Flying into Smoke

[Peter-RB]

Whilst looking at the latest piccies in the Views around the World etc, I was drawn with the seeming peril that the Air Crane dropping water onto a fire could be in, and this question arises from that last picture,

At what point does the engine loose power due to inhaling more smoke than pure fresh air, and does this type of flying into smoke ever cause any known sink or power loss!

And to those of you who do such things, I salute your skill and your Bravery!

New years eve and idle minds!!


Happy new year to all of my fellow Ppruners

Peter R-B
Vfrpilotpb

[organ donor]

Flying into the smoke is not a great idea. The problem with smoke is the obvious loss of visibility, the other thing is it is full of burning debris and tends to be very hot, so its not great for the engine. It can definitely bark at you to let you know its not happy, and the heli is covered in muck when you go back to base. I try avoid smoke like crazy, but many will go in to get a better line.

ps. Just had a look at the picture and he doesn't seem to be in the smoke really.

[catseye]

Peter-RB
Ops in smoke can have some interesting moments.

- anything that uses bleed air can be a problem eg fuel control units ( maybe CECO, its been a while)
- blade and compressor components performance deteriorates
- mix in some salt spray on a coastal site and it can get nasty.

Most concientious people will wash machines and do compressor washes at regular intervals and in some cases this comes down to daily.

Biggest direct risk is " things " appearing and disappearing in the smoke that are hard to make out which direction they are going in. Loss of horizon also knocks some people around, can increase airsickness for observers and incendiary bombers in particular.

The Eye.

[NickLappos]

The actual concentration of matter in smoky air is usually quite small, and not always an issue. Salt air and heavy air pollution (like the gooey substance in the air around paper mills) are usually much more of an issue for turbines.

You can tell if things are going bad by looking at the front frame and first stage blades for particulate matter build-up after a few hours as well as at the PC discharge ports around the fuel control where the gum or dust particulates will show up quickly.

[Hiro Protagonist]

Nick said,
The actual concentration of matter in smoky air is usually quite small, and not always an issue.
which is may true in smoke which has drifted far from a fire, but each of the white steaks on my window in this picture is where ash has struck and stuck.

http://farm2.static.flickr.com/1302/898129190_c37611ef48.jpg

When this photo was taken, I had only been orbiting this fire for approx. 10 minutes and probably only passed through the smoke a couple times (not the dense part in the picture mind you, but the more diffuse smoke further downwind - under the column).

When you work close in (doing buckets etc.) you get significantly more ash accumulation. Hurray for FDC filters.

[NickLappos]

Hiro,

We agree! Smoke can be heavy in particulate or light, and frankly, the visibility obscuration is not the way to tell. Usually, particles fall out of the smoke quickly, they are propelled by the heat and wind to stay aloft.

[ShyTorque]

Worst smoke I flew through whilst firebucketing had a whole lot of CS gas in it. We were trying to put out a building fire at a refugee camp while a riot was taking place and the local police "got just a bit carried away". :ugh:

At that point we had to give up as I was losing my vision and starting to choke.

Another hazard was birdstrike! The local hawks (some of them with 1 metre wingspans) used to fly around the grass / shrub fire looking for lizards and snakes that had got toasted.

We used to get very close to the flames at times but I was always concerned not to fly through oxygen depleted air, for obvious reasons. Some of the turbulence caused by the rapidly rising air could give us quite big jolts.

[jab]

Some guys I know were on a fire in a Mi-8 with a bucket on a belly hook. They were trying to do an upslope drop and inadvertently flew into thick, black smoke. Both engines proceeded to wind down with a corresponding drop in RRPM, height and airspeed. Apparently, clever ideas to resolve the uncomfortable situation were not forthcoming either.
The fire was in a pine plantation and fate was kind to them, they were aligned with the rows of trees and happened to be in the gap between rows. The fuselage was ploughing through the boughs while the blades were just above the trees. They were saved when they cleared the top of the ridge and managed to regain all the desired flying qualities, like RRPM and airspeed while diving down the slope.
Aside from some fresh dents in the fuselage and a need for new underwear, all appeared to be in order. To give you an idea how close they came, the bucket had to be cleared of pine needles which they had scooped up off the ground.
I have scared myself silly on fires when the smoke happened to be thicker than expected or hard, immovable objects loomed out of the gloom but I hope I never get as close as those guys did.

[Hiro Protagonist]

As a copilot I watched as two ships approached a very smoky area from opposite directions. Air-attack called everyone over to an active spot-fire that they really needed shut down. One of the ships was already in the rotation from nearest water source, while the other was coming from the opposite end of the fire - they couldn't see each 'cause of the smoke. I called out something like, "there are two helicopters about to enter the smoke at the spot in opposite directions." and watched them both break away... I don't know how close they might have come, but visibility in there was atrocious (http://www.pprune.org/forums/showpost.php?p=2588920&postcount=219).