History Behind "Clear Prop!" ?

[Sunken_Lunken]

I've been curious about the practice of yelling "clear prop" before firing one up. I know one should visually ensure nobody is near a prop, and I think it's a good idea to yell (in case you can't see the clown that's trying to re-chock your nosewheel as you get in, and the fool is still crouched down to avoid being seen).

Years ago (before I started training), I flew as a pax in a C-172. It was early morning, and we knew we were the only ones around. The pilot turned to us before he shouted "clear" and said, "This will seem silly since nobody else is around, but it's somehting we have to do".

I haven't seen this in the regs, and I don't remember it being in the AIM either. Is this just a good practice that has been handed down through the years? My guess is that it originated in the days of the big radials and tailwheels, when you could not see from the cockpit if someone were standing near the 13-foot Hamilton Standards.

Anyone have any insight?

 

[CUEBOAT]

I think that I've either been told or read it somewhere that it has to something to do with hand proping an airplane.

 

[Ralgha]

If you've seen the effects of being hit by a prop, you wouldn't be asking this question. Unfortunatly I can't find any photographs online to show you.

 

[Lead Sled]

FWIW, I once flew with a British pilot who insisted on calling "Clear the bloody airscrew!"

 

[TEXAN AVIATOR]

"Clear the bloody airscrew!"

Haha, I think I've just read my new phrase, I like that.

 

[350DRIVER]

If you've seen the effects of being hit by a prop, you wouldn't be asking this question. Unfortunatly I can't find any photographs online to show you.

I can tell you that it is not a very pretty scene at all... knew a guy that took a prop strike to the right side of his head. He survived after a 3 month long coma and a few surgeries to stop swelling and bleeding of the brain..

3 5 0

 

[CDVdriver]

It's part of a tradition handed down through the years,probably did start in the time of the big radials and tailwheels. Still necessary though, not only do aiplanes have a lot of blind spots, you also want to warn anybody that might be in shouting distance, yes I shout...
On a busy ramp with people walking about ,preflighting ,refueling ,whatever it is common courtesy to give one last warning to prevent people from walking either in front or right behind your airplane as you fire up.
Still scares the sh*t out of me if somebody fires up right next to me without warning.
And props do kill obviously..

 

[Lead Sled]

Personally, I think that it's just a quaint custom that serves no real purpose today - kind of like wearing a neck tie. If you're sitting in the front seat of a big radial engined taildragger and have to do S-turns to get to the runway that's one thing. If you're sitting in a Cherokee and can't see if anyone is walking around the prop you're not paying attention and you probably shouldn't be flying. Turning on the beacon or strobe prior to start will be much more effective.

One of my personal pet peeves is doing things the way they used to do it "way back when" just because that was the way my old gray haired instructor taught me. A couple other examples...

A few years ago I was giving a guy a combination BFR and instrument competency check in his Cessna 310. When he did the runup he cycled the props at least 3 or 4 times. When I asked him why so many times he told me that that was the way he had been taught. When we got back to the office I showed him in the flight manual where it was only necessary to do it once - to check the prop governor then continue on into feather. It turned out that his instructor had flown B-24's during WWII. It was necessary to do that on those big radials to flush the cold oil out of the propellor hubs. The problem was, the old instructor had never bothered to read the 310's POH. Old habits die hard. It's not that it's a big deal, you probably won't hurt anything doing things that way, but all it shows is that you haven't read or paid attention to what is written in the POH.

Another thing that I occassionally see is jet pilots who insist on hanging on to the power levers after power is set and you've accelerated past V1. Hanging on to the throttles- for "dear life" is not a bad thing, but again a lot of it comes from the old radial days - some of those big engines had a propensity to backfire back through the carborator. When that happened it would slam the butterfly shut and take the throttle along for the ride. Also, those big engines were known for their vibrating - which also had a tendency to walk the throttles back. With today's engines, it's not that big a deal. Like I said, with turbine engines the drill is to remove your hands from the power levers once you have achieved V1 - it's too much of a temptation to retard them if something untowards were to happen above that speed.

Lead Sled

 

[Sunken_Lunken]

If you've seen the effects of being hit by a prop, you wouldn't be asking this question.

Actually, I wasn't questioning the procedure, and I agree it should be shouted every time. I have always shouted clear, even if I'm "certain" I'm the only one on the ramp.

It just always seemed strange to me that it wasn't specifically addressed in the regs,AIM, etc. Of course there's the "careless or reckless operation" catch-all. I have always wondered why such a safety related practice is passed on by what seems to be oral tradition. Even though it's common sense to clear the area visually and verbally, I would expect to see it at least recommended somewhere (flight training book, advisory circular, etc.) rather than just rely on word of mouth.

 

[CDVdriver]

My point is that on a busy ramp you WILL NOT NOTICE a lil' red light come on and as far as I know even in a Cherokee you cannot see what is directly behind you.
I agree most of the time it is redundant ( because you checked before) but that is not a reason not to do it.
A multi layered system will always catch more mistakes then a procedure that relies on one check.

 

[350DRIVER]

Common sense will go a long way in this business.... Yelling "clear prop" in a single in between a Lear that just started up, a GV on the other side, and other loud aircraft on a busy ramp will do very little. It is much more important to use your head and eyes and make sure that no one is around or in the vicinity of the prop that could pose a potential safety risk prior to start up. I always found it somewhat amusing at the busier airports where rec/weekend pilots would simply yell "clear prop", not be heard due to other large & loud aircraft next to them, and proceed to start up without visually looking/scanning in all directions prior to starting the engine up. This will depend on the the airport that you are at, many of the larger airports that you may fly into will have a line service guy stand in front of your aircraft and wait until you have started the engine prior to walking away. Signature Flight Support was always very good about this no matter if you were flying a King Air 350, GV, or a C172. The noise levels on the ramps at IAD/JFK, etc, versus small training airports will be a world of difference.

3 5 0

 

[Lead Sled]

Maybe I came across as being against the practice. I'm not. I'm not trying to be flippant about it either. it just that it seems to me that if it's necessary to do it to be "safe" then why isn't it written or endorsed in the AIM or regulations? (Not that it has to appear in one of those to be a good idea.) Unfortunately, there are several prop stike accidents each and every year - but they seem to involve passengers deplaning into running engines, walking into tail rotors, line crew walking into props that are spooling down after shutdown, or pilots improperly attempting to hand-prop their engines. What I've yet to read is an accident report involving someone being injured because they were standing next to, behind, or in front of an aircraft while it was being started. I've been around airports for more years than I'd like to count and the drill hasn't changed - Yell "Clear The Prop" out the window or opened door, pause for a split second, then hit the starter. Like there would be enough time for anyone to get out of the way. If clearing the area "vocally" is necessary for operational safety why is the practice limited to single-engine aircraft? Why not light twins? Or helicopters? What about turboprops or even corporate jets? Like I said earlier, IMHO it's a quaint aeronautical custom that's been handed down since shortly after "self commencers" were added to aircraft. If you ever have an opportunity to fly in a restored antique make sure you take it. It will be a real "eye opener" for you guys - it's pretty hard to see anything from the back seat (pilot's seat) of most of those old biplanes. In the mean time, look outside, pay attention to what's going on around you. Turn on your lights prior to start. And treat that meat slicer in front of you (or at either side) with respect by clearing the area visually (and if you must, vocally), briefing your passengers, prior to approaching the airplane, about propellor safety and most importantly, never allow a passenger to get onboard or deplane an airplane with an engine running.

Lead Sled

 

[minus273]

Hey there,

Not sure about the 310, but I know that the AFM for the Seminole and Seneca says that the props should be cycled 3 times on the first flight of the day. The reason that alot of people get in that habit of doing this is that they fly flight training planes and treating every flight like the first flight of the day is not a bad thing. I know up in Canada when I flew there was a good thing as the oil gets cold real quick.

As for saying "Clear prop" I still say that whilst flying a twin or single, totally agree with the multi layered approach of beacon on, looking at the "inbred slicer and dicer" and finally shouting clear prop or left and right.

Anyways just my 2cents worth.

-273

 

[Ralgha]

Maybe I came across as being against the practice. I'm not. I'm not trying to be flippant about it either. it just that it seems to me that if it's necessary to do it to be "safe" then why isn't it written or endorsed in the AIM or regulations? (Not that it has to appear in one of those to be a good idea.) Unfortunately, there are several prop stike accidents each and every year - but they seem to involve passengers deplaning into running engines, walking into tail rotors, line crew walking into props that are spooling down after shutdown, or pilots improperly attempting to hand-prop their engines. What I've yet to read is an accident report involving someone being injured because they were standing next to, behind, or in front of an aircraft while it was being started. I've been around airports for more years than I'd like to count and the drill hasn't changed - Yell "Clear The Prop" out the window or opened door, pause for a split second, then hit the starter. Like there would be enough time for anyone to get out of the way. If clearing the area "vocally" is necessary for operational safety why is the practice limited to single-engine aircraft? Why not light twins? Or helicopters? What about turboprops or even corporate jets? Like I said earlier, IMHO it's a quaint aeronautical custom that's been handed down since shortly after "self commencers" were added to aircraft. If you ever have an opportunity to fly in a restored antique make sure you take it. It will be a real "eye opener" for you guys - it's pretty hard to see anything from the back seat (pilot's seat) of most of those old biplanes. In the mean time, look outside, pay attention to what's going on around you. Turn on your lights prior to start. And treat that meat slicer in front of you (or at either side) with respect by clearing the area visually (and if you must, vocally), briefing your passengers, prior to approaching the airplane, about propellor safety and most importantly, never allow a passenger to get onboard or deplane an airplane with an engine running.

Lead Sled

I don't yell "clear" then start immediately. I look around, flip on the beacon, yell "clear", look around again, pause, then start, or something along those general lines.

I do the same thing in a twin, and the same thing in a T-6.

Granted most people do just yell it and throw the switch without thinking, and all it does is let the person in the way know they're going to die before they do.

 

[mattfish42]

Please, please, please, for the sake of me and everybody else who frequently find ourselves in close proximity to spinning propellers, don't teach that yelling "Clear!?" is quaint, antiquated, outmoded, useless, etc.!

My life could depend on you not screwing this up.

I might be working on the plane directly behind you, where you can't see so well, and would appreciate a few second's warning to secure anything likely to blow away. I might be walking back to the hangar for another tool, my attention on the airplane taxiing in at 45 knots who will probably try to run me over, and I might possibly miss your beacon that shines so brightly on a sunny day.

The proper way to start is this:
Complete your checklist. Look around. Turn the beacon on. Look around. If you see anybody outside on the ramp, open a door/window, ask him "Clear?!", then wait for his response. If he has been taught correctly, he will visually scan the area around your plane, give you a thumbs up, and call back "Prop clear!". If nobody is visible on the ramp, ask "Clear?!" anyway. Look around a couple seconds more. Start the engine.

Notice how much time is spent looking around outside. Probably the most common mistake in the whole process is yelling a "split-second" before start; or better yet, turning the key and yelling at the same time. Please, wait a few seconds, look around outside, give me time to get out from under the nosewheel where I was removing the chocks you forgot.

Rather than some charming relic handed down from yesteryear, this tradition is useful, professional, and courteous. What could you possibly gain by omitting it?