Swearingen SA-226-TC accident - assymetric fuel?

[barit1]

Feb. 8 fatal accident:

http://www.ntsb.gov/ntsb/brief.asp?ev_id=20060213X00194&key=1

[Dagger Dirk]

Well that's what happened to that Air Tahoma DHL CV580 turboprop that went down on finals to Cincinnati on 13 Aug 04. link (http://www.iasa.com.au/folders/Safety_Issues/others/AirTahoma185.html)
.
I guess forgetting a crossfeed set-up can lead to an imbalance and then be compounded by a flame-out on one side.

[ironbutt57]

Two very different systems on these aircraft...a Metro has a cross-FLOW system which simply lets fuel flow from one wing to the other....his requests for "360" turns seem to indicate an attempt to cause fuel to flow from one wing to the other..however in a co-ordinated turn this would not occur, a short time crossed controls in level flight would have done the trick.....the CV-580 has a cross-FEED system which allows an engine to be supplied fuel by the opposite wing...care has to be taken when performing this procedure...especisally if one opts to switch off the "tank valve" which the checklist calls for, but is entirely unnecessary....cant see how a huge fuel imbalance in either aircraft is worth dying over however...

[jondc9]

I flew the SA 226 and 227 (metroliner) about 20 years ago. It was a POS then and I am sure it is even worse now.

Yes, it is a cross-flow system and not a cross feed system. Another POS idea if you ask me.

That the pilot could and did execute two 360degree turns in opposite directions (verified by radar track) tells me that it should have had the capacity to land under full control right away. Of course the pilot ( solo, in pax ops we had two pilots) may have been trying to "fix things" and continue on rather than risk firing by his employers.

IT IS interesting to note that pieces of prop found away from main crash site. I do recall one scenario near fresno, ca when one of our planes had a prop break apart in flight, causing the engine to "cant" in its mount. plane was virtually unflyable at speeds below 200+ knots...miracle happend to be that plane was in cruise, all lined up with KFAT airport main runway...they landed safely.

even if all the fuel migrated to the opposite wing, causing flame out in "lighter wing" engine, the plane might have been controllable.

thanks for posting this crash info.


regards

jon

[ironbutt57]

Yeah the Fresno event was my former employer, and the Capt went on to bigger and better things.....Metro's in my opinion are ok, but some things could have been done better as far as tech engineering...

[jondc9]

hey ironbutt57

I worked for the same joint ( wings west) shoot me an e mail, maybe we know each other.

jon

[email protected]

[capnflyright]

From personal experience on the metro this may shed some light. Have you ever watched fuel run uphill? We had an imbalance once and opened the cross flow. We put the high wing up and the low wing down to let gravity take over. The fuel ran uphill to the high wing. Later inspection once we were on the ground solved the anti-physics problem. The fuel cap was missing.

[Ignition Override]

Dagger Dirk, how do you and the other pilots remind yourself that you are crossfeeding?

Apparently the Martin 202/404 crash in which several members of the Lynyrd Skynyrd band died, was because of both engines failing after the pilots forgot that crossfeeding was taking place.

Was serious fatigue also a factor?

[Dagger Dirk]

Dagger Dirk, how do you and the other pilots remind yourself that you are crossfeeding?
I move my wristwatch from my left wrist to my right wrist. Always worked well for me.

[jondc9]

there is always some gimmick to remind you about crossfeed/crossflow...the fuelers used to hate me in SFO because I wouldn't crossflow on the ground. they would have to fill each wing instead of just one wing.

on the metroliner ( sa227/6) some would turn on the ignition to have the lights bright in their face at night.

during daylight I would put a piece of paper or a checklist in plain view covering up something in my instrument scan (only in day vfr at level cruise of course)...it was so annoying that one couldn't forget the cross flow. if on instruments I would hold the checklist in my hand...got old fast.

I suppose their should have been a timer to ring a bell or something...but the motto was, "crossflow once and you will have to crossflow twice">

[Defenestrator]

I've many years on the SA227 AC/DC and limited time on the 226. However the crossflow system is by and large a different beast in each individual build ie, if you've flown one metro......you've flown one metro.
I only recall one aircraft in which the crossflow was predictable. In level balanced flight the fuel would balance. Creating a slip would expedite the process. Yet on another much newer model with the crossflow opened in level unaccelerated flight the fuel would flow from the low tank to the high to the point where if left unchecked I would expect that it would have vented overboard. Opening the C/F whilst refueling was a pointless exercise as the rate of flow from one wing to the other was much slower than the fuel being introduced over the wing. The crossflow line linked the forward collector tanks and was rather limiting in flow.
The dangers of this system have been tragically highlighted by this accident. If nothing else I hope it brings some recommendations for the use of this system WRT balancing fuel between tanks. Exercise care and never, ever, allow the process to go unchecked for more than a couple of minutes.
D:uhoh:

[RAT 5]

Egg timer works for me. Some a/c builders thought it such a good idea they charge mega $ to install one in the overhead panel. Couple of pounds at Boots does just the same.

[ironbutt57]

Gee, I was quite sure the Van-Zant fellow (Lynrd Skynrd band) was in a CV-240 which crashed near Mc Comb Missippi due to complete fuel exhaustion...