DA42 crashed in Northern Germany

[achimha]

Terrible accident near the Airport Parchim (http://www.parchim-airport.com/en/html/index.asp) in North Eastern Germany.

Swiss registered plane, 4 on board, pilot and wife fatally injured, the others severely injured. Accident happened right after takeoff from Parchim, destination Basel in Switzerland. Shortly before the crash, the pilot reported technical difficulties. The airplane crashed on an open field and slid into a forest.

http://www.abendblatt.de/multimedia/archive/01168/Parchim9_HA_Bilder_1168766b.jpg
http://www.abendblatt.de/multimedia/archive/01168/Parchim5_HA_Bilder_1168762b.jpg

Picture gallery here (http://www.abendblatt.de/region/article2289696/Flugzeugabsturz-bei-Parchim.html).

[Hodja]

Looks like the aircraft had an almost direct head-on impact with the trees. The whole airframe is broken up.

Only positive angle to this crash, as the article notes: No post impact fire.

Something severe must have happened. Single/multiple engine failure at a critical stage? Electrical fire in the cockpit?

[englishal]

Or a badly handled emergency. Horrible crash & it is a wonder anyone survived. Had this been a non composite, "old" airframe I think there would have been 4 fatalities.

[B2N2]

That trip looks to be around 500NM or about 3.5 hrs flying time.
80% cruise power for 12 gallons/hr for 42 gallons fuel required.
With full main tanks only (50 gallons) they would have had sufficient VFR reserves.

Some assumptions here but with full main tanks (350lbs) leaves about 700lbs for 4 people, luggage and maybe TKS fluid as the airplane was TKS equipped.
700/4= 175 lbs average passenger weight with personal luggage allowance included.
At least in the pictures there seems to be a debris path of luggage and personal items.
I'd be interested in the W&B on this one and also in the location of the rear canopy. I guess you would put the non flying passengers in the back.
Possible rear canopy opening during climbout with the pilot reaching back and trying to close it?

[achimha]

Several news articles report that a surviving passenger mentioned engine issues to the police. The airplane was equipped with Thielert engines.

[B2N2]

Überlebenden, ein Mann und eine Frau, kamen in Krankenhäuser in Hamburg und Schwerin. Die Frau soll den Rettungskräften bei ihrer Bergung erklärt haben, dass ein Motorschaden Grund des Absturzes gewesen sein könnte.


Apparently the surviving female victim mentioned possible engine trouble to rescue crews.

Source: Meldung: Tote bei Flugzeugabsturz nahe Parchim vermutlich Schweizer - Nachrichten Newsticker - News3 (DAPD) - WELT ONLINE (http://www.welt.de/newsticker/news3/article106385821/Tote-bei-Flugzeugabsturz-nahe-Parchim-vermutlich-Schweizer.html)

[peterh337]

Engine issues in both engines of a twin are usually fuel (lack of)... or (IIRC) in the case of the DA42 an alternator failure following a departure with a flat battery.

That trip looks to be around 500NM or about 3.5 hrs flying time.
80% cruise power for 12 gallons/hr for 42 gallons fuel required.
With full main tanks only (50 gallons) they would have had sufficient VFR reserves.

That's a very "interesting" fuel calculation, B2N2.... 8 gallons in the tanks at the planned destination? I burn ~11 USG/hr and my absolute min would be 20 gallons. 8 is so low that one needs to read the POH to see how much sideslip is allowed before one unmasks the tank outlet :)

[Hodja]

Pure speculation, but maybe it went something like this:

Overweight or max weight take-off (4 persons & fuel for 4 hrs?), single engine failure & slightly botched emergency recovery -> crash.

I can't help but think, that it's also a lot easier for a pilot to get distracted & lose precious reaction time w/4 people in the cabin, including family members...

[B2N2]

8 gallons in the tanks at the planned destination?

In the DA 42 fuel burn is 6G/hr per engine at 80% power.
So 8 gallons remaining over two tanks is actually (almost) required IFR reserves of 45 min at 75% power.
No matter how you look at it it's legal but fairly tight for a 500 NM flight.

If this aircaft has the long range tanks installed and filled with an additional 26 gallons the aircraft would have been 182 lbs (26 x7) overweight with the previous assumption of 175 lbs/pax + luggage.
The CG arm for the aux fuel tanks is 126 inches which is almost the same as the rear passenger CG arm which is 128.
This means that with 2 rear passengers and fuel in the aux tanks max aft CG is exceeded. It essentially means the weight of three adults in the rear seats.
Exceeding aft CG plus engine problem.................

**** the above is all purely scenario based speculation and does not imply in any way shape or form that I know or claim to know the cause of this accident ****

For all I know they had three fuel stops planned and no aux tanks installed.

[peterh337]

So 8 gallons remaining over two tanks is actually (almost) required IFR reserves of 45 min at 75% power.

Legal but very very tight.

[Fuji Abound]

FWIW, and no reflection on this accident, I have a few engine failures at MTOW after take off in the 42. Its ok, but you do need to be on your game, and their isnt bags of surplus power. Being over weight would not be a good idea as I suspect there is not much margin.

[AndiKunzi]

FWIW, and no reflection on this accident, I have a few engine failures at MTOW after take off in the 42.Hi Fuji,

you mean you've experienced yourself several real engine failures in a DA42 after take-off?? :rolleyes: Or do you mean simulated ones in a safe height above the field?

Anyhow, OEI performance on Thielert powered DA42s at MTOM was reported to be insufficient in a couple of incidents before. And engine issues seem to be more frequent than on LyContiSaurus.

Training with actually shutting down can be done safely and close to reality, simulating an imaginary runway at 5.000 ft, for instance, ground being at 1.000 ft. Doing this once a year in my Seneca II, to stay ahead in case I need it.

Best regards,

Andi

[peterh337]

Diesel engine failures are way more common than Lyco/Conti engine failures.

Where I am based there is an FTO operating several of these and it is a fairly common sight to see them taxiing in followed by a fire engine. Obviously these are not (usually!) cases where a piston is sticking out of the cowling, but some sort of engine issue nevertheless.

[AN2 Driver]

Diesel engine failures are way more common than Lyco/Conti engine failures.

Any reliable and founded stats on this?

Naturally, Centurion/Thielert claim the opposite.

Would be nice to have figures.

[peterh337]

... and Mr Dries could sell Mars bars to Bobby Sands.

[Big Pistons Forever]

Training with actually shutting down can be done safely and close to reality, simulating an imaginary runway at 5.000 ft, for instance, ground being at 1.000 ft. Doing this once a year in my Seneca II, to stay ahead in case I need it.

Best regards,

Andi

I very much disagree with the practice of deliberately shutting down and engine in flight. Aside from the fact it is brutally hard on the engine there is a very real possibility that you can't get it started again.

Canada used to require that an actual shut down be carried out when training for the multi rating (they finally stopped this foolishness 3 years ago). I have on two occasions been unable to restart the engine.

I declared an emergency both times as by my own actions I converted a perfectly servicable aircraft into one with a 90% reduction in its rate of climb, a minimum inflight speed limit and the inability to reject a landing when below 500 feet.

For what ? The exact same effect can be achieved by leaving the engine running at zero thrust !

[Fuji Abound]

Andi

My efatos in the 42 have all been simulated. Unlike some twins the performance is sufficient to enable the aircraft to climb positively at mtow and perhaps even more importantly the handling is docile. However the point i was making previously is there is only a small surplus of power; over use of the controls and failure to keep the aircraft balanced will erode the surplus that is available and the aircraft will quickly cease to climb. Over mtow and i guess there is no margin, unlike for example an aztec where you barely notice the loss of an engine such are the performance reserves. I have had a real engine failure in the cruise which is a different kettle of fish.

As to the reliability of the engines / aircraft i am not sure how much evidence there is to back up some of the assertions. There is little reason to think the engine is any less reliable in 42s compared with 40s. I read of very few 40s suffering engine failure, events which would almost always be reported, even if a failure in a twin might go unreported. If anyone has statistics to the contrary that would be interesting.

Thats not to say that such is the monitoring of the engines that more potential issues might be flagged in flight that with other conventional engines and this in part might explain some aborted flights.

As to simulated engine failures in twins i dont see what evidence there is for this action being harsh on a 42. The engine is water cooled and so long as the engine has not been running at a high power setting prior to the shut down why should this be any different to a ground shut down after giving time for the turbo charger to cool. I would agree a shut down from a high power setting would be unkind, albeit par for the couse given the number of 42s one sees roll up on the apron followed by the pilot immediately switching off both engines. I had an engine failure on my initial multi in so far as we couldnt restart the engine; so i would agree an intentional in flight shut down is a risky strategy. I think in a 42 this is less true because the restart is very straight forward and difficult to get wrong. Moreover the aircraft handles far worse with one engine at very low power settings than with the engine shut down and prop fethered. On the other handle with the conventional six levers, twin mags and often difficult injected big sixes it does seem to me the pilot has much to learn from an inflight restart. However, how often will a pilot shut down an engine and subquently elect an in flight start? The excercise is to give experience of flying the aircraft on one engine and experience of how to shut down the engine in the first place. Does the engine need to be actually shut down in flight to give this experience, probably not

[englishal]

The DA42 will climb quite well on one engine at MTOW and is pretty docile as mentioned. If you trim out the rudder it really isn't much of an issue flying on one engine especially once you have feathered the prop (master switch OFF). However like all twins, if not handled correctly then things can go wrong pretty damn fast.

There was an incident some time ago where a DA42 took off after having a flat battery. They started it with ground power then took off. When the gear was raised the ECUs both tripped out (lack of power) and both engines stopped. However the procedures were changed so that if you have a flat battery then you only start ONE engine from ground power and start the other normally. This ensures there is enough power in the battery to raise the gear without causing low voltage conditions.

I haven't heard of many mechanical problems to the Thielert which have caused a catastrophic failure as in the Lycoming type of failure. I did once have a turbo boost problem on one engine when climbing through 8000', the right engine power reduced to 75-80% and kept reducing with altitude (left stayed at 100%), but it wasn't an issue low down.

[Fuji Abound]

Englishal

Interesting, I wouldn't entirely agree.

I felt the 42 at MTOW climbs away on one engine but the performance is hardly sparkling and unless the aircraft is correctly trimmed it struggles.

Purely my own observations.

Not to say there aren't twins that are worse and a few much better.

[mikehallam]

I thought diesel fuel was denser than petrol ?
(petrol has densities range ~0.72 -0.74).

But I see above folk calculating fuel load using 7lb per gallon.

So s that UK 4,54 litres gallon petrol or a US gasoline @ 3.8 something per gal.?

mike hallam.

[Hodja]

Not to say there aren't twins that are worse and a few much better.Even a King Air can get into trouble in an EFATO scenario if not handled correctly...

NTSB (http://www.ntsb.gov/aviationquery/brief.aspx?ev_id=20110316X63443&key=1)

[B2N2]

So s that UK 4,54 litres gallon petrol or a US gasoline @ 3.8 something per gal.?



Jet A is 7.01 lbs/ US gallon at 15 Celsius
Elevation of Parchim is 166 feet or 51 meters so I doubt that density altitude played a role, especially with turbo normalized engines.

Not to say there aren't twins that are worse and a few much better.

Any certified twin needs to meet certification requirements so the DA42 is no better or worse then other certified aircraft.
This is not a DA42 airplane issue.
No plane will save you if you are not proficient at what you are doing.

ERA12FA123 (http://www.ntsb.gov/aviationquery/brief.aspx?ev_id=20111226X45311&key=1)

ERA09FA303 (http://www.ntsb.gov/aviationquery/brief.aspx?ev_id=20090525X10534&key=1)

[FlyingStone]

Any certified twin needs to meet certification requirements so the DA42 is no better or worse then other certified aircraft.

And no light piston twins is required to show positive single-engine climb gradient during the certification process. The part 23 aircraft only have to show steady climb gradient, not a positive one.

Elevation of Parchim is 166 feet or 51 meters so I doubt that density altitude played a role, especially with turbo normalized engines.

Both Thielert TAE-125 and AustroEngine AE300 turbodiesel engines are normal turbo engines, they aren't turbonormalised. In TAE-125 the manifold pressure at takeoff power is about 2.3 bar (~ 70"), which is approximately the same as in car turbodiesel engines. The catch is that maximum load (100%) can only be achieved up to 5-6 000ft, where as for example in Seneca (TSIO-360), you get maximum brake horsepower at 13000ft.

[B2N2]

Well it's really a hybrid turbo normalized.
The turbo provides some boost at sealevel but 37PSI and not 70.
The 37 PSI level is maintained till the critical altitude of the turbo through a ECU controlled waste gate but we're getting totally off topic here.

The Seneca works differently but thats for another day.

[Fuji Abound]

Hodga

Of course but some twins are much more forgiving after an EFATO.

[B2N2]

Any news or preliminary reports?

[Hodja]

Page 61:

http://www.bfu-web.de/cln_030/nn_223532/DE/Publikationen/Bulletins/2012/Bulletin2012-05,templateId=raw,property=publicationFile.pdf/Bulletin2012-05.pdf

[172driver]

Going through the reports and looking at the images, it always amazes me how little remains after a crash.

[achimha]

Rough translation:

During initial climb, there was a problem with the engine(s). While turning back to the airport, the aircraft crashed into a meadow.

The pilot stated that he planned a multi day excursion together with his wife and an acquaintance. On 24.05.2012 at 07:00 he took off with his DA 42 at Berne/Switzerland for a flight to Sylt [German North Sea island, at the Danish border]. The passengers were supposed to be dropped off there while the pilot continued to Billund/Denmark for a business meeting and was supposed to return on the following day. The flight from Berne to Sylt was without problems at first. While approaching Sylt, the pilot noticed a drop in power in the right engine of about 5-10% which he compensated for by increasing the power.

During takeoff run at Sylt for the trip to Billund there was engine roughness and the right engine stopped. The takeoff was aborted. Mechanics of the German Diamond service station were ordered to come to Sylt. On site, maintenance and an error diagnosis were performed, during which a prop governor valve was replaced. After a test run and test flight, the aircraft was returned to the pilot the following day.

On 26.05.2012 the pilot took off for the follow on flight to Parchim with the passengers on board. The 90 minute flight was uneventful according to the pilot.

The flight back to Bale was planned for 28.05.2012.

At 13:27, the pilot reported on the radio and requested a startup clearance for an IFR flight to Bale. At 13:40 a takeoff clearance was issued on runway 24 by the control tower Parchim. The pilot reported at 13:41:19: "We do a right turn as planned [...] and I am rolling now." The next report occured at 13:43:03: "[...] I need to return to the field I have an engine failure on the right engine." In response to a request by the tower, the pilot confirmed that he intends to return to the airfield due to an engine failure and wants to land on runway 06. The tower then issued a landing clearance for all runways at 13:43:41. At 13:43:44, the pilot issued his last report: "All runways (incomprehensible) to the field to (broken up)". Witnesses saw the aircraft, coming from the north west, in a right turn with low bank over the airfield.

Shortly thereafter, the aircraft crashed into a meadow close to the airport Parchim.

[Skipping pilot details, aircraft, details, weather as nothing special, weather CAVOK, etc.]

Engine examination

The engine was examined by the BFU [German aircraft accident investiation authority] at the manufacturer's premises. While disassembling the gearbox, it was noticed that within the gearbox there was a larger quantity of thread-like material. The friction disk was completely worn down. At the edges were cracks. There were traces of a liquid on the gearbox entry shaft and abrasion on a bearing...

[some FADEC graphics]

Due to design, the timelines on the FADECs are not synchronized. In the chart, the moment of power increase were aligned (start of take off run). From this, it can be determined that both engines were running for about 3 minutes.

The data for both engines ends prematurely. The RPM of the engines at the time of impact:

right engine: 2 579 rpm
left engine: 3 944 rpm

The FADEC data on the right engine shows a slowly but steadily increasing overspeed up to 4 517 rpm (about 270 prop rpm), instead of 300/min engine rpm (200/min prop rpm). The overspeed starts about 40 seconds after setting the power lever to maximum and ends about 85 seconds after setting the power lever to maximum. After that, the pilot fully pulls back the power lever of the right engine (LOAD to 0%). The altitude reached during these 85 seconds corresponds to a pressure difference of 16 mbar.

The right engine settles on a speed of 1500-1600 rpm, roughly corresponding to idle speed. About 78 seconds after the pilot reduces the power setting to 0%, it is increased for a short moment to 11%. The speed increases to 2 447 engine rpm and remains on this value, even though the power setting was reduced again after one second.

Fire

There was no fire.

[achimha]

So the right gearbox packed up which caused the right engine to fail.

However, one engine should be enough so it was probably improper piloting after experiencing a partial engine loss.

[B2N2]

My German reading skills are barely adequate but it appears the RH propeller was not feathered and for some reason the RH throttle was brought up as the LH throttle was pulled back at around 155 seconds, 20 seconds before impact. (page 69)

[achimha]

It doesn't say that, it talks about the power settings over time. On impact, the right engine was on idle RPM. I'll complete my translation above.

[B2N2]

Well, looking at the graph it is hard for the engine to be shut down and the propeller feathered with 1500RPM showing for 70 seconds prior to it going up again to 2579RPM at the time of impact.
I can't copy paste the graph here but it's on page 69.
Anything on the weight and balance information?

[172driver]

Anything on the weight and balance information?

The report states
- pax (incl pilot) 279kg = 615 lbs
- bags 47kg = 103 lbs

So total load (ex fuel) 718lbs. Doesn't say anything about C of G.

[Hodja]

I wonder what exactly went on there.

1. Did he physically try to feather the RH engine?

2. If yes, did something prevent the governor from actually feathering the prop & what could plausibly have prevented this? Did the RPM overspeed condition somehow confuse the FADEC?

3. If no, perhaps the engine was generating reduced power and somehow he thought he could bring it back to life? (although this would definitely have been a straight identify-verify-feather case, given the altitude)

Also the Diamond Service Centre didn't exactly come out well in this incident, given that they declared the engine fit for service 2 days before...

[englishal]

Feathering the prop on a DA42 is a simple case of switching the engine master switch off. Retarding the left throttle would be a normal way to recover from a right engine failure if you had let the speed decrease to near Vmc. Advancing the RH throttle would also be normal if you suspected the RH engine might be developing power.