Austrian Airlines Fokker EMG landing

[sublimaze]

Summary from another thread about what happend:

**A Fokker 70 from Austrian with 35 people on board. The plane was bound for MUC and reported engine problems during approach. the crew did not manage to reach RWY 2L and made a crash landing on a field 2 kilometers from the threshould. according to reports from MUC rescue staff there was only one person with minor injurues. The whole thing happened 08:30 LT.

According to newest information, the crew declared an emergency during approach due to icing on both engines and then crash-landed on an open field.
due to heavy snowfall the emergecy-respone-forces took a while to locate the aircraft. the passengers were evacuated with 4-WD (as the field is quite muddy) to the next road and then by bus to the airports care team.
considered that we have (and had) heavy snowfall, there are some farmhouses and a lot of powerlines in the area, the crew did a perfect job.

Picture

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. **

Before we go into discussion with icing problems, i would like to state that AUA crews have been well trained and informed about operating in icing conditions and i truly cannot believe, that the crew "could forget" things with such importance.

May some Fokker crews comment on the Ice Impact Trays ?

 

[fokkerjet]

According to Fokker......

The aircraft encountered severe icing conditions somewhere on the descent/approach phase......

And, on both engines, the fan case impact panels had come loose and were partially blocking the bypass flow through the outlet guide vanes.

How this relates to the chain of events leading to the accident, and the inability for the engines to achieve their required thrust is being reviewed.

The accident aircraft had 6 larger, modified ice panels installed on both TAY's, the older style ice panels, which are smaller, totalled 36. Not that there are a lot of TAY 650 operators around anymore (UPS 727's and the few F100's at American I would guess) but their ice panels are of the same design as the TAY 620's that are on the F70. I'd guess this would probably include the TAY 611's on Gulfstreams.

 

[sublimaze]

Thanks for the insight.

 

[fokkerjet]

Fokker update

Fokker is now recommending: "Engine anti-icing must be on during all flight operations when the TAT is below +6 degrees down to and including -25 degrees C, irrespective of the presence of visible moisture."

 

[sublimaze]

interesting...

Wonder in which direction the investigation leads: material failure/defect or non-standard procedures/operation and how those panels became loose.

But that's the big question anyways....

 

[fokkerjet]

The time line that Fokker gives: .......reaching FL100, the ice detection alert was activated. The flight crew switched on both the engine and airframe anti-icing systems. Six minutes after reaching FL100, engine vibration was observed. The FDR shows that in particular, RH engine vibrations started and increased in a short time. Four minutes later, the thrust of both engines could not be sufficiently increased any longer. The resulting thrust was insufficient to reach the intended runway.

 

[sublimaze]

Far away, it looks a bit like the SAS accident with the MD-80, but only far away....

Being in serious icing conditions could surely create such vibrations, anti ice being unable to shed off residual ice anymore...

ice detection alert was activated. The flight crew switched on both the engine and airframe anti-icing systems

To me that sounds as they entered these conditions without having the EAI/WAI already activated ? I don't know the exact procedure for the respective Fokker's, but recall that Boeing "recommends" the engagement of WAI/EAI before entering severe icing conditions...but that would be speculation at this time.

But surprise that they apparently found 8 of 9 airplanes having a similar discrepancy.

 

[fokkerjet]

I believe the SAS MD-80 involved clear ice sheets, on top of the wings, being ingested into the engines after lift-off and not a flight into icing conditions. In the SAS case, they FODed (if that's a word) out both engines, but in this case, I don't believe ice was ingested, damaging the fans, but instead it may have shed off the fans and damaging the ice panels behind the fan. What will be interesting to see is what effect going to the larger ice panels had on this accident........maybe bigger / fewer isn't better.

As for Fokker anti-ice procedures, anti-ice (both the engine and/or wing and tail) must be on during all flight operations when icing conditions exist or are anticipated.

 

[enigma]

Re: According to Fokker......

And, on both engines, the fan case impact panels had come loose and were partially blocking the bypass flow through the outlet guide vanes.

Just what are these fan case impact panels?

How this relates to the chain of events leading to the accident, and the inability for the engines to achieve their required thrust is being reviewed.

The accident aircraft had 6 larger, modified ice panels installed on both TAY's, the older style ice panels, which are smaller, totalled 36.

Fokkerjet, could you please give a short explaination of the Engine Anti-Ice system on the Fokker?

I'm familiar with hot inlet lips/guide vanes, etc. Does the Tay use somewhat the same system as the JT8?

thanks,
enigma

 

[fokkerjet]

I can't compare this with, say the JT8, my only experience on jet engines have been on smaller Pratt's or Garretts, or the larger RR Tay 611 and 620and the BMW/RR BR710.

The Rolls engine has no inlet guide vanes, but anti-ice protection is via bleed-air to the nacelle leading edge, the inside of the air intake, and with a rubber tipped spinner that will dislodge any accumlation before it reaches any significant proportions. In theory, as ice accumulates on the spinner, the rudder tip spins in such a manner that it forces ice off of it, into the engine, and then out the back through the bypass.

With regards to the fan case impact panels, I had never heard of these until the accident, further research needs to be done, but I'd assume that they are there to prevent shedding ice from entering the engine core.