Interesting CHIRP Question!!

[girtbar]

Has anyone recently read the latest CHIRP Newsletter (issue 33)?

Theres a link to the newsletter below and also a picture that was published within the newsletter.

My jaw was on the floor reading it and wondered what other Cabin Crew think about this situation?

Most of us I would have thought would be savvy enough to know that any sort of ice/snow/slush on the wings is a no go, esp as, we as crew have a slightly bizzare love of Air Crash Investigation shows!!

I know training can vary airline to airline, but are crews educated on wing contamination?

I have been on two flights where we have had to notify the F/D that there was either ice build up or that the De-Icing team had failed to de-ice one whole side of the a/c. On both occasions the F/D where fairly flippant believing that the De-Icing teams had done their job (with out them visually checking!!) or there was little cause for concern. Thankfully we have a reasonably open culture at our airline and on the Cabin Crews instance made the F/D came back into the cabin to visually check the wings.....on both times the sheepish looking FO apologised and got the De-Icing teams back.

What would you do as crew if you had seen the same in the picture below?



http://www.chirp.co.uk/downloads/CCFB/CCFB33.pdf


http://photos-b.ak.fbcdn.net/hphotos-ak-snc3/hs021.snc3/10855_173982466626_561056626_3327642_3295091_n.jpg

[Glamgirl]

I would have gone straight to the flight deck to inform the Captain. If he/she didn't take it seriously (highly unlikely in my co), I would just refuse to call in the "cabin secure". I don't mean this in a rude way, but it would be the only way if the Flight Crew refused to come and have a look.

I read the CHIRP report as well, and I found it very unprofessional of the CC in question.

Gg

[Alycidon]

This icing is (mainly) inside the black overwing non environmental icing demarkation in which Boeing permit overwing ice on takeoff due to cold soaked fuel in the fuel tanks just below the skin of the wing.

It may have accumulated after taxi commenced and possibly in the dark and within holdover time limits.

It also looks like they got airborne without any major incident!

On they other hand, they may be cowboys....who knows?

[TURIN]

This icing is (mainly) inside the black overwing non environmental icing demarkation in which Boeing permit overwing ice on takeoff due to cold soaked fuel in the fuel tanks just below the skin of the wing.


Come again?

Boeing may permit it but I don't think the FAA or CAA do.

NTSB Report (http://www.ntsb.gov/pressrel/2004/041229.htm)

[Re-Heat]

No, no, no!!

Alycidon - you confuse clear cold-soaked fuel frost with snow that has not been cleared!

http://www.smartcockpit.com/data/pdfs/plane/boeing/B737/instructor/B737-Cold_Soak_Fuel_Frost.pdf

Snow buildup is never permissible on the flying surfaces. Look at the photos in the Boeing presentation.

[4468]

Alycidon

I see you're back at Barrow Hill after your summer hols! :ok:

[A and C]

As a Captain I would be most disapointed if the cabin crew did not tell me if they had any doubts about the state of the aircraft de-icing, after all they have a better view if the wings than I do!

[Alycidon]

I was just pointing out how the fresh snow got there... it would stick better to CSFF.

Barrow Hill is a good place for a nightstop!!

For a type 5 at least!

[flyinspanner]

Clean wing policy. end of.
I would let the guys know we have a serious condition.
I've had nothing but support and thanks in same situations in the past.:ok:

[I Just Drive]

You guys should always tell us. ANY crew that don't listen or just dismiss you are ars***es. If you told me, id go look for sure. No reason not to.

Don't be put off by F/D rushing you.

[WASALOADIE]

How long before another accident like this?

This Day in History 1982: Plane crashes into Potomac (http://www.history.com/this-day-in-history.do?action=Article&id=52887)

1982 - Air Florida - Potomac River

[Mornington Crescent]

Alycidon

It is a little while since I opened a Boeing manual.

When I last did - NO snow or ice was permitted on the UPPER surface of the wings. But soft spongy ice caused by cold fuel on the LOWER surface of the wing was permitted.

I would be surprised if Boeing have changed that statement. However, if that is the case could you give a reference?

MC

[lowcostdolly]

Wasaloadie......absolutely!! I was thinking I must be the only CC on here old enough to remember the Potamac tradegy.

I was staggered when I saw this photograph.....it was taken in flight. How on earth did this plane get airborne without incident?

What would I do if I saw something like this.......hotfoot it into the F/D PDQ. On the few occasions I have had too because I've had a concern about anything to do with the operational safety of the flight I have only ever found the Guys receptive and they will investigate.

I believe that is why we do joint CRM training which also incorporates ice awareness/effective communication between all ranks of crew etc etc......things that on the surface seems to have passed the operating SCCM of this flight by if she did not respond to the pax concerns and pass them on. Lets hope that if she/he is still working for this company she has been re-trained.

If she/he did report this to the F/D as her reported response to the pax indicates ("the captain says it's OK") that then raises questions re the CRM culture within that company or maybe just on that flight that day.

[A37575]

Colleague of mine often flies into China and on countless occasions has seen local big jets taking off with ample snow on top of the wings yet they don't crash. This suggests that snow on the wings is not always fatal. I presume it depends on a complicated combination of type of wing design, amount and texture of the contamination, airspeed at VR and maybe other factors.

Witnesses have also described a similar mindset of the crews of these aircraft that happily blast off into close-in thunderstorms while others decide it is more prudent to wait on the ground until the storm has gone through. Yet the aircraft that take the risk of going straight into CB after take off always seem to get away with it. Good Karma, maybe?

[lowcostdolly]

A37575.....Good Karma I would agree, certainly in this case!

Thanks for explaining some of the other factors considered by the F/D :ok:

What happens in China should probably stay in China though.....

[Dit]

Well the wing will almost certainly still fly at a high enough speed with snow on it, but that is missing the point. The reason it's dangerous is because the wing produces less lift, which means at lower speed (when you tend to be close to the ground ie TO and Landing) the wing may be stalled when your performance figures say it isn't.

Adding knots to Vr and Vfly may solve this, but how much do you add? Where did those numbers come from? And more importantly; is it safe AND legal?

[Alycidon]

I Quote....

"Takeoff with light coatings of cold-soaked fuel frost on upper wing
surfaces is allowable, provided the following conditions are met:
• the frost on the upper surface is less than 1/16 inch (1.5 mm)
in thickness
• the extent of the frost is similar on both wings
• the frost is on or between the black lines defining the
allowable cold-soaked fuel frost area (see figure) with no ice
or frost on the leading edges or control surfaces
• the ambient air temperature is above freezing (0°C, 32°F)
• there is no precipitation or visible moisture (rain, snow, drizzle
or fog with less than 1 mile visibility, etc.)"

from a Boeing Manual.

The picture shows that the icing in question does not meet the above criteria and it is a little disappointing to say the least that the crew did not de ice.

The effect of fresh snow falling on the "allowable area" would cause it to stick more to this area, hence the limitation above " no precipitation etc.." which was overlooked by the crew it would seem.

Best to keep it simple....

[Mornington Crescent]

Alycidon

Thank you for that. How times have changed!

MC

[moosp]

Girt Bar thank you for that image. As a pilot it tells me a lot about other pilots who are not doing their job properly.

The wing looks like a 737 series. Anybody know what type the aircraft involved was?

Boeing have done a lot of studies recently sticking expanded polystyrene blocks onto the upper surface of a wing to simulate snow build up. They had observed that certain operators of Boeing aircraft around the world have survived for years after taking off with snow on the upper surfaces of the wing, which we thought, as pilots anyway, would lead to disaster.

I understand that it is type specific. For instance the 737 is more critical, and can have big problems with even light snow on the upper surface of the wing, especially if it is not symmetrical whereas the 747 series is less prone to lift loss with such contamination.

From my point of view, I would really have appreciated one of the cabin crew telling me about that wing in the photo. I would have got de-iced.

[FlyingOfficerKite]

Hi folks

Judging by the altitude of the aircraft it is more likely this icing has been caused by the aeroplane passing through moist air with cold soaked fuel tanks.

The fuel (and therefore the surface of the wing) would accumulate ice if it came in contact with any moisture in the atmosphere.

The ice appears to cover the area of the fuel tanks (that is, non at the wingtips).

Usually this melts prior to landing, but not always. I've arrived on the ground in Spain, for example, with the upper surfaces of the wings having ice still evident. This melts in the heat on the ground during turnaround, however there would be no chance of departing if any ice remained.

I should hope the cabin crew would point icing like this out as if it did remain on the wings prior to landing then there would be performance issues.

Good CRM is to be commended and I hope all pilots would appreciate a word from the cabin about this or any other suspected problem.

KR

FOK :)

[lowcostdolly]

FOK or indeed any pilot can I just ask a question as this thread is actually giving me a much better insight into ice awareness as an SCCM because the F/D are posting.

Assuming that what is photographed was not evident on take off (the Chirp poster says it was) if I came to you prior to landing with my concerns as photographed what could the Pilots do to sort out the performance issues you state? Would we be in danger on descent/landing with ice on the wing?

Sorry if I look stupid to the F/D here but as far as I know and am taught ice on the wing is not good and needs to be flagged up. If we have got as far as the situation photographed in flight what implications could this have on landing?

[FlyingOfficerKite]

lowcostdolly

I would never consider a question from the cabin crew to be 'stupid' - in fact most pilots appreciate interest being shown. Particularly important in respect of safety issues.

I don't know the history of the photograph, but that amount of ice on the wings would pose serious issues if present on the approach and landing.

The amount I have come across has been no more than a frost-like covering on landing.

My advice would be to report ANYTHING you're not happy with to the flight deck - which is the basis of all good CRM in any event.

That crash of a B737 into the Potomac River a few years ago (mentioned above) was caused, amongst other things, by snow on the wings at take-off - and at least one member of the cabin crew had seen it (sorry if you know that already as it's a common example used during SEP training, as you're no doubt aware). I'll never forget the first time I saw the video of that man diving in to rescue the stewardess - brings tears to your eyes!

Better safe than sorry!

What you would do in that situation is a very good question. It would be difficult to dislodge quickly as only the leading edges of the wings having a de-/anti-icing capability. The fuel can get very cold at cruising altitude, particularly over a period of time, and this causes the ice to form if the aircraft flys through cloud. I've never come across anything like this forming in flight where it wasn't present on the ground (others in colder climes may have?). It would be a serious issue and if the destination was cold. Although the speed of the aircraft through the air causes some heating, it is unlikely to be removed if present during the descent. All that would be available would be either to hold (if in warm air and subject to fuel available) or to increase the approach speed (and therefore the lift available), but there are no tables available to the pilot to calculate the performance reduction/performance required in the QRH (the book the pilot uses to manually calculate performance).

All this proves one thing - ice or snow on the wings, particularly at departure, is a BAD THING!

KR

FOK :)

[Dit]

Basically I would fly the approach at a higher speed so the wing was further from the stall speed, which may now be higher than it should be due to the snow on the wing. I don't know of any Boeing advice or performance figures for this situation (for my a/c or any other) so personally I would add the maximum allowable increase to the speed, double check the landing distance required at the increased speed and the amount available, then fly a normal approach.

[deeceethree]

For those who want to read the full available story behind this, it is in CHIRP Air Transport Feedback No. 92, in PDF format, here

CHIRP (http://www.chirp.co.uk/feedback-list.asp?fb=AT)

Starts on page 11 under 'Cabin Crew Reports'.

[Clandestino]

Colleague of mine often flies into China and on countless occasions has seen local big jets taking off with ample snow on top of the wings yet they don't crash. This suggests that snow on the wings is not always fatal. I presume it depends on a complicated combination of type of wing design, amount and texture of the contamination, airspeed at VR and maybe other factors.


Boeing have done a lot of studies recently sticking expanded polystyrene blocks onto the upper surface of a wing to simulate snow build up. They had observed that certain operators of Boeing aircraft around the world have survived for years after taking off with snow on the upper surfaces of the wing, which we thought, as pilots anyway, would lead to disaster.

I really have to borrow the phrase from EK Gann's masterpiece. (http://en.wikipedia.org/wiki/Fate_Is_the_Hunter) I'll just rephrase it a bit:

The trouble with most pilots is that you are spoiled. And lazy. You have never taken the trouble to learn aerodynamics and statistics properly.

Ideally, minimum take-off safety speed (V2) clean wing at take off gives you 20% stall speed margin which roughly equates to taking off with 69.4% of theoretical maximum possible lift. More realistic figures are 13% and 78.3%, respectively (that's where Vs1g comes from). Now if you take-off with ice or snow contaminated wing, not a single person in the world has a vaguest notion of how much did you degrade those margins - "complicated combination of type of wing design, amount and texture of the contamination, airspeed at VR and maybe other factors" notwithstanding. As long as you have 0.1% of lift to spare, you live - most likely fat, dumb and happy. If you get short by 0.1%, your survival is far from being guaranteed.

Taking off with ice on the wings does not necessarily kill you, it merely reduces your chances of having mishap at T/O down to unacceptable level, from one in a billion to one in a... well it's impossible to calculate for each specific take-off but it can easily get into one in a ten. Most of the safety related items work the same way; they don't kill you outright, they merely increase your chance of getting killed. As a pilot, you can make successful ( defined as being completed without major incident or accident) flight while being drunk, while having hangover, while flying fatigued, by making ILs approach with CAT1 aeroplane, on CAT2 ILS, down to CAT 3 minimum, yet your chances of getting killed would be so severely increased that given time, there will be a day on which lady Luck looks the other way and there's smoking hole and a few funerals to be arranged.

Learn statistics and learn them well - it's good vaccine against acquiring invulnerability attitude through repeatedly breaking the rules.

Boeing recommendation is at odds with many a local aviation authority rulings. No aeroplane registered in my country is allowed to take off with any ice or snow on the upper wing surface, no matter what messieurs Boeing, Airbus, Tupolev, Cessna, Bombardier, Cirrus or whoever say. Wing's upper surface is the stupidest place in known universe to save few bucks on glycol.

Chances are that Air Florida crew would have got away with holdover expired but EPR probe unobstructed. Or within holdover time but with reduced thrust as a consequence of EPR probe frozen over. Now we all know that "God! Look at that thing!" callout is reason enough for rejected take-off.

Judging by the altitude of the aircraft it is more likely this icing has been caused by the aeroplane passing through moist air with cold soaked fuel tanks.

No way. Once you're past 100 kt, nothing can freeze behind maximum curvature of the wing. No cloud, no fog, no snow, no freezing rain, nothing. Supercooled large droplets can occasionally refreeze way beyond leading edge, but even they can't move past first quarter of the aerofoil. Any and every contamination behind quarter of the wing chord is ground acquired.

Clandestino, latent flight attendant.
Compliant with the last point. (http://cabincrewblog.com/2007/08/you-know-youre-flight-attendant-if.html)

[TURIN]

I Quote....

"Takeoff with light coatings of cold-soaked fuel frost on upper wing
surfaces is allowable, provided the following conditions are met:
• the frost on the upper surface is less than 1/16 inch (1.5 mm)
in thickness
• the extent of the frost is similar on both wings
• the frost is on or between the black lines defining the
allowable cold-soaked fuel frost area (see figure) with no ice
or frost on the leading edges or control surfaces
• the ambient air temperature is above freezing (0°C, 32°F)
• there is no precipitation or visible moisture (rain, snow, drizzle
or fog with less than 1 mile visibility, etc.)"

from a Boeing Manual.



Don't give a monkeys what Boeing say.

CAA/FAA say otherwise as does my employers de-icing manual.

Ice on upper surface = nogo. De-ice. End of.

[DHC6tropics]

The picture looks like a photoshopped fake to me

[I Just Drive]

Definately not formed in flight. They got airborne with that for sure. Easily done id say too. Walk around done in the dark, under wing ice hard to spot, forgets to look at top of wing. Leading edges all clear. Launch.

There but for the grace of god go I.

[Basil]

Turin is correct.
NO ICE OR SNOW OR FROST AT ALL on UPPER surface of wing whether caused by precipitation or cold fuel.
The UNDERSIDE of the tailplane/stabiliser should be clean.

That photograph, if genuine, is absolutely outrageous!

Since I usually fly BA, it's unlikely that I'll ever have to take 'direct action' however I did, some years ago, notice some frozen water droplets on another operator's wing. I was sure they were going to de-ice off stand - they weren't :*

[RampTramp]

EASA state -
Quote;
A pilot shall not take off in an aircraft that has:
frost, snow, slush or ice on any propeller, windshield or power plant installation or on airspeed,
altimeter, rate of climb or flight altitude instrument systems;
snow, slush or ice on the wings or stabilisers or control surfaces, in gaps between the airframe and
control surfaces, or in gaps between control surfaces and control tabs, or any frost on the upper
surfaces of wings or stabilisers or control surfaces. For this reason a contamination check of the
aircraft surfaces shall be performed prior to departure.
Unquote.

There doesn't seem much room for argument there!

RT

[BALLSOUT]

Shame on CHIRP and shame on the individual that has started this with a complete work of fiction.
If you look at this photograph closely you can see it is a complete fake!.
CHIRP should have looked at this more carefully before taking it up.
All involved should get a grip, and I hope CHIRP have another look at this and take the appropriate action against the individual who thinks it was a good idea.

[flapsforty]

Hi BALLSOUT,
I see from your profile that you´re a 737 Capt. So no doubt you have more knowledge about this matter than most of us here on the CC forum.
Contamination is something we do get training in, in fact it´s one of the spearpoints of this year´s SEP recurrent at my mob. We reviewed the Potomac accident already mentioned on this thread.

But even after having spent 5 years on the 737 in the past and regular training on contamination, I can´t say I´d be confident to make a definitive statement about wing contamination one way or anther.
See ice/snow on wing => alert pilots
If you´d care to explain a bit more about why you believe this pic is a fake, I´d be grateful.

[BALLSOUT]

Hi Flapsforty, My statement is not based on my knowlege of the 737, I simply downloaed the photograph and zoomed in on it and it is clearly a fake. You can see that the wing has been cut out of another photograph and pasted into the airborne view. I am confident that this is a prank that CHIRP should have worked out before going any further with it. I expect this will leave a lot of people with egg on face.
If I were to use any of my technical knowlege or experience. I would say if the wing did in fact have this much snow on it, the aircraft would be unlikely to even get off the ground. If it did, once it had a few hundred knots of air over it, the snow would probably have come off. It would certainly have started to come off in large chunks.
Snow and ice on aircraft wings is a serious problem that has killed many people and no doubt will kill many more. I am 100% convinced however, that this is in fact just a sick prank!
For the record, If I was a passenger on an aircraft with this much snow on the wings. If the crew didn't have it removed I would stand up and insist it be done. If they were unwilling to listen to me I would remain on my feet preventing the cabin from being secure until they either offloaded me or de-iced the aircraft!

[737]

It was a Ryanair 737-800.

[FlyingOfficerKite]

I've just received CHIRP through the post today.

Having read the article, some of my previous comments are not applicable.

I'm not sure about the article being fake, particularly if CHIRP have contacted the operator, as stated in the article. If it is a fake it would show a lack of due diligence on the part of CHIRP and will no doubt result in an appropriate response in due course if the operator has indeed been wrongly accused. I find this hard to believe.

The pattern of snow on the wings suggests it is in the region of the fuel tanks, with the leading edge (de-iced) and wing tip not being covered.

If it is a bona fide report, then it shows the degree of contamination which a B737 will tolerate without falling out of the sky - which I trust will enable pilots to gain an insight into the issue rather than think if they depart with snow or ice on the wings all is not lost!!!

KR

FOK

[The Real Slim Shady]

737

It was a Ryanair 737-800

Your logic being.........?

[lowcostdolly]

FOK thank you :ok: Will carry on as normal then.....see ice= get advice!! Our drivers will always look at anything untoward ;)

I know I'm being boring here but can I just ask if you guys know something about CHIRP that I don't?

Reporting through CHIRP is supposed to guarentee anonimity yet we have somebody on here posting that this was an FR 737-800. How would 737 know? All the FR 737's I've seen around have huge winglets with their logo on. Do CHIRP let these things slip?

Ballsout if this is a fake I didn't see it. I did however think it was unbelievable the plane took off without incident. That was only based on my memories of Potomac and the very limited ice awareness training given to CC during CRM. I know nothing of the physics of this and the F/D posting on here have given me greater insight.

CHIRP guarentee they will destroy all personal records of the person giving the report once the investigation is concluded and their posts indicates it was. How then are they supposed to take action against anyone if this is indeed a fake? Your post indicates they can do this.

I ask because if ever, God forbid, I did have a safety concern not adressed by the F/D I would go through CHIRP because I would want my anonimity assured. My company's management make all the right noises re safety reporting but I know what happened to a friend of mine in respect of doing this openly. It would have been CHIRP for me until I saw these posts.

Clarification appreciated :)

[FlyingOfficerKite]

lowcostdolly

You're welcome - I'm pleased you consider the above F/D comments have been useful.

In so far as anonymity of the CHIRP reports is concerned, I am looking at my copy as I type.

The back page, as you are aware, states amongst other things that: '1. Your personal details are required only to enable us to contact you for further details about any part of your report...'

It is totally confidential as far as I am aware - it wouldn't work otherwise. The article does, however, mention at the beginning that the report 'has also been published in the Autumn issue of Cabin Crew FEEDBACK to raise crew awareness.' I don't know what terms and conditions are attached to that publication.

All I would say is this is such a serious incident that the matter is being treated with an appropriate degree of interest by CHIRP in that 'The reporter's concern, together with photographic evidence, was forwarded to the management of the operator concerned'. However it is more likely that the incident became 'common knowledge' among the cabin crew and flight deck and this is how the story was 'leaked'.

I cannot believe that any pilot seeing that photograph would be anything other than appalled and it beggars belief if the 'facts' concerning the article are correct.

The whole point of confidential reporting is that it enables safety matters to be addressing without the input and possible consequences of management finding out and taking action against the employee.

This very fear, present in most employees, unfortunately shows that commercial and corporate concerns take precedence over safety matters in reality no matter what hype PR departments and management might 'spin' in their advertising and publications. Safety is a dirty word, it costs money and a perceived lack of it has a profound affect on the perception of the airline with the travelling public.

That statement might be seen as controversial but ask yourself the question - when was the last time airlines VOLUNTARILY incorporated a safety feature UNILATERALLY into their own aircraft to enhance safety. Never as far as I am aware.

Yes we have bullet-proof doors, oxygen masks, life-jackets and smoke hoods for the crew. Which airline was it that first introduced these items and advertised them as a selling point to their customers? No one - the airlines were driven kicking and screaming by the regulatory authorities to install them as a consequence, in many cases, of an accident. In fact the majority of safety features and SOPs in modern airliners can be traced back to a particular incident or accident. Boeing have, within the past few years, revised their Checklists for the B737 because of the problems with pilots forgetting to manage the pressurisation systems correctly. Safety learnt by experience.

No wonder then that the prospect of openly reporting such a matter to management is likely to result in a less than enthusiastic response.

Think of duty hours - do airlines accept that crews get fatigued and roster less than the maximum hours - of course not, they use CAP371 to its limit. The airline that has reportedly been involved in this incident is famous for cutting costs.

Long live CHIRP and NEVER consider holding back on a report if the matter warrants such a article. That's how we and others learn and survive.

For my part I discontinued a duty once because I felt too fatigued. I had the desired rest but was too tired. I asked for a relief crew to take my place after the first rotation. I didn't report 'fatigue' just a 'tummy bug' because I knew how management would react (as we all do). As cabin crew and pilots all know it's the management who should be on CRM and SEP courses - maybe then they'd have more idea about the consequences of their actions.

It'll never happen because MONEY rules OK.

Keep reporting. Stay professional!

KR

FOK

[BALLSOUT]

lowcostdolly, I think FlyingOfficerKyte has covered all that you asked about.
I expect we will just have to wait for a while to see what comes of it. No doubt it will eventually find it's way onto PPRUNE if it was fake, who's aircraft it is, and the outcome of any enquiry.
The down side of this is, if in deed it is not a fake. People may decide it's actually ok to fly with a bit of ice on the wings after seeing the photo!

[Yaw String]

I think that the apparent (curved) loaded wing and appearence of a flash reflection from the cabin window argue against a fake. The wing does appear to be in flight, therefore contraindicating the need to cut and paste it from a different photo. If the snow on the surface has been cut and pasted from a different photo, it is a very clever fit!
The maxim here for all CC to think about..if it looks different, communicate with the pilots. Never ever seen this in flight..not even on a DC3, that fly's slow enough for sparrows to hold a tea party on the wing!
:ok:

[CD]

In so far as anonymity of the CHIRP reports is concerned, I am looking at my copy as I type.

The back page, as you are aware, states amongst other things that: '1. Your personal details are required only to enable us to contact you for further details about any part of your report...'

It is totally confidential as far as I am aware - it wouldn't work otherwise. The article does, however, mention at the beginning that the report 'has also been published in the Autumn issue of Cabin Crew FEEDBACK to raise crew awareness.' I don't know what terms and conditions are attached to that publication.
FOK...

All of the CHIRP publications contain the same disclaimer. The program also includes the following overview:

About CHIRP

CHIRP for Aviation = Confidential Human Factors Incident Reporting Programme
CHIRP for Maritime = Confidential Hazardous Incident Reporting Programme

The aim of CHIRP is to contribute to the enhancement of aviation and maritime safety in the UK, by providing a totally independent confidential (not anonymous) reporting system for all individuals employed in or associated with these industries.

CHIRP has been in operation for aviation since 1982. In 1996 the Programme was restructured in the form of a charitable company limited by guarantee to enable it to make a more effective contribution to the resolution of important safety-related issues. This corporate structure was selected in order to provide a totally independent organisation, with management and fiscal responsibilities held by an Independent Board of Trustees. The maritime programme has been operating since July 2003.

CHIRP welcomes safety-related reports from flight crew, air traffic control officers, licensed aircraft maintenance engineers, cabin crew and the General Aviation community and people in the maritime sector, including the shipping industry, fishing industry and leisure users.

Reporters' identities are kept confidential. Personal details are not retained and are returned to the reporter or destroyed on closure of their report. The information provided is made available, with the approval of the reporter, and in a disidentified form to those who can take action to remedy the problem. Important information gained through reports, after being disidentified, is also made as widely as possible, principally through the publications Air Transport FEEDBACK, General Aviation FEEDBACK, Cabin Crew FEEDBACK and Maritime FEEDBACK with the aim of improving safety. standards.

The CHIRP aviation programme complements the Civil Aviation Authority Mandatory Occurrence Reporting scheme. Both aviation and maritime programmes also complement other formal reporting systems operated by many UK organisations, by providing a means by which individuals are able to raise issues of concern without being identified to their peer group, management, or the Regulatory Authority. Anonymous reports are not normally acted upon as they cannot be validated.

CHIRP (http://www.chirp.co.uk/)
CHIRP Air Transport FEEDBACK (http://www.chirp.co.uk/feedback-list.asp?fb=AT)
CHIRP General Aviation FEEDBACK (http://www.chirp.co.uk/feedback-list.asp?fb=GA)
CHIRP Cabin Crew FEEDBACK (http://www.chirp.co.uk/feedback-list.asp?fb=CC)
CHIRP Maritime FEEDBACK (http://www.chirp.co.uk/feedback-list.asp?fb=M)

[FlyingOfficerKite]

CD

Thanks for the info.

KR

FOK

[Bigmouth]

Sure a modern aircraft can fly with a load of contamination on the upper wing surface.

Until you lose an engine.

[A2B Ferry]

Im sure its hypothetical as I am sure either the captain or the F/O would check to ensure that the aircraft was fit for flight

[FJJP]

Like BALLSOUT, and after 37 years of driving various airframes round the world, I would absolutely refuse to get airbourne with ice/snow contamination on any flying surface. Despite what manufacturers say. Maybe in extremis like going to war, but never otherwise...

[bonvol]

In all my years of flying I have never seen a wing with ice like that on it in flight.

The fake photo hypothesis is looking good to me.

Nevertheless, any flight attendant who alerts me to ice anywhere gets a big thumbs up. Any pilot who would dismiss such information out of hand without checking is quite frankly an idiot.

[Juan Tugoh]

Sure a modern aircraft can fly with a load of contamination on the upper wing surface.


Problem with this sort of attitude is that it displays a stunning lack of awareness of what is happening aerodynamically to the wing. Adding snow/contaminant to the wing does several things, of which two are vitally important: a) it adds an undetermined weight to the aircraft, b) it changes the aerodynamic properties of the wing.

So at a critical moment of flight, takeoff, your performance figures are rubbish. You normally rotate at approx 1.2 Vs for the weight and given performance of the wing. So, an unknown amount of weight has been added bringing you closer to Vs, at the same time the wing performance has been degraded at an unknown rate. As you rotate you are asking more of the wing as you increase the AoA, pushing you closer to the stall.

As a wing stalls the centre of pressure/centre of lift moves rapidly forward on the upper surface of the wing causing a pitching up movement, again increasing the AoA. So at the stall you pitch up - you don't know the stall speed due to extra weight and degraded wing performance. And it gets worse - the previously clean and identical (or as close as makes no difference) wings, are now contaminated to differing degrees. So the wings will stall earlier and at differing times. So just at rotate, you raise the nose and stall ONE wing causing a rolling manoeuvre with low airspeed and high AOA - the perfect conditions for spin entry. You won't spin of course but the half flick roll into the concrete is usually terminal.

This is exactly what happened to the biz jet at Brum a few years ago.

If there is contamination on the wing DO NOT GO.

[A2B Ferry]

Its not actually the weight which is the issue as this is negligible in relation to the weight of the fuel burned but the effect on lift, stall speed and increased drag. You are quite right, all performance data is collated and refers to and is applicable to a clean airframe so they do in fact go out of the window. Even a small amount of contamination can cause early airflow separation and ice compared to medium grain sandpaper can increase the drag on an aircraft by 25% and that does make a difference!!. With reference to the Birmingham accident, the aircraft landed and was refuelled. It stood on the apron with a quartering tailwind and the wind blew the hot air from the APU across one of the wings which cleared an ice build up. The decision was made not to de ice and as the aircraft subsequently attempted to rotate, an uncommanded roll occured due to the clean wing genrating more lift than the contaminated wing which due to the aircraft being so close to the ground, the pilot was unable to recover and the result is now in the AAIB records.

If there is cotamination on the aircraft. DE-ICE!!!!!!

[Bigmouth]

Problem with this sort of attitude is that it displays a stunning lack of awareness...:rolleyes:

1-2-go, I apologize for the attempt at sarcasm in my above post. I thought it was fairly obvious, but I guess I was wrong. I will henceforth add the appropriate smilies to avoid misunderstandings.