hydraulic failure

[brs planespotter]

we here @brs had a 319 of the orange variety return too stand with hydraulic failure,what/how would the flightdeck control the situation if the a/c had just passed v1?bearing in mind our4 short runway and the gusting gales...........thanks..brs planespotter

[BOAC]

if the a/c had just passed v1?

- I think they would fly! Read up on what V1 is.

[brs planespotter]

apologies boac

that was miss spelt by me!obviously after v1 they r flying,but what would be going through there minds and be doing,many thanks

[411A]

... after v1 they r flying...

You might get a reasonable answer if 'text BS speak' was not used in your messages.
Until then...keep on trying.

[Rainboe]

Going through their minds would be simply getting airborne normally and climbing to a safe altitude before trying to do anything. Airliners are failsafe- hydraulic systems are independent of each other and don't all fail together. The aeroplane is still perfectly flyable. It is not a drama. Most experienced pilots have lost hydraulic systems. The 737 has 3 hydraulic systems and can lose them all and still be controllable. If you are cruising along and lose a hydraulic system, you don't even have to make a precautionary landing! Just continue to destination. So no drama at all.

Mate- please- I had to read that all over twice to get your meaning. You really do know the difference between here and hear, what they're and their and there mean, don't you? And why should capitals get left out? They have feelings too!

[BOAC]

So - if you could reply in normal English (as 411 has observed), what exactly was the question again? Above V1 a 'short runway'/'gusting winds' and 'Bristol' do not make any difference to the way it is done..

[simonchowder]

Im no techie but i believe this a/c has as rainboe states three totally independent hydraulic systems, and triple redundancy on the vital systems, so a failure in one system is no big deal, and would not have had the pilots frantically looking for a school/orphanage to avoid crashing into, sorry BRS a non event i would imagine

[tom775257]

Yes on the A319 you have triple hydraulics. If you lose all three while in the air you are dead.

On the A320 series, loosing one hydraulic system has no serious effect. Loosing two starts to increase the workload a lot, for example lose the green and yellow hydraulic system, you loose the ability to operate the flaps among many other things. Dual hydraulic failures lead to a fairly complicated procedure too...in the G+Y failure ECAM actions, dual hydraulic failure QRH, Slat/Flap jam QRH, landing distance calculations and manual gear extension QRH. High PNF workload!

[leewan]

Yes on the A319 you have triple hydraulics. If you lose all three while in the air you are dead.

If you mean lose hydraulic pressure in all 3 systems, then you still have the RAT to provide the pressure. There are also check valves to prevent excess loss of hydraulic fluid. Moreover, there at least 2 pumps for each hydaulic system. Losing a hydraulic system, as Rainboe states, is a non-event. But losing 2 or more is an event but still flyable albeit with some difficulties. I actually started a thread regarding this a few months ago.

High PNF workload!

It's exactly because of these scenarios that they are paid the big buck$. Most of the times, they are just system administrators.

[tom775257]

Leewan, depends on the failures, obviously many scenarios could happen. The fact is if you lose all three hydraulic systems completely on the A320 series, you are left only with differential thrust for control, then it would be up to the pilots to have a go at crashing in a 'controlled' manner I would think.

I was just pointing out unlike the B737 which can be flown without any hydraulic pressure (as per Rainboe above), the A320 has no flight controls functioning with no hydraulic systems functioning. Mechanical back-up on the bus is to do with complete flight control computer failures, any action on the trim wheel or rudder pedals would still be actuated using hydraulic pressure.

An interesting quirk on the A320 series is that the PTU (power transfer unit) that allows the green to pressurise the yellow system and vica versa can actually cause a dual hydraulic failure. An example would be you have a major failure in the green system, now the PTU is runnning flat out being driven by the yellow system trying to raise pressure in the green with no liquid to run against. Without fairly rapidly turning the PTU off manually, you could damage the PTU and overheat the yellow system. We had an aircrew notice about this exact scenario, basically saying if you loose green or yellow just after take off, don't take too long about doing the ECAM actions; in this rare case a simple single failure could cause a double failure without prompt flight crew actions.

Cheers.

[leewan]

Tom, it's quite true that you are on a wing and a prayer if you lose all available hydraulic systems. That applies to all commercial a/c flying now excluding the A380 and the B737.
But then again, it's a statistically remote event to lose all available hydraulics at once.
AFAIK, such a thing has only happened thrice in the past 40+ years. ( JAL 123, Sioux City DC-10 and the DHL A300)
In most cases , an aircraft only loses one hydraulic systems( a rare event itself) and the other systems take over. The pilot in most cases would divert to the nearest airport as a precautionary measure.
Guess the rarity of such a thing happening didn't warrant the manufacturers to built a hydraulically independent flight control system ?

[Rainboe]

Just to correct a misleading impression in the preceding post. From Part B (Procedures):

The QRH states "If only one hydraulic system remains, LAND AT
NEAREST SUITABLE AIRPORT'. The B737 has three hydraulic
systems "System A", "System B", and the "Standby System".
Boeing consider only one hydraulic system remains following:
Loss of both System A and System B; or
Loss of System A and the Standby System; or
Loss of System B and the Standby System

Loss of any one system would, I think in most circumstances, lead to the following: outbound- return to base (no point going if you will be stuck away). Inbound- continue to base. If on single multi leg trip- review most efficient maintenance option. Always review MEL.
The point is- loss of a single system in a 3 system aeroplane does not cause an emergency response. There are no specific diversion instructions relating to loss of a single system.

[Monsoon123]

Please tell me the reason to extend the landing gear at last on a 320 in case of g+y failure

[Tail-take-off]

The crew probably wouldn't even know that they had a single hydraulic failure at V1 because the ECAM caution is inhibited between 80kts and 1500'.

[mockingjay]

Rejecting the TO after V1 will likely end in tears, particularly if you're departing RWY27 at BRS. After V1 you'll still have control even with a two systems failed. You'll still have aileron and one roll spoiler. You'll have THS and elevator. Slats and flaps may be slow to restrict and extend although there's a good chance the takeoff config would have been maintained while the crew did their troubleshooting.

Without failures the aircraft is in normal law (all singing all dancing fancy Airbus mode) You'll extend the gear last as the aircraft will be in direct law (Cessna mode) once the gear is down. On loss of both hydraulics it'll be in alternate law (Cessna mode + a few stabilities to assist) and then direct law once gear is down. Leaving the gear until last saves pitch and trim changes, reducing workload on the pilot.

If you loose all three, not all is lost. Although not a flight law (as the side stick is out of use) if you lost all of your flight computers or all hydraulics and the RAT is unable to pressurise the blue system at all you'll be in Mechanical Backup. Not pretty (you have just your rudder, pitch trim and manual thrust), but it's an option.

[friendly flyer]

Not correct. If you lose all 3 hydraulic systems there is no mechanical back up on the A320. If you lose all 3 you are toast