Dash 8 hydraulics

[Oakape]

It seems a Q-Link Dash 8 returned to CBR on Wednesday night on a CBR-SYD sector, due to a rather large hydraulic leak from the area of the left engine. Hydraulic fluid streaming back over the nacelle & into the slipstream.

Captain announced that the ensuing landing on 35 at was completed with no flaps & no brakes & that the figures showed they had 500m to spare. He turned off onto the taxiway at the end at low speed & used the emergency brake to stop.

I assume that the thing has more than 1 hydraulic system, but was wondering that was in fact the case. It would seem that there is no alternate flap extension & no alternate brake system except for the emergency brakes. Would someone like to confirm that? Thanks.

[717tech]

The thing has two hydraulic systems.

With a failure of the left system, they still have emergency brakes (no anti skid) which can be used on landing. From memory there should be enough pressure in the accumulator for four full applications of the emergency brake.

[Di_Vosh]

Correct, two Hydraulic systems:

The Mnemonic goes B-FAIR LONGER

#1 System:
B - Brakes
F - Flaps
A - Anti Skid system
I - Inboard Roll Spoilers
R - #1 Rudder Actuators

L - Landing Gear
O- Outboard Roll Spoilers
N - Nose Wheel Steering
G - (no longer used)
E - Emergency Brake (park brake)
R - #2 Rudder Acutators

That was for the Classic. The Q400 is similar.

So yes, if you lose #1 system you only have the emergency brake (more likely three applications instead of four, done very carefully as there is no anti-skid) and you'll be landing with zero flap.

If you lose #2 system there is an alternate gear extension system that will get the gear down.

DIVOSH!

[maverick22]

To be technically correct a Q400 actually has 4 hydraulic systems. The number 1 and 2 systems, which are the main ones that power landing gear, flight controls etc. the number 3 is a back up if you lose the 1 and 2 systems. It is driven by a DC motor pump and purely operates the left and right elevators. The 4th system is for alternate landing gear extension.

The above scenario sounds like it was straight from the sim. Well done those men (and or women).:D

[Di_Vosh]

Erm.Yes.

Well done to the crew!

DIVOSH!

[HeSaidWhat]

Maybe it was the fault of 'the third oil line'. God I miss the old 'dog whistle'.

[Hugh Jarse]

*Cough, cough* Ailerons should be roll spoilers, as the ailerons are cable operated ;)

Just saying :8

I thought providing the #2 system was powered you had continuous hydraulic pressure to the emergency brakes. The 3 or 4 apps was only applicable in the case of loss of both hydraulic systems, leading to only stored accumulator pressure in the emergency brake? :)

It has been a few years......

[noclue]

If number 2 system was still operational, you would have unlimited emergency brake applications.

[HappyBandit]

Yes Hugh you are correct, infact I had this exact scenario as a rejected take off scenario not that long ago. So yes unlimited emergency brake application. You just need to be careful how you apply it.:)

[Di_Vosh]

Do'h!

How embarrassment...

DIVOSH!

[Oakape]

Thanks for the information. I understand there were a few nervous ones down the back, but they were happy to be back on the ground & impressed with the Captain's debrief. The job was was done well with a minimum of fuss.

[Mister Warning]

DV couldn't you revise the acronym to BFAIR LONER then?

[Going Nowhere]

Which is exactly the way it's taught MW

With the addition of E to both for the Elevator.

[Di_Vosh]

DV couldn't you revise the acronym to BFAIR LONER then?

IIRC, when I first learned it there was a "G" for "Ground spoilers".

But I made such a mess of my post here I thought I'd quit while I was behind. :ouch:

DIVOSH!

[MTBUR]

Awkward...

[Fuel-Off]

Divosh, DMc would have your ass in a sling next sim, for spouting incorrect knowledge for that! :}

Fuel-Off :ok:

[helimutt]

Just a quick question for those who may know, what oil is it likely that I saw dripping from the right hand landing gear area, out of the outboard side of the wheel well, and down onto the outboard tyre whilst parked on the tarmac. A number of people walking around the aircraft noticed it and walked away. Slightly uneasy about seeing the oil all over the tyre, and not contained in an aircraft system, I brought it to the attention of the stewardess, who then informed the Captain, who then went and had a quick look. It must have been okay as we took off shortly thereafter. On landing at destination I again saw more oil dripping. :eek: Normal on a Dash 8?

[geeup]

ARPs or ISO aircraft?
Both have reservoirs left & right.

[Toodogs]

There are engine oil reservoir breathers at the aft end of each nacelle. This area accumulates oil with ground running and it can make its way as far forward as do drip on the main landing gear (and pilots' shirts).

[helimutt]

Thank you. :)

[Random Manoeuvres]

JennyTal, why don't you actually contribute something to the conversation rather than taking cheap shots at di vosh who at least has an input. Remember, "Professional" pilots. :ok:

[AerocatS2A]

Yes cheap shots. If you have a personal problem with someone, deal with it privately. This forum isn't provided for you to go around making snide comments about forum members. I don't see where Di Vosh changed the subject at all, he added some pertinent information and got a small bit wrong, whoop de doo! (and he happily owned up to the mistake.)

[Tu.114]

Dripping oil is not that common, but not really unknown either around a DH8 nacelle.

First of all, there is a load of drain pipes, some clustered to form a big drain mast on the lower L/H side of each nacelle (coming from various sections of the engine, some direct and some via a overspill reservoir), and another smaller one protruding from the tailcone of the nacelle (taking the overflowing liquid in case the hydraulic overspill containers in the main gear bays are full). If something comes out of those, maintenance tends to ask two questions: which exact pipe it is and how many drops per minute (as this is often limiting) come out of it. Usually, it is just the container that needs emptying when a maintenance base is crossed the next time; in case of more drops per minute than allowed from some of the pipes, aircraft have been grounded as well already.

If the drops are not from these pipes, chances are that it is no oil at all, but deicing fluid that accumulated in a corner during the last leg(s). It is fairly common that drops are seen on the open main wheel doors and also fall on the wheels in winter even a few legs after the last deicing. This is not harmful to the wheels and this would also explain the nonchalant attitude to Your observation the crew displayed on Your flight.

[Josh Cox]

Jenny,

At least he put some meat in the game, the number of arm chair experts, such as yourself, that never actually contribute, at all, yet are critical of those that do, is disappointing.

If you are such an IR expert, get on the Council and set the world on fire. I bet you don't.

And before you ask, yes, I am a member of the "Di Vosh" fan club, the President in fact, Membership number: 0000001. :)