Hoverbover: apologies for getting overheated about snow!!

Tiercel: There are very few, if any 'current' civilian helos that are allowed to fly in icing, and the definition of icing is: flight in visible moisture below 0 degrees celcius (in the UK anyway). This includes snow. That's why I said "do not fly".

CTD: I was based at Shearwater on exchange to 423 sqdn for 3 years in early 80's. Did a couple of cross country's to nanaimo (if I remember the spelling) and stopped en route to do glacier and snow flying. Also flying off frigates from St Johns harbour because the ship was stuck solid in sea ice!!
Were you a mil pilot with the air force too?



------------------
Thermal runaway.

No, I was on the civvie side. Mainly Newfoundland in the 80's, Labrador and the Arctic in the 90's, with a couple of shots over in Asia and Africa to warm up in between :)

As for your 'no flight in visible moisture below 0ºC', good thing we don't have that regulation in Canada, there'd be no point to have helicopters! Excuse my ignorance, but is that applicable even if the aircraft is properly equipped with snow deflectors or the equivalent?

Randy, Tiercel, IHL, you're all from Canada, did you guys know that.....?

------------------
Crash Test Dummies are people, too.

To TC

No appologies needed, There is just SNOW way I want you two to fall out.

regards
hoverbover


[This message has been edited by hoverbover (edited 08 March 2001).]

the regulations don't state what "icing" is, just that you're not supposed to knowingly fly into conditions conducive to it.... 'visible moisture below freezing' is what you learn in training, and I think it is accepted that snow is exempt.

Thomas Coupling,

As a mil pilot I was under the impression that rotor and airframe icing conditions are defined as cloud or fog within the temperature range 0 deg C to 30 deg C true, WHEN THE VISIBILITY IS LESS THAN 1000 METRES. Visibility reduction due to snow alone does not constitute an icing condition.

There are different rules for icing conditions (no go) and for flying in snow (dependent on viz/temperature)

http://www.stopstart.fsnet.co.uk/smilie/wokka.gif

Wow, Ed! What sort of ice forms at 30 C? I take it you mean minus 30?

Yikes !! CTD I don't know the British regs, but if it could be interpreted that way... If we had a reg that could be interpreted that way, very few would be flying during the winter.

On that note, today is moving day and back to the Great White North. Talk to you guys :)

Cheers

Randy_g


Now where the heck did those heater controls go !!!! :)

Ed Winchester: that brings back memories, and yes that was the statement I was looking for (albeit -30 degrees!!). The mil fine tune it to some degree by putting a figure on it (1000m, probably because thats the dividing line between fog and mist?).

However I'm sure the mil also restrict snow to flying in those conditions 'below 500m' do they not?

You failed to mention also that precipitation is also included in the definition. In fact any precip in this range incurs some kind of airframe or engine icing actions. I would suggest that since rain/drizzle is precip, then so too is snow. Wet snow most certainly is.

CTD: My definition of visible moisture is rain / fog / cloud / snow / anything with water molecules in it. Provided you stay away from this then one can fly down to whatever the FLM tells you: -30 degrees for example. So flying around sub zero is a very common practice over here too!! but not in visible moisture, unless that particular model is specially fitted for sub zero flight envelopes (EC155, S76, puma, S61 for example).

[I know that below a very low temp (can't remember offhand I think it's -20 degrees?) one encounters supercooled droplets and yet lower than this: ice crystals, where a/c fly because they have negligible effect on the airframe, but that's not helo territory, I believe!]

Open to scrutiny??

------------------
Thermal runaway.

[This message has been edited by Thomas coupling (edited 09 March 2001).]

Shy Torque,

I'm gonna have to get up early to catch you out!

Tom C,

Close, but no cigar!

"You failed to mention also that precipitation is also included in the definition" (one too many also in there!)

That is because it isn't in the definition. The definition is verbatim.

So, flight in rotor and airframe icing conditions or hail or freezing rain/drizzle is prohibited.

As I said, VISIBILITY REDUCTION DUE TO SNOW ALONE DOES NOT CONSTITUTE AN ICING CONDITION. So we can fly in it.

"However, I'm sure the mil also restrict snow to flying in those conditions 'below 500m', do they not?"

Mate, I have not got a scooby what that question means!

If you mean do we have some restrictions to flying in snow, then yes. Obviously it will be different for each type.

For instance:

Flight in falling snow IS PERMITTED in OAT down to minus 30 deg C subject to the following:

(1)Flight is permitted in falling snow of any severity in OAT colder than minus 4 deg C. Flight must be in VMC and visual contact must be maintained with the ground.

(2)Flight in visibilities of less then 400m in OAT of minus 4 deg C or warmer must be avoided.

Finally, as you rightly suggested, WET SNOW is a hazard, and so, flying in recirculating snow at minus 4 deg C or warmer is kept to the mimimum.

Cheers,

Ed

PS. I'm off to Canada in the near future to fly for three years, so I look forward to flying in real snow, not the 1/2 inch covering which seems to grind this country to a halt!

http://www.stopstart.fsnet.co.uk/smilie/wokka.gif

[This message has been edited by Ed Winchester (edited 09 March 2001).]

To Everyone
Thanks for everyones input so far.
As I started this thread I was unsure of many things, and am learning all the time.

In flight below -10 C OAT airframe icing does not occur, is this correct or is at a fixed wing thing?

In the RFM the heli I fly is cleared for flight in blowing and falling snow,(providing the particle seperator is fitted)
but has no temp ranges.But is not cleared for flight in known icing.So is flying in snow below 0 C greater than3000m vis correct/incorrect.

I am a little confused at to what constitutes icing conditions.Does snow below zero C but greater than 1000m vis constitute icing conditions (just curious not thinking of flying in it)

regards
hoverbover

PS
Posted this just as ED Winchester posted his,hence I hadn't seen his post,very informative.Cheers

Ed Winchester
Have a good time, just dont fall asleep on the way home from the Pub in winter !!!!!


[This message has been edited by hoverbover (edited 09 March 2001).]

Hoverbover,

Put simply, icing conditions are conditions where icing will build up somewhere on your aircraft. Depending on aircraft type it may be the engine intakes or elsewhere on the airframe that is most critical. It isn't possible to generalise too much because each type is different. Icing trials have to be carried out to determine limits / clearances for each type of aircraft.

Ice accretion rate depends on:

Temperature: Above OATs of zero C there is unlikely to be airframe ice, but engine intake pressure drop may cause local temperature drop to zero or below; hence a requirement for engine anti-ice on around 5 degrees C for turbine aircraft. Local heating (e.g. of the outer part of main rotor blades by air friction) may delay ice accretion on some parts of the airframe. Be aware that well below zero c precipitation can remain unfrozen till it hits your aircraft (down to minus 10 rings a bell but I might be wrong - if so someone please correct me.

Total water content: Simple, more water = more ice.

Droplet size: Affects the rate and type of accretion. Small droplets tend to freeze rapidly and form whitish (trapped air), low density, brittle ice. Large, supercooled drops are perhaps most dangerous as they freeze relatively slowly on airframe contact (contain more latent heat) and flow backwards in the airflow. This type of clear ice is "sticky" i.e. adheres more strongly to the surface and it is relatively dense and heavy. Rain ice is an extreme form.

Airspeed: Increasing airspeed cause more rapid droplet contact and increased accretion rate until about 400 kts when surface heating by air friction takes over and reduces it again.

Shape of the affected surface: Droplets have inertia and they cannot change direction as rapidly as the air supporting them. Thinner objects tend to collect more ice. Wider, more rounded ones collect less in the same conditions as the droplets can smoothly follow a gradual path change, although ice may form very rapidly at a stagnation point at the front of an object e.g. on the aircraft nose or ahead of a fairing, depending on design. The windscreen wiper arms are often a good indicator of what might be happening further back on the airframe. Some aircraft have an ice accretion probe (with a thin profile) fitted where the pilot can see it. Flight in icing conditions may then be allowed by the aircraft manufacturer until a certain ice build up occurs.

To my knowledge, the Super Puma is still the only helicopter cleared for unlimited ops in icing conditions. It has electrically heated blades, windscreens, intakes and other surfaces powered by an extra generator, covers over the control rods to main and tail rotors etc etc.

The best advice for helicopters and icing conditions is to vacate the conditions or adopt the "LOALI" principle.

"Land On And Leg It"!

Good explanation Shy. Your -10º analogy is generally correct, but the water has been known to stay in a supercooled state down to -25º.

The problem with icing is that it there we do not have a substantial body of knowledge on the subject. There are so many factors involved in its formation and accumulation, that accurately predicting its effect on a given flight regime is impossible. Something like predicting the weather....we know the general rules, but the complexity of the system defies our ability to accurately and precisely predict it.

As you said, stay out of it. Period.

Shy Torque and CTD,

Good stuff and wise words indeed - stay out of icing conditions!

Just found a UK CAA AIC I had in mind. It is AIC 93/2000 (Pink 8) dated 19 Oct, entitled Frost, Ice & Snow on Aircraft.

This may be of some guidance.

ShyT

Good thread.

CTD, I got your e-mail but I deleted it before I got your address. http://www.pprune.org/ubb/NonCGI/frown.gif Send me another please.

Excellent topic ,learning loads
i did a litle helisking in italy p2 and now i know why they did all that stuff , my italians not that great.
The one thing they used to do if at all posible was to do a really shallow approach and stay on the edge of translational lift , slowly moving foward to the landing site , this gave us a good idea how sticky the snow was , ie if it was going to cause a white out or if it had crusted in the top layer
also gave us an idea how deep the snow was and if the terrain was suitable.
ps , make sure they hold the skis horizontal , they dont mix well with Rotors

Ciao.

:)

A BIG THANK YOU to everyone who has posted ti this thread, I hope others have learned as much as me,and also how little I knew in the first place!

Again thanks to everyone for their time and effort

Regards and safe flying
hoverbover

Bearpaws & snow
 

Hopefully someone may have a solution, but we are often distracted in the snow by calls of "something's fallen off your 'elicopter". Needless to say, it's always a chunk of snow shedding from a bearpaw, after take off. At least, so far it is ;)

Any snow operators (Canadians or Kiwis, I'd guess) have this problem, or even better, a feasible fix? Bearpaws are Dart style thermoplastic jobs, only on the aft end of the skids.

TIA

Having operated for many years in the snow with bear paw equipped aircraft, I'm not sure how to answer. I can't recall having anyone ever call me up on the radio to say they had seen something come off my aircraft just after takeoff.

I'm a little curious, do you get this a lot or just once in a while? Most of the passengers I flew in those years tended to be seasoned helicopter users. I don't know if that made a difference.

Nothing leaps to mind as to a fix for this. I kind of suspect it's just something one has to live with if using bear paws. :)

I used to have calls frequently the first season (5 years ago), but now it's just occasional enough to be a nuisance. Last Monday was the local police out playing on their skidoos, convinced that something important had fallen off!

We're operating from resort to resort, thus sometimes overflying downhill runs or lift lines, so we have a huge number of interested onlookers. 40 flights a day means we're bound to get a call or three, plus patched in to the resort radios means we can't hide :D

John,

haven't had any calls regarding bits falling off, but always see lots of snow coming off in the mirrors and flying along side other helo's.
But have had plently of experience with passengers stomping their feet on the floor trying to remove snow from their shoes, usally just after takeoff - puts the !!!!s up me everytime!!.

Any experince along these lines??


BigJim :eek: :eek:

Talking ballast/pax shouldn't be allowed ;) After the first season of shifting skiers, we had to insert sheets of heavy gauge alloy on the floor, to protect the (crushed) honeycomb where ski boots had done their thing. That was through a thick rubber floor covering! Sheets of stainless steel around the door pillars & cabin sides for more protection, and a vigilant ground crew to 'discourage' knocking snow off against the door sill as they get in.

The rubber floor mat stops any noise from boots being knocked on the floor, but they certainly enjoy the ride, and a good heater soon warms things up once we're airborne.

Only a couple of weeks left to the end of our ski season, and NSW has had about 5 bushfires already, so no doubt we'll swing into that fairly soon.

Look out for a super large flag tow over the VFL Grand Final in two weeks, >40,000 sq ft :eek:

John,

limit your pax to snowboarders only with soft boots!! (and make sure the good looking ones are always in the front), sure to solve nasty plastic boot marks :). We use plywood floor liners which are good, but I'm sure a moulded polythene liner made by Tufdeck would look much nicer :D

BigJim

[ 13 September 2001: Message edited by: BigJim ]

US NTSB urges Helicopter IF ratings for pilots in Snowy Climes
 

I saw this press release in a trade paper....

PRESS RELEASE

Date 08 October 2002

NTSB urges FAA to require helicopter Instrument Rating in snowy climes

The U.S. National Transportation Safety Board (NTSB) today urged the Federal Aviation Administration (FAA) to require “all helicopter pilots who conduct commercial, passenger-carrying flights in areas where flat light or whiteout conditions routinely occur to possess a helicopter-specific instrument rating and to demonstrate their instrument competency during initial and recurrent . . . check flights.” NTSB Recommendation A-02-33. In addition, NTSB wants FAA to require operators in these areas “to include safe practices for operating in flat light or whiteout conditions in their approved training programs,” and mandate “installation of radar altimeters in all helicopters conducting commercial, passenger-carrying operations in areas where flat light or whiteout conditions routinely occur.” NTSB Recommendations A-02-34 and A-02-35. The full text of these NTSB recommendations is available via Internet at http://www.ntsb.gov/recs/letters/2002/A02_33_35.pdf.


How many commerical operators will actively support these reccomendations and promptly equip the aircraft with the instruments and train and test their pilots to this standard? Care to hazard a guess......mine is "Zero...zip...nada....nil...."



:rolleyes:

SASless,
I guess you're right. For commercial operators the only 3 things which matter, in order of priority are, profit, profit, profit. Which is rather sad as I seem to remember from some previous posts of yours that you once worked in Nigeria for a large operator of whom you seemed to be rather fond;) I seem to remember that one of their pilots from there went to fly a Bell 206 for the British Antarctic Survey and crashed in the snow. Of course that was said to have been due to a faulty heater causing carbon monoxide poisoning, but.....
:confused:

Looking at the past history of the FAA in responding to NTSB recommendations, I believe the chances of the FAA accepting these is very close to zero. As regards the motives of operators, I think you're a little broad there, MamboBaas. The motive is not just profit, but short-range profit. Few look at next year, much less next quarter. They take the money & run now, & next year will take care of itself, if they're still in business. :(

Low Vis Training
 

I believe that in Canada low vis ops are a required part of recurrent training. Admittedly, it's only a few questions on a written test, usually administered in the spring. Maybe an IFR requirement wouldn't be a bad thing...

In Helicopters Mag issue #2/2001 (Canadian publication: www.helicoptersmagazine.com) there's an excellent article on low vis training. It's a good read for this (or any) time of year.

Can we be trusted to know and respect legal vis limits, or do we need to have more legislation? Since the CPL is already a legal, skills-and-knowledge certification, adding IFR for snowy conditions isn't a conceptual quantum leap. But it still wouldn't mitigate the issue of customer pressure to complete the mission. None of my LZs have an instrument approach, so an IFR rating and radar alt would help me avoid CFIT, but won't help me reach my destination.

The real point of such legislation must be to ensure that we can turn around after inadvertent flight into IMC. Fair enough. Keeping the skills sharp during a season of (primarily) VMC is another question. As is getting every friggin helicopter in Canada outfitted with a radar alt! Bet there'll be some operator resistance the that one!!

Yawn!
 

The problem still remains that very few pilots know what whiteout is. No it is not as everyone suspects flight in falling or blowing snow. For those who have never experienced it imagine flying along in the dark and flying into an unlit object that you obviously couldn't see. The same can happen in whiteout - it is so white or bright that your eye cannot differentiate. The worst situation is a flat overcast making flat light conditions.

All the instruments in the world will not help and are not a solution - a DC 10 in Antarctica proved this once. In flight visibility was in excess of 150 miles. White cloud base, white snow, white mountain no shadows - whoop whoop WTF...........

The problem will remain that unless you are aware of the phenomena you will not recognise it - simple.

You would have to ask why no less than 3 AS350's ended up lying on their sides in one day in Alaska - all from the same company. Instruments and instrument ratings is far from the answer.

Bicker.....Hi Ya, Buddy! I suppose that was the way Ops wanted them parked. Famous quote I heard up there was " I don't give a damn what the weather is....tell the SOB to get that aircraft to Fairbanks or he can find another job!" ......and the fourteen year veteran Alaska pilot did just that....told them to stuff their job up their bunghole and got another job the same day. If you are referring to the "large" company with the 121 fixed wing side... they had the highest accident rate in Alaska (helicopter side) for several years running. You are talking about the same company that also did the same thing with two 212's or a 212 and 412 just outside Deadhorse/Pruhoe Bay one year too? Red/Black/White machines.

John Bicker wasn't referring to Era, he was talking about Temsco. September 10, 1999 was a day Temsco would rather forget.

One of their Astars with six people aboard crashed in low-viz/flat light conditions up on a glacier in Alaska. A search was initiated and subsequently another Astar with two persons aboard crashed. A third Astar found them, picked them up and continued to search for the first downed Astar, but alas, even it crashed! All were relatively gentle crashes that tore the ships up but didn't hurt anyone very seriously (with the exception of one person on the original ship).

The Base Manager was out searching in a fourth Astar. One can only imagine his anxiety upon hearing that a total of three of his ships were down (with one hapless crew being involved in two accidents in the same day!).

It is noted that only one of the three pilots had an Instrument Rating. The NTSB must be using this as a "cookie-cutter" cause, but their reasoning is specious because none of the three pilots reported any problems controlling their respective aircraft prior to smooshing into the snow. They all hit fairly level and under control, hence the "C" in CFIT. We can therefore conclude that the Instrument Rating by itself would not have prevented any of these accidents.

But a radar altimeter might have! The pilots reported that they thought they were higher than they actually were (kind of a "duh!" eh?). Had the information from a RadAlt been available, they might have known otherwise.

Having an Instrument Rating does you absolutely no good if:
1) you don't know where you are relative to higher terrain; and
2) you have no way of knowing how high you are with respect to the terrain immediately under you.

Rad Alt s all round
 

.... economics dictate:

Rad Alts are worth it - save you a fortune when you need them!

Guess it was Temsco. Was there in July of '99 with a Cayman Islands registered MD 600 - don't ask!

Was intrigued by the FAR's or recommendations, that your survival equipment should include a mosquito/bug hat and at least a shotgun.

Figured out after flying around for a bit that the gun was there so that if you crashed you could shoot yourself before a bear ate you.

Beautiful place and would definitely return!

Rad alt didn't help that DC-10 in Antarctica. Nor will it help if you are flying towards steeply rising terrain. It would also help if you are actually watching it too. How safe would you feel riding shotgun while some guy flies at 200'agl while he watches the rad alt in poor viz ?? I think I would be asking him to please turn around !! Besides, didn't one of you say that one of the pilots already had an instrument rating ?? Did him a lot of good. ;)

Dick our company ops-spec requires training once per year on low-viz ops. But it doesn't take long to do a couple of 360's in the a/c at 200' agl (or whatever height you feel comfortable at). Generally speaking when doing VFR recurrent training, we almost always have a little time to do company minimum airspeed, low-level flying. We pick a day with some wind, and in between autos, t/r failures, we go and do a couple of 360's at low level in the infield of the airfield. You have to do an hour's training anyways. Besides it's fun, and gets us ready for orbitting fires ad nauseum. :D

Cheers

Randy....would not practicing 180's be more beneficial.....really....doing a 360 to get out of trouble seems .....well....kind of ethnic somehow!

Plus.....I would like to know just how many hundreds if not thousands of hours I have at 200 feet in bad vis.....heck...I would like to know how many hours I have at 50 feet in bad vis......tree tops give a great altitude reference from below....and amazingly enough....most tree trunks point up....there by giving one an attitude reference. In our cowboy days it was not unheard of to ask the cabin attendent to slide the cabin door back and look down to warn us of the sea.

Don't get confused here. The trap in the DC10 and I think the Alaskan incidents was "sector whiteout". In the DC10 incident the flight visibility was in excess of 150 miles. The FMS was programmed so that they were'nt where they thought they were which is really incidental. The whole crew thought they were in the clear and could see the coastline and several other features clearly. They were well below the cloudbase. The white cloudbase, white mountain covered in white snow was undetectable to the capabilities of the human eye. During all the investigations the same course was flown in a US military 212 from Mc Murdo about a year (I think) later to the day. The same conditions existed and said mountain was not visible. The conditions of sector whiteout are never apparent and you have no reason to even think about using instruments unless you know the symptoms that cause it. The conditions were VMC and the aircraft were not in any sort of precipitation.

Unless you have experienced it yourself it is difficult to appreciate or describe to someone else how deceptive it is.

To fully understand the NTSB recommendations, it might be worth reading the relevant accident reports.

Temsco #1

Temsco #2

Temsco #3

Coastal

Temsco committed to the NTSB that they would;
When you are carrying paying tourists in new aircraft the cost of a rad-alt is peanuts to the cost of the entire aircraft (especially if you install a $5,000 stereo system :eek: ).

Any other costs incurred in operating safely will be peanuts in relation to your insurance premium after a disaster of this nature.

Whether it becomes mandated will be interesting to see, and quite how you define "snowy-climes" might also pose a challenge, as seasonally that covers a lot of territory!

A couple of other lessons from this might include notifying the appropriate authorities that you have a (number of) machine(s) missing, rather than have the local media calling the FAA for information about 3 A-stars crashing on the glacier (say, what):eek:!!!!!

Some time later, a TV crew appeared to film a show about this incident. In the segment however, only two helicopters crashed on the ice because they did not think the TV viewing public would believe that 3 could crash successively!:rolleyes:

As regards flat-light conditions, anyone who has been ski-ing has probably run into this exact condition - totally featureless terrain and the inability to determine any physical definition. CFIT in these conditions is not limited to helicopters and mountains, but also fixed wing aircraft in relatively good visibility and flat ground but a featureless landscape, sky and horizon.

Intentional IFR flight in the area these accidents occurred in would be guarantee the demise of anyone unfortunate enough to try it. I've met a couple of fixed-wing guys who inadvertently tried it (exhibiting severe shock) and also pulled quite a few wrecks out where they weren't so lucky!

John, you will be pleased to hear that Alaska has removed the requirement to carry a gun at all times in the State, as it is impossible to take it through Canada! It is however a pretty good idea if you are going to do much travelling to buy one there - if you ever faced up to a bear in the woods, you would wish you had it. As regards mosquito nets and bug-dope - never, ever, consider going anywhere in the North without them in your survival gear, as they WILL kill you! ;)

Flying in snow
 

While its not exactly the time of year for it I was just curious for input from some of the seasoned snow flyers about the profiles they use when operating in snow.
1. Runway takeoff... I would assume pulling in all the power from flat pitch and transitioning away as quickly as possible avoiding the hover.
2. Landing.... A shallow approach with touchdown, again avoiding the hover... what about on un prepared LZ s for example in the mountains...?

Any input would greatly appreciated especially from those who have flown in the snow on wheels.
Thanks ...Decks

The guys who have seemed to do well in training in these conditions are Canadian Helicopters. www.canadianhelicopters.com
Other than comments here, you may want to get an email through and see if one of their instructors can give you some tips.
As for me I uses my snow card. Its blue and I hold it up to the sky. If the colors don't match, its time for coffee.

Snow Glorious Snow
 

Hey guys,

Whats the deal with the snow drama in the U.K?

MAN has had disruptions, LGW was like an ants nest gone wrong?

Is it right and proper that a country that has snow EVERY year has major disruptions due to ignorance??

I know that most line pilots in the UK have no experience in flying in snow and shiiiiit.'.............( I am waiting for the come back)

Only look at what the Canadiens and the Norwegians put in, and they manage ok, cos they know it's coming.

Are the UK Aviation and Road people ###ing stupid. Or are resources stretched past their limit due to ignorance.??

MD :mad: :mad:

Planks have a whole sort of de icing procedure going on, i would like to hear about the varoius experiences of de-icing in pprune. Rotors going or not?)

The hanger is the best solution for deicing. That and staying out of the fluffy stuff. :hmm:

Don't worry mate: the drivers in canada are just as bad. Which is strange because they grew up with it.