Landing In Deep Snow?

[mountainflier]

Hey there everyone...

 

My curiousity has gotten hold of me...

 

I have seen a bunch of pictures (posted on our site) of Astars, R44's, etc that were landed in semi-deep to deep snow. Obviously, the weight of the helo is not supported by the skids in this case. Since I have yet to experience this type of landing, what precautions or checklist do you perform to make sure that you don't bend any belly antennae, etc (or worse - settle down into a snow covered rock?).

 

Thanks!

[T-rex]

Beware of the "Snowball Effect" They can bite hard! Anticipate one everytime and prepare for it! A good reference point is the key, ensure maybe OGE hover for the first times of the season, this allows those extra safety measures.

Watch and feel for hard or crusty snow, ensure you do a slow seating check!!!

 

If you can detect informalities in the snow surface, that may indicate that an object may be under neath, your only cure is slow and easy.

 

If you land on a snow covered ridge, ensure you stay back from the overhang, an easy way to write off a machine by static rollover.

 

Try not to land in cutblocks unless the snow is deep, those stumps can do your belly in!

 

The aircraft in deep snow will likely rest on its belly parts among others, like I said, slow! In an Astar ensure your swing isn't pinned agianst your fuel drain, cause you may get a real neat surprise on the fuel gauge an hour or two later, most companies disconnect the fuel drain on the 350 series.

 

When lifting off, slow and easy, eyes out front, NOT in your mirror, thus maybe catching a rollover possiblity with your skids or bearpaws catching the snow crust.

 

You should ask your CP for a winter initation ride, This will be your best information you can get...hands on!

 

I am sure the guy and gals on here will fill your head with alot other great ideas that I missed.

 

I can't over stress that you should do a quick ride with your CP or another experienced company pilot!

[Guest sharky]

A good question, at the right time of year!

 

Having a reference is paramount if you're landing in an open area (a stump, a tree, etc). With snow all around you, and white dust blowing everywhere, you may not be able to detect your height, or unwanted movement of the helicopter. This is when machines get rolled over.

 

The Aviation Safety Vortex of 1/03 suggests having a reference within the rotor disk. This works great because you can still see it regardless of how much snow is blowing around.

 

Upon touchdown, apply forward cyclic as you seat the machine in with collective. This will force the front of the landing gear in deeper than the rear, keeping the tail rotor high and clear. Be sure to remind your pax of safe directions to approach and leave the aircraft as the blade tips will be much closer to the ground in front of the aircraft in this situation.

 

Here's the Aviation Safety Vortex 1/03, for a refresher

 

Snow Landing and Take-off Techniques

Throughout the course of winter operations, helicopters face a significant hazard associated with takeoffs, landings and hovering when the ground is covered with fresh or light snow. The rotor down wash can produce a flurry of re-circulating snow, reducing local visibility and causing whiteout conditions. There seems to be limited reference material available on the subject, but the following techniques are used by the industry as standard practice.

 

The towering takeoff

When conducting takeoffs in conditions conducive to re-circulating snow, apply enough power to get the snow blowing while keeping enough weight on the aircraft to prevent it from moving. Leave the power on as long as necessary to get good visual references. This could take up to a minute to accomplish.

 

Once good references are established, use a towering take-off technique (altitude over airspeed) to stay out of the re-circulating snow during the remainder of the departure procedure.

 

If the aircraft is equipped with a wheeled undercarriage and a runway is available, a rolling takeoff could be another option.

 

The rolling takeoff

Prior to starting the take-off roll, apply power to blow the runway clear in the vicinity of the aircraft — this will give you some reference for the start of the take-off roll. When ready for takeoff, apply enough power to get the aircraft accelerating ahead of the re-circulating snow. When ahead of the snow, lift the aircraft into the air, accelerate to the aircraft’s normal climb speed and follow the normal climb profile.

 

Use this technique when the snow cover is light (less than approximately 5 cm), and the snow is relatively dry. Deep or heavy snow could impose excessive load on the landing gear.

 

Landing: high-hover technique

Before using this technique, ensure that the aircraft is at a weight that will allow hover out of ground effect performance. If the aircraft is flying in clear air prior to the approach, activate the aircraft’s anti-ice systems (if equipped) prior to entering the re-circulating snow.

 

Plan your approach to arrive in a high hover above the landing site. This hover could be several rotor diameters above ground depending on snow conditions, aircraft weight, rotor diameter, and aircraft type.

 

When in a high hover, the re-circulating snow will form beneath the helicopter, obscuring the landing site. This re-circulating snow will also rise; be sure to stay above the rising snow and wait until solid references appear beneath the aircraft. This could take up to a minute. These references are directly under the aircraft and within the diameter of the rotor disc. Once solid references have been obtained, a slow vertical descent to a touchdown is all that is required.

 

Landing: no-hover technique

This technique is generally used when aircraft do not have hover out of ground effect performance. The idea is to fly the approach fast enough to keep ahead of the re-circulating snow and complete a no-hover landing before the re-circulating snow engulfs the aircraft, causing local white out conditions.

 

Some of the negative aspects of this technique:

 

Requires excellent timing — usually only one chance at getting it right.

May not be able to get a detailed look at the touchdown area prior to landing.

Not recommended for use at night helipads because of the reduced visual references required for judging the landing flare.

The run-on landing

A run-on landing could be another option, if your aircraft is equipped with a wheeled undercarriage and you are landing on a runway.

 

The technique is to fly the approach fast enough to keep well ahead of the re-circulating snow. On touch down, the aircraft has to have enough forward speed to stay ahead of the re-circulating snow and allow the collective to be fully lowered (lowering the collective reduces the re-circulating snow). Bring the aircraft to a full stop and taxi with caution.

 

Use this technique when the snow cover is light (less than approximately 5 cm), and the snow is relatively dry. Deep or heavy snow could impose excessive load on the landing gear.

Safety first

Landings and takeoffs in re-circulating snow require skill, training, and adherence to the following safety points:

 

Be certain you have sufficient power available to permit the manoeuvre.

To prevent dynamic rollover, ensure that the skids or wheels are not frozen to the ground prior to lift off.

Observe the flight manual and company operations manual limitations. In the transport category, the height-velocity diagram is a limitation and must be respected. In other helicopters, it should be considered in your planning.

When using the towering takeoff or high-hover landing technique, be patient. Wait for solid references to appear before proceeding.

Practice landings and takeoffs using references that are inside the diameter of the rotor disc.

Training should be obtained from a qualified training pilot or flight instructor before using the techniques described here.

[koalaa119]

[

The aircraft in deep snow will likely rest on its belly parts among others, like I said, slow!

When lifting off, slow and easy, eyes out front, NOT in your mirror, thus maybe catching a rollover possiblity with your skids or bearpaws catching the snow crust.]

 

Although I have limited experience in deep snow here in Ontario, I agree completely with these comments. I have found on a number of occassions after dropping off passengers in deep snow that with the C of G change to more aft in the longranger with just the pilot, it becomes very important to come up very slowly. THis was especially true when I dropped of a heavy passenger who was sitting in the front. SLOW SLOW SLOW and maintain a good visual reference.

 

I have also had the experience in a longranger of not being able to land. I proceeded slowly into the snow with a good reference. As I settled I added slight forward cyclic to keep the snow clear of the tail. I had to stay in a hover because the snow reached the Pitot Tube and I was still sinking. WHen my three passengers lefft the a/c the first guy out was without snow shoes and he just about disappeared the second two learned from the first and even with the shoe's sank to there waists. Every place seems to have different consistency of snow depending on wind/temperature/ shade so I tend to go light into a hole for the first time. That way I don't have to worry about settling into something or not being able to hover above a cloud of snow.

 

Just my two cents.

[Mustache Gear]

If you do get into whiteout there is only one safe alternative. Drop the pole and land the thing...at that point is is essential to get on the ground. The result of some drivers pulling pich to get the **** out of there has been side slipping into a tree of touching a blade into the snow and riping the machine apart which has happend. I'd rather explain a hard landing and a rock throughe the undercarriage then have to explain a rollover. I don't know if all will agree with this but it's what I do and the one time it did happen I didn't have to do a hard landing inspection becaus there was lots of snow and it obsorbed the energy of the quick decent.

 

Fly safe

 

MG

[Max Continuous]

I'm not so sure about that MG. If one has screwed up and gotten oneself into whiteout,how can you be sure your not drifting anyway. Sounds like a good way to roll the machine over.

If it "works" for you ..fine but it sounds like you got REALLY lucky.

Never land in powdery snow without references. The closer to the A/C the better. A shrub in the chin bubble is perfect. NEVER land in the middle of a frozen lake or snow covered field. If you feel you must...look for a game or ski-doo trail,something packed.

Having the landing lights full on sometimes is a help as it will define the snow in close to the machine.

Make sure you pack the machine through the crust since the deeper you are the more stable the machine will sit.

It also won't settle onto a customers leg when they are out tramping around the skids.

Just my 2 cents.

MC

[mountainflier]

Thanks everyone for the great tips!!! I will certainly take them into account on my first checkride for snow ops. Any other tips are certainly welcome.

 

Has anyone been concerned about or had to straighten out belly antennae or a mirror after a snow landing - after you got back to base of course. I would think that even mildly packed snow can turn them into pretzels or at least push them over. Or perhaps... the sllllllloooooowness of the landing protects them.

 

Thanks again!

[gwk]

Weeeellll, since you asked, I,ll pass on an embarassing incident that happened to me in Blue River, heliskiing many years ago.

I was in a an AS350, it was snowing heavy, and I was coming in at the bottom of a run for a shut down and wait. I pulled in to a draw and edged over to the side, with the nose towards a tree for reference. It was white and dull, with a heavy overcast and heavy snow, and I drove the Astar in to the snow with a bit of forward momentum to set the skids, and then as I gently let down on collective, there was a horrible crunching, crackling sound from under the nose.

I pulled up enough collective to go light on the skids and sat there, trying to distinguish what I broke, and what caused that horrble noise. I thought that it would not be wise to fly away, as I did not know what damage I had done, so I eased back down on the collective, only to hear that horrible noise again. I thought , well, time to do damage assessment, and shut down the machine, and got out.

Weelll, I had poked the HF antenae into the snow right in front of me, visulize a big mogul right in front of the nose, but because the light was so flat, I could not see the snow was so high in front of me. When I dropped collective to set the machine, I ripped the mounting bracket out of the nose as the heli setteled on to the back of the skids, remember, I drove the heli into the spot to keep ahead of the snowball, and thus the nose was pointing down some.

I disconected the antanae lead, put the antenae and bracket in the tailboom, told the guide and skiers we were done for the day, and flew home with the guides down filled jacket stuffed in the hole from the inside out.

I did everiything as I was taught, and as I had been doing for several years prior to that incident, but, Murphy caught me out. My only defence in all this, was to ask, who ever mounted the HF antenae on the nose must have never thought about the hazards of deep snow.

 

One more thing to think about out there as we try to do our best.

Fly safe, and Happy Holidays where ever you are for them.

[Fenestron]

and KM did a great job of fixing said hole on site..... :up:

[skywrench1]

The aircraft in deep snow will likely rest on its belly parts among others, like I said, slow! In an Astar ensure your swing isn't pinned agianst your fuel drain

 

 

Also make sure you don't drive that cargo swing into the belly panel, it makes for an interesting conversation usually about the expense of the repair and how much INSERT LIQUOR OF CHOICE it will really take to slake your engineer's thirst