Robin HR200 fuel cut-off

[atceng]

Robin HR200
Can anyone debunk the report that if you manage to prise up the fuel cut-off cover and pull the knob the fuel will be stopped and flow cannot be restarted in flight,but only when reset on the ground by an engineer ?
If this is true I'm going to wonder glue the cover. And wire it,and sellotape it Looks like it had a previous career in a B52.

By the way compared to my usual steed this is so like my old Volvo at the top of climb I had a geriatric moment, stabbed the rudder and tried to engage overdrive with the transmit button.:)

atceng

[A_Pommie]

You can restart fuel flow by pushing the knob back in. My mate found this out when he pulled the wrong knob. The guard cover was missing at the time.
If you're not totally sure try it on the ground to see what happens.

[atceng]

A Pommie

Thanks for your definitive reply. I couldn't believe that a manufacturer would install such a deadly one way street.
Now for the hard bit,how do I tell the much respected but volatile FI and persuade him to try it,even on the ground,as in his present mindset we'll need to get an engineer from 40 miles away if I pull the dreaded knob ?
I could promise to forego my lesson and pick up the engineer at my cost if we're wrong.
I'd better not have the slightest hesitation or omission in performing his 'flowline PFL check ' in future.
Do you think the myth was started after someone did a FL when they failed to detect and correct the problem in their pre FL checks, mags, fuel pump, carb heat, tank selector/cutoff etc.

atceng

[Ex Oggie]

:= There is a big caveot on this. If there is any resistance at all in the cable, it will not push fully home, just flex against the force of you trying to push it in. I would advise against trying it if you dont have an engineer to hand. Your choice, but I speak from experience.

By all means try it with an engineer around, its important you know how to operate it in an emergency, especially fiddling with the guard. It should be periodically operated in any case, to ensure servicability.

Cheers XO

[camlobe]

atceng, and any other operators of this aircraft, please take heed to the advice given. For those doubters, and any interested parties, please keep reading.

Back in the mid-90's, we were 'fortunate' enough to receive two brand new HR200-120B aircraft, one being the ex-demenstrator, G-BWFG. For the next two years, I was in constant, almost weekly, contact with the factory at Dijon-Darois regarding numerous issues, predominantly design issues. I even attended the factory and spoke to the Chief Engineer and the company Test Pilot (former ETPS attendee). Both were excuding non-stop gallic charm and suspicion (mai oui monsuier, but why don't you love our product). Through phone, fax and direct contact, the one issue I continually raised regarded the fuel cut-off.

You see, in those days, there was no guard cover over the fuel cut-off pull-knob, just a short piece of tell-tale wire. And, of course, it was in very close proximity to the carb heat knob.

Well, we found a major safety issue with this system when we carried out the first service after receiving these aircraft.

Pull the fuel cut-off to prevent draining the fuel tank while we dropped and inspected the gascolator. All OK, so reassemble the gascolator, and push the fuel cut-off knob back in and lock wire.

Head up the lower belly panel to have a look at everything...

The fuel cut-off valve was still off.

The bowden-type cable wasn't strong enough to push the valve back open, and the inner cable merely bent sideways.

An immediate panic call to the factory drew the response 'yes, we are aware of this issue and we are creating a Service Bulletin'. When I later visited the factory, I was shown the modification on their 2160 demonstrator.

It was the fitment of a guard cover over the fuel cut-off knob to prevent inadvertant operation.

Avions Pierre Robin treated the symptom, they did not cure the problem.

If any of you suspect that 'it has been sorted', sorry to dissapoint you. The reality is, if you operate the fuel cut-off knob in flight, you will have about 15 seconds of engine power left. This is approximately how long the fuel remaining in the float chamber will last. You have been advised.

And if any of you think I may be overstating this issue, please take a couple of minutes and find out what happened to our second HR 200, G-BWVG. In a nutshell, the student inadvertantly pulled the fuel cut-off, pushed it back in, and then, as originally intended, operated the carb heat. Unfortunately, the Instructor who was very young and fresh, hadn't been advised by the other more experienced instructors regarding the fuel cut-off. 15 seconds later, without any notice, the engine quit one mile from the field...at 800 feet. In the ensuing forced landing, the aircraft was completely written off. Most fortunately, both the student and the instructor walked away.

I am not being inventive, nor am I trying to be alarmist. atceng, the report you refer to should be debunked only at your peril. Sorry to sound so melodramatic, but I really don't want to read about another preventable accident.

camlobe

[BackPacker]

Just to add, on our R2160 (presumably more or less the same arrangement as the HR200 but with the guard cover as mentioned) it is standard practice to leave the fuel cut-off open at all times.

I found the knob pulled all the way out once (on the ground, during preflight) and fortunately it went all the way home when I pushed it back in, and stayed there.

Bowden cables are good for pulling actions. But as others have said, if they're not lubricated properly and exercised regularly, they're not that good for pushing actions.

[cockney steve]

Irrespective of maintenance, they are NOT designed for compression but are purely for tension loads.

2 alternatives....1- spring load the tap to "open" , arrange the remote knob to "pull and lock"-upon release the spring PULLS the cable back.

2 -substitute a Teleflex-Morse type cable which IS engineered to transmit push as well as pull-loading.

OK, tou COULD use a heavier, stiffer Bowden-cable to transmit the "push" load, but that's a bodge, not an engineered solution.

[atceng]

Many thanks for your invaluable inputs backed up by real practical experience.
You have given me a pretty thorough understanding of the parts,functions and limitations involved.
I will pass on the info to maintenance but personally I wont pull the knob unless I'm on fire.
Any more caveats on the HR200 would be much appreciated.

atceng


typo corrected