British European double engine failure at BRS

[flaps40]

Does anyone have any reliable information regarding the rumour that a British European Dash-8 suffered a double engine failure just before V1 at Bristol yesterday in the snow?

According to the rumour I heard the a/c stopped on the runway with no damage or injuries but this is a type which one expects to cope well with icing conditions...

[Flying Force]

Apparently it wasn't just before V1 but at the Hold waiting to Line up...

[MissChief]

That's just before V1 for a Dash 8, I reckon!

[Raw Data]

The truth is that it happened at the holding point. No damage to aircraft or pax.

Unfortunately most PT-6 powered turboprops are relatively susceptible to engine intake tract contamination or iceing- apparently this was the cause of the Shorts 360 accident at EDI a couple of weeks ago as well.

[touch&go]

Raw Data......How do you stop this icing?, I guess the the hot lips won't stop the icing problem.

[Oilhead]

Another turbo-prop incident and possible icing as a factor is emerging it seems. A ComAir Brazilia diverted into West Palm Beach sometime at the weekend. Seems it got caught up in icing and ran out of speed and lost a bunch of feet. Not sure of any injures, but the plane was damaged enough to be out of action. NTSB are down here.

[Deadleg]

Dash 8 are'nt fitted with PW PT6 engines!
They are PW123 which I have not heard of having too many probs unless oil temps are'nt high enough to provide heat or you let snow build up in the intake.

[Raw Data]

Sorry, left a word out... meant to say PT6-TYPE engines, ie engines with the air intake below the spinner and a plenum chamber leading, via by-pass vanes, to the engine air intake at the rear of the engine (kind of a PW trademark really).

The culprit here is a buildup of ice or snow inside the intake plenum... obviously hot lips won't fix that. It can be checked visually, or by sticking your hand in through the by-pass doors and feeling for contaminants.

[sambucca]

Raw Data's Right-Ice builds in the plenum chamber and when it lets lose it's lights out. This same thing happened to an Air Nova Dash 8 a number of years ago. The intake covers were not put in place when parked for the evening. Snow and ice accumulated in the plenum and unless you get a ladder to take a look you would never know. Next morning they fired up and took off out of St. John's NFLD and had a double flameout over the H2O at a few thousand feet when the ice melted enough to let loose. Luckily , they got at least one going again before getting wet.

[Lucky Angel]

Well I was there that day and what I heard was that the BE dash had power loss on taxying to the holding point. I saw the a/c doing engine runs about 30 mins later and we took of with our Brymon Dash 10 mins later with no problems. I've never heard of the Dash having this kind of a problem before.

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Fly high be safe !!

[Deadleg]

Of course the intake heaters work off 115vac to provide ANTI-ICE for the compressor intake flange. Any solids should pass out via the by-pass door. Naturally you should start with clean intakes just as you start with clean wings. Yes it is difficult to see in the intakes, but it is on jets such as DC9/B717, EMB145 etc also, so get a ladder!
I always check if there has been snow overnight or if there is any doubt of deposits, it only takes a minute.

[RATBOY]

A number of years ago got to lookat transport Canada's flight check Dash 8. They carried a whole set of intake and exhaust covers and ladders to secure the a/c when the had no RON at fun places like Churchill, etc.

The PT-6,as I understand it, is a reverse flow engine when mounted in the aviation appliciation (it was originally designed as a stationary power plant) so it would not be unexpected that a lot of ice/snow could build up. Is the rest of the PWC family of engines also "reverse flow"?

[xsbank]

I flew a Dash 7 for a while, and every night while the cojo filled out the logs, Captain Me took the bag of plugs out of the boot and stuck 'em in the various holes and tied down the props.

After every last flight of the day.

Every one.

Now I know why I did all that tedium, so many times. Oh yeah, one of us took 'em out again in the morning too.

Every Turbo comes out of the factory with a set, and if you have lost yours an upholstery shop will be pleased to make you more. They also work wonders at keeping out the odious mud-bird while waking up and enervating the crew with the morning s-t-r-e-t-c-h. This is especially entertaining when it rains and the crewmember is female, providing amusement for the rest of the crew to grade the unplugger on their form while they perform the wet-prop pirouette.

Takes 5 minutes to stick 'em in and will save you all kinds of grief, as well as a ton of paperwork.

[kennedy]

I'M SURE THAT THERE IS A AMENDENT IN THE FLIGHT MANUAL MARKED SAFETY OF FLIGHT THAT REFERS TO THIS SUBJECT SAYING SOMETHING LIKE IN ICING CONDITIONS ON THE GROUND WHERE DEPOSITS ARE POSSIBLE IT IS ESSENTIAL TO INSERT INTAKE COVERS TO PREVENT THIS PROBLEM

[MaxProp]

lucky angel and (kennedy)----this is a well documented problem with the dash 8 ---angel see safety of flight supplement no 4 which should be in your flight manual not to mention repeated at every Bombardier winter ops annual bulletin.

[Redline]

The a/c in question had already done 2 sectors so the overnight contamination theory doesn't work. The weather was horrendous-ish, snow etc.

[exjet]

Sambucca,
You seem to be right, if the intake covers are left off with a chance of water getting in ( over night) ice will form inside the intake which is very difficult to see unless you use a ladder.

The PT6 and PW123 are very different engines

[Ignition Override]

Flaps Forty-Goed evening!

As for the Pratt & Whitneys on Shorts 330/360s, strange problems in icing conditions go back to the mid 1980s.

And the CAA/FAA... or manufacturers (Shorts, DeHavilland etc) STILL have not required enough modifications to ignition systems/inlet anti-icing, in order to prevent such flame-outs? The ignition on the Saab-340 was supposedly modified years ago, due to certain concerns regarding continuous ignition (?).

What if the plane had been airborne with YOUR family onboard? Which plane will be next?

If one considers how much disturbing information was ignored by the US FAA (sent to the FAA from Italian or other European organizations), in order to avoid troubling icing certification questions and avoid expensive changes to the ATR-42 leading edge de-icing boots, until a tragedy (Roselawn, Indiana) took place within its "jurisdiction", it would not surprise me if many other things might have been "swept under the rug". If the documents appear to be in order (this was possible until thorough inflight icing tests behind a US Air Force KC-135 "water sprayer" were conducted only after the Roselawn tragedy), the "legal concepts" can often allow the ends to justify the means.

[This message has been edited by Ignition Override (edited 23 March 2001).]

[Deadleg]

I was flying that day from BRS in a Dash 8 & although bad I have seen worse in Scotland recently. I am not trying to prejudge anyone but to lose both engines in such conditions begs the question, were the intake bypass doors open & therefore the intake heaters on & were the igniters in 'manual'?
Easily missed, but I am very glad it happened
at the hold & all OK!!!

[chihuahua]

I recall that the problem of deposits building up is most likely to manifest itself when the aircraft rotates - the deposit is at this stage ingested into the engine.

[Capt Claret]

RATBOY,

Dash 8s are fitted with P&WC 100 series engines. The DH8-100 PWC12x and the DH8 200 & 300 with PWC123.

The 1 in the PWC 12x/123 indicates that the engine is a straight flow one, that is, air enters the front and passes through the engine exiting at the rear. The only reversal of direction being the combustion chambers.

The PT6 however, as you mentioned is reverse flow, the air entering from the rear of the engine and travelling forward to exit at the front.

All the PT6s I have operated used an inertial separator, which deflected into the airflow inside the plenum causing some torque loss, for ice protection.

The PWC100s as fitted to the Dash 8 uses plenum design to cause the airflow to enter the intake, travel to the rear of the plenum, then forward and upward into the engine intake. (Damned if I know how the air knows to do this though!)

A bypass door at the rear of the plenum (no performance loss, regardless of position) provides an escape route for 'solids', this bypass door has a shear mechanism to allow large foreign objects to 'break through' and exit the plenum. For ice protection, the bypass doors should be opened manually, which also serves to energise the intake lip heaters (115V variable AC).

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bottums up !

[This message has been edited by Capt Claret (edited 23 March 2001).]

[Alpine Flyer]

We fly the Dash 8 with bypass doors open all the time (unless the temperature goes above ISA+25 :-) so we don't have to open and close them all the time. We also plug the up (personally) for all night stops and extended stops with precip. Nasty but seems to help.

The only theory I can think of is snowfall during turn-around. There seems to be no way the nacelle plenum chamber can ice up during engine operation. A DHC engineer once told me they threw all kinds of objects into the nacelle during testing and never managed to get anything into the engine as all solids wouldn't go with the 270 degree turn the air is forced to make.

Vastly superior to the Dash 7 which lost lots of power with the intake deflectors open...when you needed it most.

The F.50 was retrofitted with a very elaborate system of heating mats in the bottom of the air intake to avoid freezing and later "spontaneous" departure of big chunks into the engine. Also some double flameouts before the mod came out.

[Whispering Giant]

Sounds very similar to problems encountered
during the development flying of the Bristol
Brittania in the early 50's.

[MaxProp]

Alpine flyer-- you are right that this incident occurred during turnround exactly as advertised in Supplement no 4(see previous post).

However, as far as icing during operation is concerned the last Bombardier advice (Oct 2000) was that the plenum chamber must be inspected if icing has been experienced in flight

[Navi-Gator]

I don't know too much about PT6's and PW whirly thingy's but Fuel + Sparks + a bit of air = lots of lovely flames - in the correct place of course.
if the AFM gives advice on the use of igniters, continuous or other wise it may stop a bad hair day if you comply.
Some Operators have issued internal memo's to restrict the use of igniters on replacement cost grounds ignore them.
It costs a lot more to replace an A/C let alone the grief it can cause on a personal level.

[nilnotedtks]

....Ah Bristol Britannia.....Proteus turbo-props....icing....Ahhhgh. no !