De-ing related accidents.

[buzzc152]

Hi

I'm working on a little project and need some examples of accidents in which inadequate (or zero) ground de-icing/anti-icing/contaminated wing was a major factor.
I seem to recall one in the US where an aircraft crashed in to or near a bridge following a takeover with contaminated wings.

Any help appreciated.

[tdracer]

This is the one you're thinking of:

Air Florida Flight 90 - Wikipedia, the free encyclopedia

There have been others, but Air Florida was the big wakeup call.
This one is suspected to be contaminated wing was well, but some believe it was a bomb or other terrorist act.

http://en.wikipedia.org/wiki/Arrow_Air_Flight_1285

[bingofuel]

If I recall, Palm 90 was more to do with inadequate T/O thrust due to iced over engine probes giving higher than actual indicated thrust settings , than a contaminated wing.
Firewalling the thrust levers and it would have probably flown out if it.

More a training issue, engines either work or fail, no one considered the reduced thrust scenario on take off.

[mymymy]

Air Ontario 1363 at Dryden (1989) was subject to judicial inquiry ...
Commissions of Inquiry

[Mad (Flt) Scientist]

In addition to 'Dryden' there was a similar accident at LaGuardia a few years after, USAir405. Thee have been a few others to the Fokkers including in France a few years ago (where everyone walked away, I think). Dryden was probably the 'wake up call' accident as far as ground icing is concerned, the 'clean aircraft concept' more or less started there.

There's also been accidents to the Canadair Challenger - derived aircraft which have been similar: a Challenger 604 at Birmingham in the UK and a CRJ in China, for example.

[mjudk]

Originally Posted by Mad (Flt) Scientist

There's also been accidents to the Canadair Challenger - derived aircraft which have been similar: a Challenger 604 at Birmingham in the UK and a CRJ in China, for example.

This is the UK AAIB report on the Birmingham Challenger. Several recommendations regarding de-icing/clean wings

http://www.aaib.gov.uk/cms_resources...pdf_503172.pdf

[buzzc152]

Many thanks all. Very useful stuff.

[captplaystation]

Having flown the little Fokker for a year, I could have handled the report into this incident myself. . . . . . . . . . .

ASN Aircraft accident Fokker 100 F-GMPG Pau-Uzein Airport (PUF)

[captplaystation]

Any swept wing jet transport with no leading edge devices is very subsceptible to icing. I was lucky that my FK100 Conversion was carried out by an ex Fokker company pilot, who had lost a colleague in a take-off accident (posted below) which (contrary to the report ) he told me was caused by exceeding the hold-over time subsequent to a crew-change due sickness, followed by either no/wrong info, resulting in the new Capt departing with no further de-icing ( & assumedly no tactile check ) .

I had previously flown the DC9-15, but we weren't that paranoid . . . maybe we were just lucky.

He told me straight 100% you MUST be sure you have no ice/frost you MUST do a tactile inspection of the wing before being sure, I believed him, the guys in Pau didn't do the TR with him I guess.



http://aviation-safety.net/database/...?id=19930305-1

[dixi188]

27 December 1991, SAS MD81 at Stockholm due to ice ingestion.

[Skyjob]

Many incidents and history on this subject. There is a very extensive online tutorial course from a Scandinavian outfit raising awareness in the pilot community for those airlines which purchase its content.

Facts and incidents speak louder than coursework.
It is impossible to ignore the many lives lost due to wings, designed to operate under a set of conditions, loosing lift capability due ice accumulation of some form or other.
Furthermore it is impossible to ignore the added weight by airframe icing on a large jet, which would not be taken into account in any performance calculations. (Imagine the weight of a few mm of airframe ice when you realise that the paint using standard 4-mil (0.1016-mm) paint thickness on a jumbo is already ~250kg!)

Fly safe, adhere to clean wing policies, or on certain models their black line philosophy, it's not worth loosing your life over a few liters of deicing fluid.

[aerolearner]

I suggest you to have a look at the modules covering Air Florida, Air Ontario and SAS accidents in the FAA "Lessons Learned from Transport Airplane Accidents" library:
Lessons Learned - Inclement Weather/Icing
You will get a quick but complete overview of the key points related to the accident in a nice format.

[Mad (Flt) Scientist]

Originally Posted by Skyjob

Furthermore it is impossible to ignore the added weight by airframe icing on a large jet, which would not be taken into account in any performance calculations. (Imagine the weight of a few mm of airframe ice when you realise that the paint using standard 4-mil (0.1016-mm) paint thickness on a jumbo is already ~250kg!)

To be honest, the weight of the ice is not the concern, and I wouldn't rank it in the same category at all as the aerodynamic effects.

Firstly, all the weight will do is degrade the performance, a bit. Unless you get unlucky and lose an engine or have some other problem, the performance margins are usually going to be enough to absorb the extra mass.

What weight will not do, but ice on the wing's does directly do, is affect the aerodynamics. The wing will stall earlier, and likely differently to anything that it might have been designed to do. And the margin of the aero changes can be huge -30% in maximum lift isn't out of the range at all.

To illustrate, assuming a smallish airliner with about 1000sqft of area (wings, fuselage, everything) and as takeoff mass in the 30 tone range. Losing 30% of your lift is similar to suddenly weighing 30% more, so that would be 9 tonnes.

9 tonnes of ice, distributed over 1000sqft would be about 4 inches thick, if my maths is right. Snow can be substantially less dense than ice, so you're looking at multiple feet of snow. It's likely that an unaddressed accumulation would be somewhat smaller, perhaps a couple of inches of snow, max, or a thin layer of ice. Chances are, the effect of the mass of the contamination would be 1/10th of any aerodynamic effect.

Completely agree with your sentiment to keep it safe, but to be honest, mass isn't the main problem.

[DaveReidUK]

To illustrate, assuming a smallish airliner with about 1000sqft of area (wings, fuselage, everything) and as takeoff mass in the 30 tone range.

That sounds way out.

A 35-tonne CRJ7, for example, has around 1,500 sq ft of wing surface area alone, then add to that the remainder of the fuselage, empennage, etc.

[ESQU]

I recall KLM Cityhopper having an incident in Turin in 2002 that involved clear ice on the wing and also Macedonian had a hull loss in Skopje in the 90s that was marked down as lack of de-icing.

[Mad (Flt) Scientist]

Originally Posted by DaveReidUK

That sounds way out.

A 35-tonne CRJ7, for example, has around 1,500 sq ft of wing surface area alone, then add to that the remainder of the fuselage, empennage, etc.

Are you counting both sides of the wing i.e. total surface area? (Which might be a useful quantity for drag/skin friction purposes, say) The CRJ700 has a nominal wing area of 760 sqft, and that is the planform area, extended to centreline (so part of it isn't exposed). So there's likely more like 600 sqft actually exposed.

I was actually thinking of the CRJ200, which has about 500sqft of wing area and a 24 tonne MTOW, and rounding numbers off, to not be too specific.

[DaveReidUK]

Yes, I was taking total surface area literally, but I accept your point that if you're talking about stuff falling from the sky, then it's only upper surfaces that are relevant.

Anyway, I agree that the aerodynamic effect of icing is much more of a concern than its weight.

[JammedStab]

Originally Posted by captplaystation

Any swept wing jet transport with no leading edge devices is very subsceptible to icing.
I had previously flown the DC9-15, but we weren't that paranoid . . . maybe we were just lucky.

He told me straight 100% you MUST be sure you have no ice/frost you MUST do a tactile inspection of the wing before being sure, I believed him, the guys in Pau didn't do the TR with him I guess.

You are bang on. By far the biggest danger is for unslatted-swept wing jets. If you look at the long list of jets that have crashed due to wing contamination issues on takeoff, only one had slats...the Air Florida 737. And as someone already mentioned, there was a significant lack of power application in that incident.

Several DC-9's have crashed but only the early versions with no slats. Several CRJ's have crashed but only the 200 version with no slats(and unslatted Challengers with their similar wings).

This phenomenon was specifically mentioned by the NTSB in the La Guardia F-28 accident.

Never fly with frozen contamination on these type of aircraft(unfrozen such as bugs would be of concern as well I suppose). And I would suggest de/anti-icing as a precaution as the temperature approaches freezing if there is moisture on the wing.

Originally Posted by DaveReidUK

Yes, I was taking total surface area literally, but I accept your point that if you're talking about stuff falling from the sky, then it's only upper surfaces that are relevant.

Falling precipitation can contaminate the leading edges under certain circumstances. We were parked into wind once and ended up having to de-ice the front of all the prop blades once(16 blades) when we got wet snow falling(mostly horizontally) in a 30 knot wind as the temperature was decreasing leading to a bunch of ice on the blades and the wing leading edge. I remember that they didn't need to de-ice the top of the wing.

[Mad (Flt) Scientist]

Originally Posted by JammedStab

Never fly with frozen contamination on these [unslatted-swept wing] type of aircraft(unfrozen such as bugs would be of concern as well I suppose).

Never do so with any type of aircraft unless you have some kind of specific approval and are sure of what you are dealing with. While there is a weak correlation with hard wings - think of all the types you didn't mention that fall in the same category - one type being more at risk does not makes others free from risk. Contaminate the slat and leading edge of a slatted type and you will see a large, even alarming, loss of lift capacity and potentially hazardous changes to handling at and near the stall, which might be a lot closer than you expect.

The regulations now in force have introduced massive conservatism for ice, including on takeoff, but practically no aircraft in service today have had to comply to these rules, they predate their effectivity. Until the fleet is totally rolled over, the risk remains, and even the new regs don't allow for an intentional contaminated leading edge on takeoff!

If in doubt, de - ice or don't go.

[MrSnuggles]

27 December 1991, SAS MD81 at Stockholm due to ice ingestion.

Link to the investigation report from the Swedish equivalent of NTSB/ATSB/BEA/BFU/AAIB/etc....

http://www.havkom.se/virtupload/cont.../C1993_57e.pdf