Primarily for general aviation discussion, but other aviation topics are also welcome.
#1870170
David Wood wrote:
VRB_20kt wrote:PB on Avweb suggested started the engine with the fuel supply turned off so that even if one got away it wouldn’t get very far. Never having used the Armstrong method I don’t know how viable that suggestion is.

I used to do that but I think it's a silly idea. My Moth will run on tickover for a good 2-3 minutes on the fuel in the lines and so if it does start moving it's going to have gone a fair way before it stops.


@David Wood I always solo start with the fuel off, and I'm intrigued to know why you think it's a "silly idea". What's the worse that can happen? Forgetting to turn it back on again? And that just means unbuckling, getting out, and going through the complete starting process again (been there, done that). I agree that an engine will run perhaps 2-3 minutes at tickover on the fuel in the lines - it will run a damn sight longer with the fuel on, whatever the power setting, so what is the gain?

Start with fuel on though, and what is the worse that can happen? Well, a few years ago I was in a fire-truck Land Rover chasing a pilotless biplane gyrating across the airfield on full power which eventually straightened up and took off - I still recall the sick feeling in my stomach - and was only stopped when it hit a tree at the airfield boundary, and piled in. I still don't understand how in it's gyrations it did not nose-over, or wipe the undercarriage off. Had the fuel been off, the whole incident would have been over in a fraction of the time, and a beautiful aeroplane would, probably, not have been totally wrecked.

And that's why I solo start always with the fuel off. I take the view that that there is potentially a lot to be gained, and very little to lose.

Rich
ChampChump, MichaelP, mick w and 1 others liked this
#1870178
MichaelP wrote:I watch on while the student thoughtlessly does the checklist.
The Cessna 172 started on the left tank, then the checklist tells the pilot to switch to the right tank... It’s only been running for less than a minute...
I ask: “When the fuel’s turned off, how long does it take for the engine to stop?” The student has no idea.
It takes two minutes or more, more time than switching tanks in accordance with the checklist, and so proves nothing.


When I followed checklists I used to have no idea how long the engine would run without fuel although I had read AAIB reports of aircraft getting airborne and having the engine stop just after takeoff.

One day I parked a pa28 and shutdown the engine. I got out and thought not my best parking attempt and decided to park it better. I restarted the engine with fuel off thinking I would have enough fuel to re-park by taxying through the adjacent parking space. The aircraft made a 90 degree turn before the engine stopped due to fuel starvation.
Whilst I felt particularly stupid making that mistake due to fatigue, I think I learned something from that.

Consequently I am in no rush to get through checks, because by taking a bit longer I know if there is a fuel supply problem it will still be more likely on the ground and not the climb out,

The old saying better to be on the ground wishing in the air, than being in the air wishing on the ground.
MichaelP liked this
#1870247
Rich V wrote:@David Wood I always solo start with the fuel off, and I'm intrigued to know why you think it's a "silly idea". What's the worse that can happen? Forgetting to turn it back on again? And that just means unbuckling, getting out, and going through the complete starting process again (been there, done that). I agree that an engine will run perhaps 2-3 minutes at tickover on the fuel in the lines - it will run a damn sight longer with the fuel on, whatever the power setting, so what is the gain?

Start with fuel on though, and what is the worse that can happen? Well, a few years ago I was in a fire-truck Land Rover chasing a pilotless biplane gyrating across the airfield on full power which eventually straightened up and took off - I still recall the sick feeling in my stomach - and was only stopped when it hit a tree at the airfield boundary, and piled in. I still don't understand how in it's gyrations it did not nose-over, or wipe the undercarriage off. Had the fuel been off, the whole incident would have been over in a fraction of the time, and a beautiful aeroplane would, probably, not have been totally wrecked.

And that's why I solo start always with the fuel off. I take the view that that there is potentially a lot to be gained, and very little to lose.

Rich


I suppose that that's true, and I'll think about it. The reason why I said that it's a silly idea (maybe that was a little unkind) is that it smacks slightly of tokenism to me. It's a bit like the "lower the nose every 500' to see ahead" advice - which IMHO gives the illusion of a proper look-out without actually achieving it.

So, to my eyes, starting the engine with the fuel off just in case the aeroplane runs away at a high throttle-setting seems to me to be in the same category; no disrespect implied. I've never experimented to see how long the engine would run at an open throttle setting with the fuel off, but I'm guessing it would be long enough to cover some yards, if the chocks weren't in. So the best mitigation there is to make sure that the chocks are in and that the stick is tied or held back. Then the engine can run as hard as it likes and the aeroplane isn't going to move.

I guess my logic is this: given the rigmarole that I go through when hand-starting I consider that the likelihood of me starting the engine with the throttle in the wrong position AND no chocks in place to be so infinitesimally small as to be discountable (famous last words, I know). Whereas there is a real risk of the aeroplane starting to move after I've moved the chocks and before I've climbed in. So that's where I focus the risk-mitigation.
#1870300
Like the “pebbles in front of wheels” I always try to find somewhere I can drop the tailwheel into like a drain, manhole or flower bed if there is nowhere to tie it to. It’s amazing how small a depression you need with a small diameter wheel to stop movement whilst collecting/stowing chocks etc.
What I am paranoid about is “blowing out” where the normal procedure is full throttle. The amount of live mags I’ve seen over the years……….. Will NOT blow out without qualified bod in cockpit ( as well as all the usual checks of course)