Rocks and props

Invertago · Post by **Invertago** » Sun May 24, 2009 10:13 pm

Just recalling a thread about sweeping under props before start up... with all these rocks hitting props... where do the rocks go? If they become projectiles shouldn't we see more broken windows on the terminals and other aircraft? Kinda like when I hit a stone with my lawnmower and it takes out the window?

Tim · Post by **Tim** » Mon May 25, 2009 2:36 am

it doesn't have to be a 'rock' per se. even small pieces of loose dirt are enough to erode a prop, but they would be far too small to break a window. its the shear spead they hit the prop with (or the prop hits them) i guess

iflyforpie · Post by **iflyforpie** » Mon May 25, 2009 7:22 am

Had a poor Navajo go into the dirt after landing downwind on our strip. The plane was fine until the space-cadet flying it decided to rev the engines to get back to the tarmac. He toasted both props and managed to put a hole in the side of the nose while sending everyone who was watching this debacle running for cover from the hail of projectiles.

Another thing to watch for is operating off runways where they are towing gliders. The tow-rope usually drags some rocks over the button.

Cat Driver · Post by **Cat Driver** » Mon May 25, 2009 7:36 am

It is really simple:

You never use an RPM higher than normal idle when the airplane is stationary unless you are certain the area under your prop/s is free of loose debris.

When accelerating to taxi speed or for take off you very gently add power so as not to erode your props with debris picked up by the vortex caused by the prop/s.

On gravel runways one must accelerate smoothly so as to have sufficient forward movement to allow speed to build up as RPM increases this will help to keep ahead of any debris the prop/s pick up.

Bushav8er · Post by **Bushav8er** » Mon May 25, 2009 7:44 am

And keep moving, don't stop... and a favourite of mine, alluded to above, PAY Attention to people and things around you! When there is a choice, turn without blasting others. Your profession as a (professional) pilot doesn't end when the wheels are back on the ground!

V1RotateV2 · Post by **V1RotateV2** » Mon May 25, 2009 8:00 am

Bushav8er wrote:Your profession as a (professional) pilot doesn't end when the wheels are back on the ground!

Same goes for strobes and landing lights while taxiing around!

cessnafloatflyer · Post by **cessnafloatflyer** » Mon May 25, 2009 8:07 am

You never use an RPM higher than normal idle when the airplane is stationary unless you are certain the area under your prop/s is free of loose debris.

And in a seaplane in a tail wind, use even less! Water is just as bad or worse than rocks on props.

J31 · Post by **J31** » Mon May 25, 2009 9:32 am

While using all the tricks of the trade will minimize damage to the aircraft, stone and blade erosion on gravel is a “fact of life”. Learn and utilize all you can to reduce the damage but don’t sweat it too much. Smart operators budget for increased prop maintenance for gravel ops.

HS-748 2A · Post by **HS-748 2A** » Mon May 25, 2009 10:29 am

Bring it up as slow as possible, and then reduce power as soon the airplane moves if terrain allows.

Once had an captain on the 748 that coached his F.O.s to give a "quick little burst" when trying to get moving, instead of just bringing up the power as slow and smooth.

He said, "It's much better with a quick burst; get it over with.."

Needless to say, he caused alot of needless damage and we were a long time un-learning this "technique".

MAG1 · Post by **MAG1** » Mon May 25, 2009 1:40 pm

Also turn into wind on gravel and park downhill so it's easier to get going when you startup again.

AntiNakedMan · Post by **AntiNakedMan** » Mon May 25, 2009 1:48 pm

For making initial movement over gravel/rocks, I have always been taught and always practiced using a quick burst of power to get the aircraft moving. I have found that a slow and smooth application of power will pick up more rocks, expecially if you are not pointed into wind.

Just another canuck · Post by **Just another canuck** » Mon May 25, 2009 2:03 pm

I was always taught smooth application of power... hmmm. Funny how these two totally different practices are taught to each to be the best.

Making sure you park downhill is your best defense against the problem in the first place... IMHO.

If I was ever in a really bad spot or couldn't get moving, I just got a team of Papuans to give me a push.

chu me · Post by **chu me** » Mon May 25, 2009 2:47 pm

When you land, allow the a/c to roll out to the end and taxi back slowly (time and traffic permitting ), this allows you to arrive at the ramp with the cool down over and ready to shut down the engines when you come to a stop. I have seen too many hotshots land short and then taxi to the ramp only to have to spend three minutes in one spot waiting to cool down all the while dinging the props!! This method saves on props and brakes! Also, for those of you flying to Ft. Albany, Kash, Attiwapiskat, etc use the cement pads provided... believe it or not Air Creebec doesn't own them!!!! They are for public use !!! 1st come 1st serve!!!

rampking · Post by **rampking** » Mon May 25, 2009 4:59 pm

No trouble to tell you are operating Garretts!!!

King

Bushav8er · Post by **Bushav8er** » Mon May 25, 2009 6:12 pm

use the cement pads provided... believe it or not Air Creebec doesn't own them!!!! They are for public use !!! 1st come 1st serve!!!

1) Airmanship again - only if you need them. If you are a tail dragging low RPM piston and a turbine with low props is there too - Let them have the pad.
2) Only take the pad if its a drop and run - if you are spending more than 15 minutes there - leave it for others.

chu me · Post by **chu me** » Mon May 25, 2009 7:01 pm

Bushav8er wrote:
use the cement pads provided... believe it or not Air Creebec
doesn't own them!!!! They are for public use !!! 1st come 1st
serve!!!
1) Airmanship again - only if you need them. If you
are a tail dragging low RPM piston and a turbine with low props is
there too - Let them have the pad.
2) Only take the pad if its a drop and run - if you are spending more than 15 minutes there - leave it for others.

Good point. I just assumed that was understood.

Rudy · Post by **Rudy** » Mon May 25, 2009 7:10 pm

chu me wrote:believe it or not Air Creebec doesn't own them!!!!

A co-worker once had the locals on the coast trying to pull his aircraft off the pad by hand because 'this is a creebec airport.' Hahaha. Poor guy.

Bushav8er · Post by **Bushav8er** » Mon May 25, 2009 7:29 pm

Good point. I just assumed that was understood.

LOL - on this forum - Never Assume Anything

A co-worker once had the locals on the coast trying to pull his aircraft off the pad by hand because 'this is a creebec airport.' Hahaha. Poor guy.

Well, its still not a Creebec airport (YAT?) but it seems some communities treat them like that (wonder if said airline has 'paid extra' for this treatment)

Donald · Post by **Donald** » Mon May 25, 2009 9:08 pm

Bushav8er wrote:Well, its still not a Creebec airport (YAT?) but it seems some communities treat them like that (wonder if said airline has 'paid extra' for this treatment)

You'll find that silliness wherever you go, doesn't matter if it's Labrador, N Que, NWO, Prairies, NWT, etc etc. The local agents always carry on and throw a big fit that the local sched must be able to park on the pad, usually because that's where they always park. Tell them to stuff it, and then remind them that it's a federal offense to screw with someone's airplane.

The funny part is, you'll be in a Navajo and the sched will arrive in a Caravan. Who benefits from it more?

Invertago · Post by **Invertago** » Mon May 25, 2009 10:37 pm

LOL, I just asked for stories about where these rock projectiles go after they hit the props and everyone is telling me how to avoid damaging my props when I'm starting up etc lol. I know how to avoid picking up the crap....

Always before I shut down my engine, I go full power, do a 360 on the ramp and blow it clean so that when I start up there is nothing to hurt my prop

Just like I wash the plane by going diving VNE through rain showers

iflyforpie · Post by **iflyforpie** » Tue May 26, 2009 7:53 am

I told you one.

He toasted both props and managed to put a hole in the side of the nose while sending everyone who was watching this debacle running for cover from the hail of projectiles.

Now it's time to wash the plane and clean the ramp....

Cat Driver · Post by **Cat Driver** » Tue May 26, 2009 9:00 am

where do the rocks go? If they become projectiles shouldn't we see more broken windows on the terminals and other aircraft?

LOL, I just asked for stories about where these rock projectiles go after they hit the props and everyone is telling me how to avoid damaging my props when I'm starting up etc lol. I know how to avoid picking up the crap....

Best way for you to find out where the rocks go is buy yourself an airplane and hire a photographer with a high speed camera capable of filming at a speed that each frame can be stopped so you can examine what happens as the prop hits the rocks...

...then find a surface with lots of loose rocks and put the park brake on and start adding power until you hear the rocks being hit by the prop.......

.......that way you can determine if the rocks are smashed to little pieces or are projected somewhere in one piece.

Let us know what you find out about this very must know issue.

Invertago · Post by **Invertago** » Tue May 26, 2009 9:29 am

I have the camera can I borrow your plane?

Cat Driver · Post by **Cat Driver** » Tue May 26, 2009 9:43 am

I have the camera can I borrow your plane?

You really want an answer to that?

HS-748 2A · Post by **HS-748 2A** » Tue May 26, 2009 10:19 am

Anti Naked, maybe you were my captain in question?

Smooth application is the only way to go. I'm sure of that.

The static enertia of resting pebble is almost instantly overcome by the burst of air as the power comes up, and definately before the airplane gets a chance to move.

By jamming up the throttles, you overshoot the exact minimum required amount of thrust required to get the airplane rolling, thereby sucking up more gravel and shit than you would otherwise have to.

Cat Driver, what was your technique, back when you were allowed to fly in Canada?

(I thought I'd get the jump on that before you do; save you the trouble.)

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