to practise dual engine flameouts in the SIM,(it was shortly after this had happened to TACA, when they put one in a Rice field in Louisiana) Unfortunately, I never had enough time to look at the rate of descend during those sessions, as we were rather occupied with the drill of relighting before meeting terra firma, which needless to say, always worked out.

Anybody have the answer to this?

[Max Revs]

I remember doing those dead stick scenarios in the 734 sim. The R.O.D. was 2000fpm in a straight line and 3000fpm in a rate one turn.To do a 360 took up 6000 ft and once round a racetrack pattern was 10000ft. Good fun in the sim, but I wouldn't want to do it for real ! :eek:

[Human Factor]

It is possible to fly an ILS and land a Scarebus (A320 series) in the manual backup mode, ie. rudder pedals and elevator trim only. Done it in the sim*. Hard work but reassuring, although for real it probably helps if you're Chuck Yeager.

* both engines were ticking over perfectly well.

[ 01 September 2001: Message edited by: airforcenone ]

[kippermate]

Regardless of the technical issues, I think that we should all take our hats off to the professional crew who performed outstandingly. I would not like to have been in their shoes, regardless of how many times I had done it in the sim! :)

[Roadtrip]

You should always use your superior technical knowledge and judgement to prevent you from having to use your superior flying skill. It's sounding more and more like an obvious single switch throw would have prevented a would-be simple SE landing scenario from tuning into a near tragedy.

The Air Transat episode is beginning to smell very badly. It'll be interesting to see what the real facts are.

[ 02 September 2001: Message edited by: Roadtrip ]

[Plastic Bug]

Roadtrip got it right. This is a situation where someone (unfortunately) snatched defeat from the jaws of victory.

It really boils down to complacency derived from some really reliable airplanes and the "fact" that this stuff never happens to me.

To Mr. Yeager: If you are who you say you are, Greetings and Salutations, I am Admiral Horatio Hornblower.

To the guys who wonder how an engineless A330 can still maintain flight controls, well, engines are engines. The rule of thumb is: if you can maintain 7% N2, you'll get hydraulic pressure from the pumps. It won't be great, but it will be there. As long as you don't try aerobatics, you will survive.

If you pull the fire handle, all bets are off.

On the bus, switching the fuel lever to off closes the LP valve, which kills the engine and shuts the familiar (fuel) firewall shutoff valve.

It's the same thing.

LP Valve = Firewall Shutoff valve.

If you pull the fire handle, the engine will be isolated, oh yeah, but you lose the hydraulics and pneumatics on that engine as well.

If you just shut the dang thing down, the engine fuel is cut off at the firewall, but you still have capability to get hydraulic power from the engine (no, bleed is gone).

It's a fine line. Put it this way: On the Bus: If you are not on fire, don't pull the fire handle.

My babbling 2 cents.

PB

[Max Angle]

Sorry if everybody has seen it but an article on the Air Transat 330 can be seen at:
http://www.globeandmail.com/servlet/ArticleNews/relatedstories/gam/20010830/UTRANN

Interesting point about pushing the fire handle or not when an engine fails. We used to be told to stop at the master switch for a no damage failure but now the trainers seems to be saying push the fire p/b even for a run down.

[stagger]

McGinty's "sneaking suspicion" was correct. CBC have just revealed that the DFDR contains no information about the deadstick landing.