Dash 8 hydraulics
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Dash 8 hydraulics
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.
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.
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.
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.
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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!
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!
Last edited by Di_Vosh; 13th Mar 2015 at 21:24. Reason: Thanks Hugh
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).
The above scenario sounds like it was straight from the sim. Well done those men (and or women).
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*Cough, cough* Ailerons should be roll spoilers, as the ailerons are cable operated 
Just saying
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......
Just saying
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......
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.
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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.
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DV couldn't you revise the acronym to BFAIR LONER then?
But I made such a mess of my post here I thought I'd quit while I was behind.
DIVOSH!
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. 
Normal on a Dash 8?
Normal on a Dash 8?
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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).