Well I can tell you about a brand new 7X that used to be based here that while on an overnight trip to a certain airport, the crew decided to use the parking brake for what ever reason (no chocks) on a slanted ramp...

During the night (less than 10 hours after shutdown) when the parking brake pressure finally released, the aircraft rolled backwards and left the ramp to end up in the muddy field where it sank... The pilots were woken up by airport authorities about the incident which was caught on the airport's security video system.

I know on the type I fly, the parking brake will not hold once the hydraulics are turned off and there is no time frame given by the manufacturer as to when they would release. The manufacturer requires you to have all three sets of wheels chocked when parking the aircraft for an extended stay.

Anyone that flies into ZBAA will noticed that all business aircrafts are tied down by the airport authorities and you have no say in this. However I have never seen other airports where we operate in and out of that have the proper in-ground mooring system that could be used for these types of aircrafts.

Lord Ashcroft is a major donor to the Conservative Party.
He was Vice-Chairman of the party.
In 2000 he agreed to giving up his (tax advantage) non-dom status in return for being made a Lord.
He has not kept his word and continues to avoid paying tax by claiming non-dom status whilst sitting in the Lords as a Conservative Peer.

The same type I was talking about;)

All very interesting, but what has this to do with the incident?

Does this info help to understand what and why it happened?

Nah. Just a bit of poetic justice.

Parking brake off might be FBO policy... but it's your problem.

Also, an arch-Brexiteer, who has used his influence for personal gain.

Not familiar with the Falcon, but doesn't the Emergency brake accumulator also hold the brakes when without hydraulic power? If thats not working without hydraulic, whats to say it will work in a hydraulic pressure failure situation. Anyway, an e mail to Dassault from the fleet manager should illicit a response on the time it should hold.

Apparently, not familiar with accumulators, either. Eventually, the brake, or any, accumulator bleeds down to the pre-charge of nitrogen and off go the brakes.


Gf

Nah Galaxy, my aircraft states 24hrs before loss of effect, hence the question about dassault having a stated figure.

A cut and paste from Aom "

The accumulator allows 6 complete emergency actuation or at least 24 hours of parking brake actuation."

As for not knowing what an accumulator does, well thats simple. It stores pressure, how the aircraft uses it is type specific.

On my aircraft the following applies...

The emergency/parking brake is controlled through a handle located on the left side of the control pedestal. This modulates the Emergency/Parking Brake Valve. When the Emergency/Parking Brake Valve is actuated, hydraulic pressure coming from a dedicated accumulator is equally applied to the four main landing gear brakes. Braking capacity is proportional to the handle displacement. A BRAKE ON indicating light illuminates to indicate that pressure is being applied to the wheel brakes. A locking device allows the handle to be held in the actuated position, for parking purposes.
The accumulator is supplied by hydraulic system 2. A caution message is displayed on the EICAS in case of accumulator hydraulic low pressure. After the message is displayed, if no leakage exists, at least one full emergency/parking brake application is available. If overpressure occurs due to overheating, a thermal relief valve allows hydraulic system communication with the return. A refilling connection is provided to allow pressurization of the accumulator.

Probably should throw a little abuse back at ya but I'm not that sort of guy.

Careful there GF, you appear to be stating a fairly common misconception of a hydraulic accumulator. It doesn't matter how much nitrogen pressure you have or haven't got in an accumulator, once the piston or sealing membrane (between nitrogen and Hyd fluid) has reached its stop the output hydraulic pressure drops to zero!

All I’m saying is pre-charge won’t hold the brakes. I don’t know your type, but 24 hours seems like a long time. Apologies, if offense was taken.

GF

Hey, absolutely no offence taken GF, and your point that any hydraulic pressure on the output of an accumulator will inevitably dissipate over time is absolutely correct.

My point being you can have a 2000psi Nitrogen pre-charge on an accumulator with zero psi on the Hyd side; you don't necessarily get a minimum Hyd pressure equivalent to the Nitrogen pre-charge.

Agreed, sir. I’ve had experienced pilots tell me that the pre-charge means the accumulator can hold the brakes indefinitely. Wrong.

GF

Embraer 145 135 legacy for your info Galaxy.
The point i was making was that the leakage from the pressurised hydraulic fluid could be from system leakage over time or point failure. If the manufacturers specified time is not being met, then that indicates system failure. We have had this with another accumulator powered system other than brakes.

I do think there was a little language issue in the responses that may have caused confusion. Tech talk and fast replies on the move.....

Either way Dassault should be pulled up to specify so further incident risk can be avoided.