PDA

View Full Version : Back in the air after long break - one drama and a real lesson


kevmusic
24th Mar 2011, 19:57
I have gradually come to feel ready for that first dual, and some solo flying. I duly booked out the Tiger Club's Jodel D150 and arrived today, a glorious early Spring day, looking forward to getting airborne again.

I fuelled up and did the walk-round, noticing a small un-filed nick in the leading edge of a prop blade. I pointed this out to my check pilot, who said he'd get it sorted after we landed, and top marks to me for finding it. As we settled in I pointed out that I'd lost my checklist for the Jodel ages ago. "Good", he said. "Prefer you not to use them". Okay. So going from memory, logic and some prompting I did the pre-start and start-up checks and the engine burbled in to life in short order.

The flight proceeded well and comfortably: I'd elected to go south, up to about 2,500', to do some general handling with steep turns and stalls. Come the first stall I did the HASELL check then set up idle power with carb heat, gradually pulling back on the stick, alert for the signs of the impending stall. We were quite nose-up when it happened: the nose dropped......and the engine died. Engine failure!

The prop was still turning, so I lowered the nose a little further to increase the revolutions, added a whisker of throttle - and she burst back into life!

Something about that manouevre stalled the engine.......or could it have been carb ice? My check pilot didn't know either. At any rate we went for another stall (the engine still running sweetly) this time with about 1,000 revs; there were no further problems.

I wasn't particularly worried - there was something about the way the donk stopped that made me think she might start again, and we were at 2.5k over good forced-landing country, where we'd both been many times before (local practice area).

So we went on to circuits. They were a bit ragged at first but I tidied them up and was offered a couple solo, so I went for it. It was great! Just a couple of circiuts of a grass field on a beautiful day, and I began to feel good.

I got off the runway, did my post-landing checks and taxied to the clubhouse, trying to remember the shutdown checks. I parked to position myself by hand, rather than use coarse power settings to manouevre close to the clubhouse. I thought I did everything in the correct sequence, remembering the mag check before ICO. Silence, except for the gyros winding down, and I found myself being moved around and pushed back while still in the cockpit.

And then I did something very foolish. I unstrapped and was taking off my headset when I heard a voice from upfront by the prop. My check pilot had said something - a query, by the look on his face - with a thumbs down. My mistake was to assume he'd asked if everything was off. I gave him a nod and a thumbs up.

Master switch!! Too late - he was turning the prop by hand just as I pulled the forgotten master! Well, nothing happened. He and the engineer inspected the nicked blade and a file appeared. I made a note of the tacho reading and made my exit.

All in all, a good day, but one in which I learned thoughtful lessons about not to assume someone has said something when I wasn't really sure, and not being sure when is a good time to be giving up checklists (ever?), plus there's nothing like knowing that those HASELL checks really do help keep you safe.

Finally, I loved to talk to Mrs. Km about my flying, but I'm not so sure she'd have wanted to hear all the details of this one.

kevmusic
24th Mar 2011, 22:06
Yep. Everything else was off- just forgotten to pull the master.

'Chuffer' Dandridge
24th Mar 2011, 22:15
27th picture down - Jodel D.150 (http://forums.airshows.co.uk/viewtopic.php?f=32&t=31672)

Looking at the lovely trail of black smoke along the lower fuselage, I wonder if there's something else which could have caused your engine to stop?:confused:

stiknruda
24th Mar 2011, 22:23
Kev - when I am hand swinging or being hand-swung, thumbs down means mags are OFF. The Master switch has no relevance - apart from running the battery down.

Your engine stop is probably quite explainable, too - though before I pontificate at length, I'd like to know how much fuel was onboard - the tank wasn't completely full, was it?! Go figure! (I'll help if you need it).


Al

kevmusic
24th Mar 2011, 22:38
Used the same tank throughout the sortie. The high alpha caused fuel starvation?

I always understood the master had to be off to ensure complete safety - in case of circuite failure in the mags somewhere.

@Chuffer - the smoke stains. Given the album's title, a fairly recent pic, but not today's, I think. Care to elucidate?

I re-fuelled before the flight, the wing tanks only. We were flying on the port tank which, by the time I was on my last downwind, was reading slightly above half-full.

'Chuffer' Dandridge
24th Mar 2011, 22:51
Half full wing tank on the D.150= 4 gallons, enough for just under an hours flight. Of course, you would have had the aux fuel pump selected on as part of your HASELL checks wouldn't you? I would have used either tank in turn and balanced the fuel equally for the sortie, but hey, what do I know?

I still reckon the idle mixture is set incorrectly. That much smoke staining is not right, but hey, what do I know? :rolleyes:

The pic was taken last weekend :-)

kevmusic
24th Mar 2011, 23:07
but hey, what do I know? :rolleyes:

Steady on! I'm grateful for any help! :) I'm at this stage of training - one instructor (pre-PPL) advised very prescriptive fuel management on the Jodel, including switching tanks before take-off. Today's check pilot (I'm now a PPL, but worryingly under-experienced) wasn't bothered about changing tanks at any stage, despite my queries. I mentally filed a future query because I hold my original instructor in very high regard. I merely wondered about the significance of the smoke stains along the under-fuselage.

Genghis the Engineer
24th Mar 2011, 23:11
Master switch doesn't affect ignition. Well done on flagging that you did something wrong, you didn't endanger anybody, but you might want to spend a bit of time with the POH? Your check pilot should probably have made a point of asking if the switches are off as well mind you.

Personally, I always have a checklist with me, if only for ground checks. I can't say I agree with somebody who prefers a rusty pilot to work from memory.

Sounds like idle RPM may have been a bit low. Easily adjusted, but best speak to a ground engineer before it's flown again, AND make a tech log entry.

G

Crash one
24th Mar 2011, 23:16
I always understood the master had to be off to ensure complete safety - in case of circuite failure in the mags somewhere.

Mags are completely independent of master/battery circuits.
A fault in a mag earthing wire could allow the mag to be "live" regardless of even the existence of the battery.
Black smoke? could that have been a "rich cut" situation? Just guessing.

SNS3Guppy
24th Mar 2011, 23:18
As we settled in I pointed out that I'd lost my checklist for the Jodel ages ago. "Good", he said. "Prefer you not to use them". Okay.

No, not okay. Your instructor is an idiot.

I always understood the master had to be off to ensure complete safety - in case of circuite failure in the mags somewhere.

No. The reason you have magnetos is because they produce their own electrical impulse, and are completely independent of the aircraft electrical system. Battery master switch on or off makes no difference. If you experience an electrical failure in flight with no aircraft electrical system available, it won't affect your magnetos. The only thing necessary for them to produce an electrical impulse is rotation.

The "circuit failure" that can occur in the magneto/ignition switch circuitry is a failure of the grounding "p lead" or "earthing lead" to the magnetos. If this occurs, the mag can be made to cause an electrical impulse, generating a spark at the spark plug, regardless of the ignition switch/mag switch position. This has nothing to do with the master switch, however.

We were quite nose-up when it happened: the nose dropped......and the engine died. Engine failure!

The prop was still turning, so I lowered the nose a little further to increase the revolutions, added a whisker of throttle - and she burst back into life!

It bumped back to life because you had propeller rotation, and magnetos producing electrical impulses for the spark plugs, as a result of that rotation.

It likely quit because of carburetion issues. More than one pilot has found himself without power when doing push-overs involving less than a positive G, causing the float in the carburetor to "float," sometimes sticking. The end result can be an unrecoverable power loss.

If you had carburetor ice, it was already forming; simply pitching up and then pitching down doesn't cause the problem. An ice buildup under extreme icing conditions, can happen quickly. Whereas you didn't report it during any other part of your flight, this was most likely not the case. Try less aggressive pitching next time, and allow a wing to fall off to unload the airplane rather than pushing the nose over. Your airplane isn't really meant to leave you floating in your seat.

kevmusic
24th Mar 2011, 23:37
The Aeroplane, Technical (Air Pilot's Manual): Amazon.co.uk: Trevor Thom, Peter Godwin: Books


Time for a re-read :hmm:

You guys have been fantastic, as ever. I so want to fly as much as my resources and time allow, being as good a pilot as I can within these constraints. There's not a lot in flying comes free but this forum and the advice it contains are worth a gold mine.

Beer talking now :O- time to go to bed!

Rod1
25th Mar 2011, 11:11
“As we settled in I pointed out that I'd lost my checklist for the Jodel ages ago. "Good", he said. "Prefer you not to use them". Okay.”

Good, really bad idea for simple light aircraft, the vital actions model is much better.

The only problem with leaving the master on when someone is moving the prop is an outside chance that the starter could engage.

Rod1

SNS3Guppy
25th Mar 2011, 11:25
A checklist has every bit as much application in a light airplane as it does in a complex airplane.

Leaving the master switch on is a good case in point. After the flows were completed the checklist would have caught that.

BackPacker
25th Mar 2011, 11:35
and I found myself being moved around and pushed back while still in the cockpit.

Nobody moves my airplane after shutdown until I'm good and ready. That's why I've got the brakes on while shutting down.

And I'm only good and ready once I've looked over the whole cockpit and confirmed that all switches are off.


My check pilot had said something - a query, by the look on his face - with a thumbs down. My mistake was to assume he'd asked if everything was off. I gave him a nod and a thumbs up.

The informal procedure at my club for working near a potentially live prop is simple. You either check for yourself whether the mags are off and the mixture is ICO, or you ask the person in the cockpit to show you the keys. (Obviously this only works in an aircraft that has a key-operated mag switch.)

I can imagine that you have specific hand signals when hand-propping, but I would not assume that these signals are familiar to pilots who have never done so.

SkyCamMK
25th Mar 2011, 13:17
I am wondering if your "Check Pilot" was a suitably qualified instructor from his reported comments?

DeeCee
25th Mar 2011, 13:44
Nice pictures, but I didn't see one of the 'non radio Llama' anywhere!