Flying in snow
Guest
Posts: n/a
Flying in snow
Dear All
What experiences does anyone have flying in snow/freezing conditions?
What I really would like to know are the DO's and DONTs obviously things like visibility,recirculation white out in the hover are some problems which can be expanded on but my main concern is are there temperatures and snow types you avoid flying in.
I have done some flying in snow but would appreciate anyones experiences (good and bad)so that hopefully I can learn some more.
Obviously flight into known icing is a definite no go.
I hope someone can enlighten me !!!!!
Regards
hoverbover
PS
Most of my flying is in the UK.
What experiences does anyone have flying in snow/freezing conditions?
What I really would like to know are the DO's and DONTs obviously things like visibility,recirculation white out in the hover are some problems which can be expanded on but my main concern is are there temperatures and snow types you avoid flying in.
I have done some flying in snow but would appreciate anyones experiences (good and bad)so that hopefully I can learn some more.
Obviously flight into known icing is a definite no go.
I hope someone can enlighten me !!!!!
Regards
hoverbover
PS
Most of my flying is in the UK.
Guest
Posts: n/a
Surely your flight manual will tell you the limits?
If you aren't famil with those, try these:
Do not fly in visible moisture below 0 degrees, is good karma for MOST civvy pilots. Due to the venturi effect at the engine intakes (Po) this drops further causing freezing and the engines could cut out!
The same for snow. Don't fly in snow below 0 degrees due to icing. Down to this is ok provided you MONITOR the "stickability"...i.e. if it is building fast and obscuring your view or building too much near the intake(s) then vacate the area. NORMALLY this only becomes a problem when the viz drops to <500m.
White out can wipe you out within seconds. IF you have to land in fresh snow, then adopt a zero / zero technique landing. This keeps you inside the snow vortices for the min amount of time. Don't practice Z/Z's for the first time in snow!!!!
Same goes for the takeoff.
Happy Christmas..
Edited due to some absolute b****cks I printed earlier!
------------------
Thermal runaway.
[This message has been edited by Thomas coupling (edited 06 March 2001).]
If you aren't famil with those, try these:
Do not fly in visible moisture below 0 degrees, is good karma for MOST civvy pilots. Due to the venturi effect at the engine intakes (Po) this drops further causing freezing and the engines could cut out!
The same for snow. Don't fly in snow below 0 degrees due to icing. Down to this is ok provided you MONITOR the "stickability"...i.e. if it is building fast and obscuring your view or building too much near the intake(s) then vacate the area. NORMALLY this only becomes a problem when the viz drops to <500m.
White out can wipe you out within seconds. IF you have to land in fresh snow, then adopt a zero / zero technique landing. This keeps you inside the snow vortices for the min amount of time. Don't practice Z/Z's for the first time in snow!!!!
Same goes for the takeoff.
Happy Christmas..
Edited due to some absolute b****cks I printed earlier!
------------------
Thermal runaway.
[This message has been edited by Thomas coupling (edited 06 March 2001).]
Guest
Posts: n/a
Zero airspeed / zero rate of descent...all coming together at the same time and place! It tends to be 'positive arrival' compared to pussy footing about in the hover prior to touchdown. Take off: pull take off pwr and rotate immediately...in that order!!
Problems: If you don't know what the surface is like (depth etc) then because of the positive landing, there is a risk you may sink thru the light surface and damage the undercarriage. If you try and lighten the touchdown by pulling some power...you'll white out!
Take off: If you've been on the frozen deck for too long, you may stick to it sufficiently to overtemp an engine trying to break free!!
Fun and games....
------------------
Thermal runaway.
Problems: If you don't know what the surface is like (depth etc) then because of the positive landing, there is a risk you may sink thru the light surface and damage the undercarriage. If you try and lighten the touchdown by pulling some power...you'll white out!
Take off: If you've been on the frozen deck for too long, you may stick to it sufficiently to overtemp an engine trying to break free!!
Fun and games....
------------------
Thermal runaway.
Guest
Posts: n/a
Hoverbover,
I had a recent experience in snow / icing conditions last weekend which nearly cost me an R22.
Following a training flight with a student i departed the airfield to return home. Due to poor visabilty (1km) / snow showers i decided to land the aircraft in a field and wait for the snow showers to clear.
The snow did not clear and i abandoned the helicopter. The ground was very soft and boggy.
I returned to the helicopter the following morning with a student, the conditions clear blue sky minus 5 degrees prefect flying conditions. Whilst walking to the aircraft i was explaining the dangers of dymanic rollover.
We arrived at the aircraft and as i suspected the aircraft skids were frozen to the ground. We stamped the ground down both sides of the skids to free the aircraft from the ground. We preceeded with the normal preflight check / start up. We are now at full power and ready to lift, the aircraft became light on its skids and i inputed left and right yaw pedals to slide the aircraft from side to side to free the landing gear from the ground. I made a special point of yawing the aircraft to free it from the ground having flown serveral weeks in the Swiss / French Alps and experinced this several times previously. We are now light on the skids and looking outside the student at the controls whist i followed through he continued raising the lever within a split second the aircraft lifted on the passenger side and possibly the front part of the landing gear to the pilots side. The aircraft almost went over i dumped the lever and shut down the aircraft. After exiting the aircraft it became apparent that whilst shuffling on the ground i had in fact shuffled the rear spade part of the landing gear under the very soft suface (Crisp and hard on the surface very soft below)preventing the aircraft from lifting.
Very close call. I will be extremely cautious in future
Any simular occurences?
I had a recent experience in snow / icing conditions last weekend which nearly cost me an R22.
Following a training flight with a student i departed the airfield to return home. Due to poor visabilty (1km) / snow showers i decided to land the aircraft in a field and wait for the snow showers to clear.
The snow did not clear and i abandoned the helicopter. The ground was very soft and boggy.
I returned to the helicopter the following morning with a student, the conditions clear blue sky minus 5 degrees prefect flying conditions. Whilst walking to the aircraft i was explaining the dangers of dymanic rollover.
We arrived at the aircraft and as i suspected the aircraft skids were frozen to the ground. We stamped the ground down both sides of the skids to free the aircraft from the ground. We preceeded with the normal preflight check / start up. We are now at full power and ready to lift, the aircraft became light on its skids and i inputed left and right yaw pedals to slide the aircraft from side to side to free the landing gear from the ground. I made a special point of yawing the aircraft to free it from the ground having flown serveral weeks in the Swiss / French Alps and experinced this several times previously. We are now light on the skids and looking outside the student at the controls whist i followed through he continued raising the lever within a split second the aircraft lifted on the passenger side and possibly the front part of the landing gear to the pilots side. The aircraft almost went over i dumped the lever and shut down the aircraft. After exiting the aircraft it became apparent that whilst shuffling on the ground i had in fact shuffled the rear spade part of the landing gear under the very soft suface (Crisp and hard on the surface very soft below)preventing the aircraft from lifting.
Very close call. I will be extremely cautious in future
Any simular occurences?
Guest
Posts: n/a
You will find in the 520 manual ( plus other 500 variants ) you may fly in falling snow providing you have the following. No centre seat pax ( never been able to work this out or find anyone who knows - anyone enlighten me ? ); autorelight on and armed, I would suggest that anti ice is on as the temp will be below 5 degrees and you certainly have visible moisture.
Other points, as you will have cabin heat and anti ice on watch your TOT espically if you are heavy. TOT starts to rise the inlet may becoming blocked - unlikely but possible.
Heed everyone else's advice get someone to show you
What Notar do you fly in UK, presumably a 600 as there are no 520 in UK I think ???
Other points, as you will have cabin heat and anti ice on watch your TOT espically if you are heavy. TOT starts to rise the inlet may becoming blocked - unlikely but possible.
Heed everyone else's advice get someone to show you
What Notar do you fly in UK, presumably a 600 as there are no 520 in UK I think ???
Guest
Posts: n/a
I think no centre seat front passenger might be to keep C of G more rearward.500 has a problem in snow[especially wet snow] that it can build up on the top of the perspex then break off going through the compressor in a big chunk. A lot of weight in front would givea more nose down attitude.I personally have had this happen and on one occasion over a large densely wooded area had 3 flameouts in ten minutes,relit each time by the auto relight.Problem exacerbated by the fact that in these conditions of heavy wet snow speed is back around 60 knots because of the vis and also you will be at a low altitude for the same reason.
I would guess that the no centre seat pax rule is an attempt by the manufacturer to address this problem.Its a while since I flew a 500 and I don't recall any similar restriction was in the 500D manual, but the problem was well known to those of us flying it in winter. I'm only guessing the reason its there for a 520.
I would guess that the no centre seat pax rule is an attempt by the manufacturer to address this problem.Its a while since I flew a 500 and I don't recall any similar restriction was in the 500D manual, but the problem was well known to those of us flying it in winter. I'm only guessing the reason its there for a 520.
Guest
Posts: n/a
With a passenger in the centre seat, you may not be able to reach and open the auxiliary air inlet, should the particle sep become blocked with ice/snow. I don't believe it has anything to do with CofG. I've had it flame-out & relight while in straight and level while slinging. The a/c was no more nosedown than in normal flight.
If you do want to fly in falling snow, get ahold of a proper snow deflector. That way there's no flameout problems.
Make absolute sure that your skids are clear, and free from the ground before you start up. With an R22 take hold of the T/R gearbox, and pull down. It should go down with reasonable ease. Our engineer said that the force needed to lift the skids will not harm the tailboom or it's attachment. The same goes for the 500 series. Pull down on the tail, until both skids squat, then lift it back up.
If you don't have experience in snow that is deeper than ankle deep, I recommend you get instruction (try a holiday to Canada, or Switzerland where they get snow)!!! It is very easy to put the a/c into dynamic rollover if you aren't very careful. If you've shut down, get out and remove the snow from around the skids, to check to make sure the skids are clear. It's best if you can give yourself something to use as a reference. A stake, or clearing a spot right down to the ground. Be easy on the controls, and once clear of the surface, get out of the snowball quickly.
There is a good saying that may help. "If in doubt, don't".
If you do want to fly in falling snow, get ahold of a proper snow deflector. That way there's no flameout problems.
Make absolute sure that your skids are clear, and free from the ground before you start up. With an R22 take hold of the T/R gearbox, and pull down. It should go down with reasonable ease. Our engineer said that the force needed to lift the skids will not harm the tailboom or it's attachment. The same goes for the 500 series. Pull down on the tail, until both skids squat, then lift it back up.
If you don't have experience in snow that is deeper than ankle deep, I recommend you get instruction (try a holiday to Canada, or Switzerland where they get snow)!!! It is very easy to put the a/c into dynamic rollover if you aren't very careful. If you've shut down, get out and remove the snow from around the skids, to check to make sure the skids are clear. It's best if you can give yourself something to use as a reference. A stake, or clearing a spot right down to the ground. Be easy on the controls, and once clear of the surface, get out of the snowball quickly.
There is a good saying that may help. "If in doubt, don't".
Guest
Posts: n/a
knhxyy
There was a thread on skids frozen back in December, it might be worth a read.
In brief though, lower tail (as above) or even use a pole as a lever under the skids, anything to ensure that the skids are not stuck before a start.
Also beware that latent heat from the skids may melt ice/snow on landing, only to refreeze in minutes. Never trust that ice or snow even if you have landed for two minutes
and not shut down....
There was a thread on skids frozen back in December, it might be worth a read.
In brief though, lower tail (as above) or even use a pole as a lever under the skids, anything to ensure that the skids are not stuck before a start.
Also beware that latent heat from the skids may melt ice/snow on landing, only to refreeze in minutes. Never trust that ice or snow even if you have landed for two minutes
and not shut down....
Guest
Posts: n/a
To all
Many thanks for the info, keep it coming, all the warnings are taken on board.And hopefully others will learn as much as possible, like me.
To TC
As you say the RFM allows flight in snow but their are no limits on temperatures etc.(except for the operation of the anti ice below +5 c with visible moisture, personnaly any time the temp is lower than +5 c I use the anti ice anyway visible moisture or not)
Many thanks for your sound advice, You learn something every day (I had always guessed that 0to+3 C would be the worse conditions for snow accreation and it would get less sticky the colder it got under 0C.)
To Hughes500
Thanks for the info, on the subject of aircraft could be !!!!!! But there is a 520 Notar in the UK (on the N reg at the moment)
and all advice is gratefully received
Thanks to EVERYONE and keep the info coming, and please don't worry I have no desire to fly in snow without the proper training(anybody got any ideas on who/where)but would like to be prepared.
Regards
hoverbover
Many thanks for the info, keep it coming, all the warnings are taken on board.And hopefully others will learn as much as possible, like me.
To TC
As you say the RFM allows flight in snow but their are no limits on temperatures etc.(except for the operation of the anti ice below +5 c with visible moisture, personnaly any time the temp is lower than +5 c I use the anti ice anyway visible moisture or not)
Many thanks for your sound advice, You learn something every day (I had always guessed that 0to+3 C would be the worse conditions for snow accreation and it would get less sticky the colder it got under 0C.)
To Hughes500
Thanks for the info, on the subject of aircraft could be !!!!!! But there is a 520 Notar in the UK (on the N reg at the moment)
and all advice is gratefully received
Thanks to EVERYONE and keep the info coming, and please don't worry I have no desire to fly in snow without the proper training(anybody got any ideas on who/where)but would like to be prepared.
Regards
hoverbover
Guest
Posts: n/a
Randy G, can't be anything to do with filter by pass its located by your right ear on HS,C and D models not sure on Notars. I like the C of G idea though or perhaps is there a danger of centre seat pax knocking off autorelight with a foot. The switch on all machines is about 2" off the floor ???
Nice topic this one espically as I had 2" of snow at the weekend on Dartmoor - ha ha I hear you say.
Cheers
------------------
Nice topic this one espically as I had 2" of snow at the weekend on Dartmoor - ha ha I hear you say.
Cheers
------------------
Guest
Posts: n/a
Randy G has a point. When it happened to me the day I had multiple failures,I was only doing about 60 knots [vis about half a mile]so there wouldn't have been a big nose down attitude.That day was probably an ideal combination of temperature, moisture etc to get that heavy wet and sticky snow.We had resisted snow deflectors up until then as the TOT increase from them restricted our ability to move drills at the altitudes required. Used them after that if it even looked like snow.
My point was more that Flight Manuals these days are written by lawyers and they come up with all kinds of protective measures when a known weakness exists.When I can't think of an obvious reason for something that's what my suspicious mind concludes.
My point was more that Flight Manuals these days are written by lawyers and they come up with all kinds of protective measures when a known weakness exists.When I can't think of an obvious reason for something that's what my suspicious mind concludes.
Guest
Posts: n/a
This was lifted from the FAA preliminary accident data report.
1996 BELL 406 HELICOPTER DROPPED OFF SKIERS, RETURNING TO
REPOSITION, SET HELICOPTER DOWN, SNOW CAVED, HELICOPTER ROLLED,
TAILBOOM OFF, ROTOR BLADE DAMAGED, JACKSON, WY
------------------
The Cat
1996 BELL 406 HELICOPTER DROPPED OFF SKIERS, RETURNING TO
REPOSITION, SET HELICOPTER DOWN, SNOW CAVED, HELICOPTER ROLLED,
TAILBOOM OFF, ROTOR BLADE DAMAGED, JACKSON, WY
------------------
The Cat
Guest
Posts: n/a
The no centre seat occupant restriction in falling snow on the Hughes 500 is because the original engine relight switch box was located lower on the console, and was difficult to reach with the centre seat occupied. All of our 500's (I'm talking in the 80's) had the relight moved to the upper right of the panel, and the centre seat restriction was lifted. It has nothing to do with C of G or the Filter Bypass door.
It is difficult to nail down blanket rules for flight in snow, as each helicopter and situation are unique. Not sure I can go along with the 'zero/zero' technique. This may work for very light snow conditions at airports but is not appropriate for use in heavier snow or unprepared sites, and can lead to more trouble than its worth.
One method commonly used for take-off in snow is to start to apply a little power until the snow begins to fly, retaining reference with the ground. Continue to apply power without going airborne until the snow has diminished to the point where a good reference is available. Lift the aircraft into a low hover, keeping your reference visual, then climb to a high hover and depart over the snowball. The main thing is to keep some reference available at all times.
For landing, plan your approach to a spot with some form of reference available. This can be the side of a building, a small tree, a fuel drum, etc. Bring the aircraft into a high hover, while maintaining reference with your spot, and allowing the downwash to clear the snow. Slowly lower the aircraft to the landing site as the clearing snow permits visual contact to be maintained.
Thomas Coupling...I have to take exception with several of your points. You say "Do not fly in visible moisture below +5 degrees, is good karma for MOST civvy helos. Due to the venturi effect at the engine intakes (Po) this drops to just above freezing and the engines could cut out!" This is absolute rubbish.
You also say "This time don't fly in snow below 0 degrees due to icing." Again, rubbish.
And...."If you've been on the frozen deck for too long, you may stick to it sufficiently to overtemp an engine trying to break free!!" Over temp in winter? What exactly do you fly?
Flight in snow, when properly equipped is as safe as flight in rain. There are places in the world after all where flight in heavy snow conditions are a daily occurance, and operations are conducted in a safe and efficient manner. Mr Coupling...If you don't know what you're talking about, please don't impart your dangerous level of inexperience on others.
[This message has been edited by Tiercel (edited 06 March 2001).]
It is difficult to nail down blanket rules for flight in snow, as each helicopter and situation are unique. Not sure I can go along with the 'zero/zero' technique. This may work for very light snow conditions at airports but is not appropriate for use in heavier snow or unprepared sites, and can lead to more trouble than its worth.
One method commonly used for take-off in snow is to start to apply a little power until the snow begins to fly, retaining reference with the ground. Continue to apply power without going airborne until the snow has diminished to the point where a good reference is available. Lift the aircraft into a low hover, keeping your reference visual, then climb to a high hover and depart over the snowball. The main thing is to keep some reference available at all times.
For landing, plan your approach to a spot with some form of reference available. This can be the side of a building, a small tree, a fuel drum, etc. Bring the aircraft into a high hover, while maintaining reference with your spot, and allowing the downwash to clear the snow. Slowly lower the aircraft to the landing site as the clearing snow permits visual contact to be maintained.
Thomas Coupling...I have to take exception with several of your points. You say "Do not fly in visible moisture below +5 degrees, is good karma for MOST civvy helos. Due to the venturi effect at the engine intakes (Po) this drops to just above freezing and the engines could cut out!" This is absolute rubbish.
You also say "This time don't fly in snow below 0 degrees due to icing." Again, rubbish.
And...."If you've been on the frozen deck for too long, you may stick to it sufficiently to overtemp an engine trying to break free!!" Over temp in winter? What exactly do you fly?
Flight in snow, when properly equipped is as safe as flight in rain. There are places in the world after all where flight in heavy snow conditions are a daily occurance, and operations are conducted in a safe and efficient manner. Mr Coupling...If you don't know what you're talking about, please don't impart your dangerous level of inexperience on others.
[This message has been edited by Tiercel (edited 06 March 2001).]
Guest
Posts: n/a
And of course in winter weather: DON't place your tongue on any part of the cold frozen heli, it might stick to it, and you will look silly. 
(Well ... I had to add somethin ...)
------------------
Marc
[This message has been edited by RW-1 (edited 06 March 2001).]
(Well ... I had to add somethin ...)
------------------
Marc
[This message has been edited by RW-1 (edited 06 March 2001).]
Guest
Posts: n/a
To Tiercel
All great advice, what about in flight conditions to avoid like certain temperatures etc.(i know its an open ended queston but any advice is greatly appreciated)
To Hughes500
Must have been pretty at the weekend, wasn't too far away myself but it was dark.
Again I hope others are learning as much from this thread as me,
Regards
hoverbover
All great advice, what about in flight conditions to avoid like certain temperatures etc.(i know its an open ended queston but any advice is greatly appreciated)
To Hughes500
Must have been pretty at the weekend, wasn't too far away myself but it was dark.
Again I hope others are learning as much from this thread as me,
Regards
hoverbover