Even though it's more than a decade that I flew the Fokker, I remember very well that the spinner of the engine was prone to ice up and cause vibrations, which could be stopped by reducing thrust. A modification was introduced by RollsRoyce, however, many carriers decided not to modify their fleets.
According to a friend of mine who is an ex-Fokker testpilot, preliminary information suggests that engine-vibrations due to ice caused the crew to reduce thrust. However, according to him, the engine is capable of shedding the ice by advancing thrust rapidly(one engine at a time of course). It seems that this was not attempted by the crew.
Facing an imminent crash-landing, trying to advance thrust even if it possibly destroyes the engines, seems to me good airmanship (remember Air Florida, where the pilots also never advanced thrust despite going down).
For the sake of the crew I hope my friends preliminary infos turn out to be incorrect.

Standard means of shedding ice from an iced-up fan is to apply a short, sharp application of power to the affected engine(s). The short increase in power, effectively, 'warps' the fan blade such that the ice is shed. This is particularly relevant during the approach phase when the engines are operating at lower thrust settings.

This would be the case if the engine anti-ice system had failed or had not been selected.

The RR Tay 620/650 engine is a good engine provided you look after it.

Mexicana had a lot of problems with their F100s. I was jump seating in XA-LXG when we shut-down the rigth engine over MTY a few years ago. It was deu to excesive vibration. Don't remember if the mods were installed on all planes.

They will be phased out beginning of next year anyway...

The Ultimate Skiplane
 

Just what you need to take dozens of friends ice fishing on frozen lakes:O

More seriously, it's likely a structural writeoff.

Kudos in order to Fokker for an airframe that stayed in one piece and to the pilots who had very little time for a brilliant improvisation.

Der Bauer deserves an all expenses stay in a sunny destination for a well tended field while the authorities do their investigation and cleanup.

Covered Registration
 

When visiting the accident site today, I noticed that the aircraft's registration was intentionally covered with a plastic sheet, as well as its name.
Can any member shed light on what is the point in covering these identification marks?
Thank you.

Just some more stuff
 

Heya folks,

just wanted to add a few more things conc. the accident:
About no one using the overwing exits:
all PAX stayed on board for about half an hour AFTER the LDG!
Crew deemed an EVAC as not necessary.

And about the registration and stuff, here are a few more photos, though don't ask me, I didn't take them:
groups.msn.com/TechnikundFliegen/mucaua.msnw?albumlist=2

Thanks so long, greetings,

~b

Perhaps to prevent hypothermia after vacating the A/C?

I can imagine that pictures with the company name and logo are not the sort of publicity welcomed by the airline involved.

Sirius Flying

Immatriculation marks and airline names are often blanked after an accident because no airline likes to see their name on an aircraft which is not very it is supposed to be.

Of course, we know what happened. But do other people just passing by know about the facts? They might take it as a wrong indication of the safety on that airline.

The aircraft is named Wiener Neustadt; isn’t this the home of the longest grass runway in Europe? Very appropriate?

For those interested in the meteorological conditions during the incident, here are two links for the vertical soundings of 05/00 utc and 05/12 utc.

They were launched in Oberschleissheim, only about 25 km away from the airport.

Conditions didn't change a lot during the first half of the day.

Sounding 05/00 utc

Sounding 05/12 utc

Seems to me, until proven otherwise (by the proper authorities) that the crew handled a difficult situation with good intentions...and really good flying skills.
Hats off to them...absolutely!:ok:

Couldn't agree more 411a :ok:

Anyone know the fate of the aircraft from here?

ES ;)

Austrian TV ORF reports the "ice impact trays were broken".

(german)
http://www.orf.at/040108-69491/index.html

Austrian OTS reports (in german), that the Ice Impact Trays were broken on both engines. These parts were broken off the engine casing, and are designed to protect the engine from damage by ice fragments broken from the fan blades (?). Austrian technicans discussed the attachment system of the ice impact trays with Rolls Royce specialists.
Can anyone tell us more about this item ? And about the anti ice system of RR engines in general and especially on the Fokker ?
Do all transport jet engines have this device ? Or is it just a more simple way to handle icing on smaller jets ?

Saw this on another forum.
Does it sound copacetic? Is there a load control valve that cycles the bleed air loads around the various services - and is it electrically operated (sequenced)? Don't know this airplane at all meself.

<<<IMHO the ice impact trays are a symptom (and not the cause). The cause is more likely to be similar (but not the same) to Air Florida's 737 predicament (false EPR generated by icing-over of the P2 probes in both engines). In Air Florida's case they had the power but a misleading false indication. In the F-70 accident it's likely that:

a. Icing over of P1 or P2 air sensors might have caused a very low idle, and robbed the Tay engines of their acceleration - or more likely

b. the load control valve for the wing/tail anti-ice system stuck (instead of cycling) and allowed too much bleed air to be sucked away - thus robbing the engine inlet intake anti-icing of heat (which in turn would have allowed a build-up/choking of the engine intakes in the severe icing conditions - generated a low idle RPM and denied acceleration to a higher RPM).

Similar to the BAe146 rollback except that here the Tays were being denied intake lip hot air and so were choking up with ice (as well as being excessively robbed of bleed air). If it had been just one engine that got stuck at idle you'd think that a bleed-air valve had stuck open. But with both engines, you have to look at a common fault condition - and that's why I mention the in-fuselage load control valve that apportions air (and cycles it between all the pneumatic services).>>>

Just like to add that the pilots of the aircraft did an amazing job in the conditions. How many times have you seen an aircraft land in a field and remain intact, without even a ripple or crack showing, not catching fire or killing everyone on board? not many. All my praise for these top guys.

Hats off to all crew great job!

A well-done to the crew, recovering from whatever caused the terrible situation, even more so if in limited visibility. :D

I found out last night that a friend of mine and his sister were onboard this flight. Here are a few things that he told me:

At around 14,000 ft, the engines became choppy, you could also feel the smell of smoke in the cabin.

The engine power was significantly reduced for the remaining airborne time. They didn´t died.

About 10 seconds before the touchdown, the pilots turned off the engines and they shouted mayday over the PA system.

The aircraft came to a halt very quickly.

Most of the pax thought that they were at the airport. When they found out what had happened, people started crying.

The pax remained inside the aircraft as it was deemed that there was no risk of fire.

It took about half an hour before they left the aircraft. Thats when the rescue services arrived.

/fritzi

Fritzi, your English is very good but I doubt if the crew shouted mayday on the PA 10 seconds before impact. More than likely it was "brace, brace" or whatever is the equivalent in German?

This has just run on Reuters. Most interesting.


Austrian changes ice plates after Munich jet scare

VIENNA, Jan 9 (Reuters) - Austrian Airlines is changing the Rolls-Royce-made <RR.L> ice protection equipment on eight of its nine Fokker 70 planes because of doubts over its safety after one such jet made an emergency landing in Munich on Monday.
Austrian <AUAV.VI> said in a statement released on Friday it had decided to change the Rolls-Royce-made equipment, which protects the plane's engines from ice damage, after inspections led to complaints about safety.
The airline has said a preliminary investigation showed that the emergency landing, in which eight people were slightly injured on Monday, was probably caused by so-called "ice impact trays" breaking off.
"New ice protection equipment will be installed by the manufacturer's specialist teams in all engines in which the strength of the ice protection equipment's mounting could not be established beyond doubt," Austrian said in a statement.
"To avoid any risk, the ice protection equipment will be changed on eight aircraft."
Austrian said it had inspected all its Fokker 70 fleet with Rolls-Royce.
"These (inspections) led to complaints," it added, without giving details.
An official investigation into the Munich accident is ongoing.

There is an update from 8th January with flight recorder info on the german accident investigation website www.bfu-web.de.
All those who don't understand german - get a life!

Ok., for the English speaking community: According to BFU`s official statement mentioned above, FDR data proves that the crew, after an ice detection alert upon reaching FL 100, had indeed switched on engine anti-ice and air frame anti-ice. 6 minutes later engine vibrations became noticeable and increased considerably, 4 minutes later engine power became insufficient and an emergency landing was initiated. Broken ice impact trays were later found in both engines, causes to be further investigated.

(edited for spelling)

Have they grounded the remaining F-70s, or imposed a "do not operate in icing conditions" policy until the mods are done?

I don't agree with the readers ot this topic who praise the crew, I think they made a major b@lls up:
-there was a SIGMET warning of moderate to severe icing in their arrival TMA
-it was snowing at their destination
-they didn't preempt ice accumulation removal by earlier selection of anti-ice systems
-they waited until the (notoriously unreliable) ice warning activated before reacting
-they flew level at FL100 for 6 minutes in moderate to severe icing conditions
-this means that they cocked up their descent planning by nearly 30 miles
-yes I know that there are altitude constraints inbound to Munich but severe weather conditions demand decisive action
-they did not follow the correct procedure for engine vibration warnings in icing conditions
-they did not order an evacuation following a crash landing with obvious structural damage (gear ripped off with probable fuel tank damage)

Hot Dog,

Im just stating what he told me, I am not stating that everything he told me is 100% correct.

/fritzi


PS: The reason why my english is so good is because I went to the american school here in vienna for 13 years (K-12), from which I graduated in May. However, Swedish is my mother tounge, then comes English, then German, then French.

fritzi,
Don't fret about the comments of others regarding proficiency in written english.
Have personally spent nearly my entire flying career overseas, many times in non-english speaking countries, yet found the locals always pleased to help with my rather poor foreign language.
Picked up some working thai/arabic/farsi along the way but always realized that the locals were always better at english than I was at the local lingo.

Regarding icing, have done a lot of First Officer line training in heavy jets, and have always advised these guys to get the ice protection on early least problems are found later.
Say for example one engine anti-ice bleed valve decided to go on holiday, and not open when commanded. 'Tis better to find out about this sooner rather than later.

Anyway, whatever the problems with anti-icing, looks to me like the crew did a damn fine job with the off-airport landing.
We should all be so lucky when faced with a similar situation.

moderatar

The praise for the crew is for what appears a wonderful job of getting that aircraft safely down from the predicament that it was in, whatever the cause. Until the full facts are known, no praise or criticism can be apportioned to anyone as to how the situation occurred in the first place.

ES ;)

"@moderatar:
I don't agree with the readers ot this topic who praise the crew, I think they made a major b@lls up:
-there was a SIGMET warning of moderate to severe icing in their arrival TMA
-it was snowing at their destination
-they didn't preempt ice accumulation removal by earlier selection of anti-ice systems
-they waited until the (notoriously unreliable) ice warning activated before reacting
-they flew level at FL100 for 6 minutes in moderate to severe icing conditions
-this means that they cocked up their descent planning by nearly 30 miles
-yes I know that there are altitude constraints inbound to Munich but severe weather conditions demand decisive action
-they did not follow the correct procedure for engine vibration warnings in icing conditions
-they did not order an evacuation following a crash landing with obvious structural damage (gear ripped off with probable fuel tank damage)"

Maybe it is someone who THINKS to know it all before the facts turn up who has the b@lls up??


The reason for the thrust loss was the detachment of the ice impact panels in both engines almost at the same time, the panels turning by about 90 degrees behind the fan blades and acting literally like a thrust reverser inside the engine. So it could as well have happened in plenty VMC. No need to blame the crew about engine anti ice, during special checks ALL F70s except one had complaints about these ice impact trays.

Snowing at destination?
If light snow at more than 2000m visibility should be a reason to stop operation I would have had a few days off this week.

Evacuation? The gear ripped off was the NOSE gear, no main gears involved. No fuel tank damage. But 28 pax without their coats on; send them out in the snow for more than half an hour without any necessity, via slippery overwing exits or a half-extended pax door?

Minimobil:
Of course I'm not suggesting that snow at destination is a reason for cancelling a flight. What I am saying, and here I agree with my learned friend 411a, is that it is good airmanship to anticipate ice accumulation and activate systems in good time.
As for impact tray damage in VMC - what cr@p! Both at the same time? Impossible!
I believe that the sequence was as follows:
The two Fritzis (AUA Nigels) were so involved in discussing the poor industrial relations in Austrian (strikes and walkouts over the last 4 months) that they neglected to look outside and check for airframe icing. Or maybe they were immersed in one of the monster approach briefings that they learned from their former Swiss masters?
The F70 wing is a known ice accumulator, that's why black stripes are painted at 2/3 span so that it can be seen more easily.
When Kurka and Turk finally woke up to the danger it was too late. Application of wing anti-ice sent lumps of ice into the engines, permanently damaging them, a similar situation to the SAS accident in Arlanda.
I maintain that not to order a passenger evacuation after a crash landing is crass incompetence.

Don't you like Austrians then Moderatar? AUA not give you a job? Your speculation may, however, not be far from the truth!

Modaratar... What a clever guy you are, you do everything perfectly and the others are just sh...

OK then , for your information our company flying F100 equiped whith -620 engines have already experienced two severe engine damage due to these ice pad getting loose and beeing ingested by the engine.

IN BOTH CASES THIS WAS IN CLEAR SKY, NOT USING ANTI-ICING.

I think the crew did a perfect job managing to land this aircraft in a field, they were very unlucky that both engines developped the same problem at the same time.

But What to say about ROLLS ROYCE who was perfectly aware of the problem and did nothing to cure it ? the first engine problem in our company dating more than 2 years and apparently we are the only airline applying specific checks on this part of the engine.

@Baron rouge:
I agree, thanks

@moderatar:
luckily the investigation will not include arrogant postings like Yours.
Unfortunately I am not allowed to send You a certain picture of the engines; one that tells You all if You still believe it was NOT the disintegrated ice impact trays which led to such a severe thrustloss.

About the evacuation: You would send the pax out in the snow when there is no sign of fire, smoke, sparks? With no suspected rupture of the fuselage and wings?
Preferably via the wet and slippery overwing exits, as the pax door would not extend fully?

Just for information:
Both engines did not develop the problem at the same time. The second engine lost power due to ingested "ice prevention tray" at less than 6DME. After this they could not stay on the glidepath and dropped out of the clouds into the snowy field.
Up to 6NM final it looked just like a single engine ILS approach, nobody suspected the second engine to generate the same problem as the first one.

Excuse my ignorance. What exactly are the ice trays and where are they?

ManaAdaSystem,

yas, according to this: http://www.flygtorget.se/nyheter/nyh...D=1850&KatID=1
Austrian grounded their F70 fleet. For the few of you who dosn't understand swedish, here is a translation:

"According to AUA, problems regarding the antiice systems have been found. Ice damage in the engine have been found (not my words) to be the cause of the forced landing. The remaining eight F70 have now been grounded, the Rolls Royce engines are being inspected and the engine ice protection systems are being replaced. Estimated time for the process is one week."

/FS

this is what Bundesstelle für Flugunfalluntersuchung mentioned on their site:

"Zeitgleich mit dem Erreichen der Flugfläche 100 sprach die Eiswarnanlage (Ice Detection) des Flugzeugs an. Die Besatzung schaltete daraufhin die Triebwerksenteisung (Engine Anti-Ice) und die Zellenenteisung (Air Frame Anti-Ice) ein. Die Auswertung der Flugschreiberaufzeichnung bestätigt, dass die Eiswarnanlage angesprochen hatte und die Triebwerksenteisung sowie die Zellenenteisung von der Besatzung eingeschaltet worden war.

Sechs Minuten nach dem Erreichen der Flugfläche 100 kam es zu Triebwerksschwingungen."

So in my opinion the crew immediately switched on the de-icing and it took 6 minutes after reaching FL100 before the engine vibrations (especially the RH) started.

"zeitgleich mit dem Erreichen der Flugfläche 100 sprach die Eiswarnanlage (ice detection) an"

The ice detection warning sounded simultaneously (zeitgleich) with (the aircraft's) arrival in FL100.

(Translation note - "erreichen" is to reach, attain or arrive at, "das Erreichen" is the noun form. Arrival sounds weird in this sense, but "attaining" or "reaching" sounds like climbing in English)

"Die Besatzung schaltete daraufhin die Triebwerkenteisung und die Zellenenteisung ein."

The crew switched on engine and airframe anti-ice immediately after the warning.

(Translation note - daraufhin means "immediately afterwards" or "at that moment" but has a sense of causality. In this sense it suggests to me that they switched on the anti-ice immediately after the warning, but the German is a touch ambiguous - "sofort nach" might have been clearer if that was what was meant, or "unmittelbar nach".)

"Die Auswertung der Flugschreiberaufzeichnung bestätigt, dass die Eiswarnanlage angesprochen hat und die Triebwerksenteisung sowie die Zellenenteisung von der Besatzung eingeschaltet worden war."

Straightforward except for the passive construction. "Examination of the flight data recordings confirms (bestätigen - to confirm) that the ice detection warning sounded and that both the engine anti-ice and the airframe anti-ice were switched on by the crew."

"Sechs Minuten nach dem Erreichen der Flugfläche 100 kam es zu Triebwerkschwingungen."

6 minutes after (the aircraft) reached FL100, engine vibration developed.

Ice Impact Trays
 

http://www.iasa-intl.com/imagery/72407_i.jpg
.

Ice Impact Trays in place
.
http://www.iasa-intl.com/imagery/cafuwn79.jpg
.
Ice Impact Trays displaced

Please correct me if I am wrong, as it is a while since I flew the Fokker 100, but the ice detection warning on the aircraft is a 'late' warning for ice build up on the wings/tailplane. In other words, in normal operations, the wing/tail de-ice should already have been switched on. I seem to remember that the engine anti-ice is selected on at 5 degrees C or below in moist air and certainly doesn't rely on the ice detection warning as a reminder to activate it.

What I am trying to say is that, given the conditions that morning, the engine anti-ice should have been selected on for most of the descent and the wing/tail anti-ice selected shortly before the ice warning.

Crew did an excellent job putting it down in one piece once the second engine lost power.