''Safety'' procedures

[PPRUNE FAN#1]

I know I usually don't usually initiate threads, but this one issue has been bothering me lately. In the "Priceless Tips" thread, one of the posters makes the suggestion of putting the blades of a two-blade helicopter at 90 degrees prior to starting. This has become a sort-of-accepted and fairly widespread practice that is done in the interest of "safety", of course. The theory being that you cannot start the ship with the MR blade tiedown on if the blade is at 90 degrees.

Hmm.

I laugh often, but never so heartily as when I see a well-meaning 206 pilot (especially a 206L pilot) who conscientiously pulls his main rotor blades out to 90 degrees, and then leaves the tiedown on the blade! instead of stowing it. Now there's a classic set-up.

There's something else. I don't know about your AFM, but mine says that the main rotor *must* be turning by 25% N1. If not, you have a problem that must be investigated. For pilots who put their blades at 90 degrees, I wonder how they verify that the MR blades (i.e. the N2 turbine) is turning by 25% N1? I guess my bigger question is: Why do some pilots feel that they can ignore a fairly important checklist item in the name of convenience?

This is not a silly or inconsequential point. I used to fly one particular ship regularly. I took a couple of days off, and a pilot filled in for me. When I got back, on my first start the blade didn't even begin to turn until 30% N1. I shut down and walked the blade around and around backward in a futile attempt to "free-up" the lab seals on the N2 turbine wheels. We ended up changing the turbine because the fill-in pilot was "short-cooling" the engine. I never would have known this if I was in the habit of parking the blades crossways prior to the start. Silly, dangerous me.

Yes, yes, you'll probably discover any binding of the N2 if you pull the blade backward as you untie, but the dang ol' 206B has a MR tiedown setup that leads you into moving the blade in the direction of rotation during the untying process.

To my way of "thinking," it is better to glance up at the blade for a moment during the start to verify that it is indeed turning by the proper rpm. In this way, you verify two checklist items: 1) that your N2 is not locking up, and 2) that you've untied the main rotor. Focusing too intently on the TOT gauge is not healthy. There's a lot going on during the start, and you cannot become tunnel-visioned.

Our three and four-blade aircraft all use at least one tiedown on the main rotor blades. So on an AS-350, say, seeing no blade above you is no guarantee that the tiedowns are off. Similar with a BO105.

I believe that the "blades at 90 degrees" crowd are misguided, and that they've come up with the wrong solution to the problem of leaving the main rotor tiedown on.

Your thoughts?

[212man]

"Focusing too intently on the TOT gauge is not healthy. There's a lot going on during the start, and you cannot become tunnel-visioned."

I think you answered your own question; it is possible to monitor all sorts of things during a start, even blades that aren't in your immediate 12 o'clock field of focus!

Personally, on the 212 I preferred the 2/7 position, as it proves the blades (including TR) rotate, is easy to to unclip the tie down at the low point, and keeps the front blade well within view during the start. It is also where we would orientate the wind for a high wind start (2 o'clock).

Which reminds me of a pet hate: people who jump up to grab the forward blade to attach the tie down, and then bring it down with a smart smack to the mast and lots of blade 'twanging.' Yeurch!

Be gentle with me in your response: I haven't stopped counting my hours yet!

:ok:

[EESDL]

I was under the impression that one of the main reasons for starting with the blades in the 3-9 position was so you didn't cook the blades on start.......or is that complete ar5e as well?

[212man]

I doubt it; how many 2 bladed helicopters can start with the rotor brake on. It's more of a 76 type consideration where you need the blades at 45 degrees with a rotor brake on start.

[Steve76]

PP#1 is correct. It is just a rule to prevent a lack of thinking.

Starting with the blades tied down is easily done but it indicates a lack of awareness and thought.

I like to have the 2 bladed turbine machines at 11/5 o'clock positions since I figure they will be moving positively through the ash and heat coming out of the turbine during the start. Plus I have to clean them, so less ash means less effort...

[flyer43]

Focusing too intently on the TOT gauge is not healthy

Focusing on anything too intently is not healthy, but let your eyes wander too far from the TOT during the crucial part of the wind up and you might even burn your first engine out.....

I'm with 212man regarding the 2/7 (although I believe that should really be 2/8 !!) as it helps keep everything within your scan, especially if you use your peripheral vision properly.

[PPRUNE FAN#1]

flyer43:I'm with 212man regarding the 2/7 (although I believe that should really be 2/8 !!)I've had to sweep a blade a ways to get in balance before, but 2/7 sounds awfully extreme.

212man:Which reminds me of a pet hate: people who jump up to grab the forward blade to attach the tie down, and then bring it down with a smart smack to the mast and lots of blade 'twanging.' Yeurch!...Which reminds me of a question I've had since I was a little baby helicopter pilot: Why *doesn't* a 212 have droop stops?

[SASless]

The inherent advantage to 3/9 is one can see both ends of the blades....thus the liklihood of missing a tiedown left hanging is decreased as opposed to either the 2/7 or 2/8 method. Also...if you cannot see the blade turning by the stated RPM using any position for start you have more problems than blade tie downs. Also...if you recall...I said one should visually account for that tie down......and never...never leave the tie down hanging from a blade.

I can assure you...when the accident chain starts with the 2/7 or 2/8 position...it will also include a tiedown left hanging on the out of sight blade.....and as you glance at the now turning blade what will immediately catch your attention is the now visible tie down swinging well out to nicely accomodate snagging the faster turning tail rotor.

Manually turning the blade a bit also allows one to listen for any unusual noises...which is not a bad thing either.

212man....I cannot wait for you to start flying real helicopters with many blades....you will have to start wearing sandals to be able to keep track of all those numbers. Is that Gulder working on you today by chance? Not that you would be inclined to be celebrating your pending parole.

[flyer43]

The inherent advantage to 3/9 is one can see both ends of the blades....thus the liklihood of missing a tiedown left hanging is decreased as opposed to either the 2/7 or 2/8 method.
Absolutely true, but, as SASless says, the key requirement for any of these methods is that the pilot should ACTUALLY check to see whether he (or she) has removed the tie down correctly. (The same goes for engine intake blanks and flotation bottle safety pins!!) By moving your head around a bit you can see both blades of most two bladed machines in the 2/8 position.

During my student days, and again during my time as a CPL(H) instructor, the idea of placing the blades at the 3/9 position was drummed into me by the Chief Instructor. Pity he didn't always do the double-checking bit himself as one day he started a 206 with the tie-down on, even though the blades were in the 3/9 position!! Thankfully for him, the tie-down was on the initially forward going blade and the bright red tell-tale flag attracted his attention just as the engine lit. On this occasion the tie down did not snag the tail rotor, but it was pretty damn close.

As for manually turning the blade, I used to do just that - but walked the long way around in order to listen for any noises.

[PPRUNE FAN#1]

SASless:The inherent advantage to 3/9 is one can see both ends of the blades....thus the liklihood of missing a tiedown left hanging is decreased as opposed to either the 2/7 or 2/8 method. Point taken! I hadn't really considered the ability to check both ends of the blades before punching the button.Also...if you cannot see the blade turning by the stated RPM using any position for start you have more problems than blade tie downs.Well that's kind of my point. If you can't see the blade, how do you KNOW if it's not turning by 25%? And is that important? Also...if you recall...I said one should visually account for that tie down......and never...never leave the tie down hanging from a blade.
flyer43:During my student days, and again during my time as a CPL(H) instructor, the idea of placing the blades at the 3/9 position was drummed into me by the Chief Instructor. Pity he didn't always do the double-checking bit himself as one day he started a 206 with the tie-down on, even though the blades were in the 3/9 position!! Still...the "9/3" procedure takes away the ability to do one of the checklist items, and is no substitute for good, solid procedures such as ensuring the tiedowns are off before climbing in. Then if you do that, it doesn't matter where you leave the blades.

One of my biggest fears in life is leaving the blades of a 206B at 11/5, getting it lit-off and seeing the big, red "PHI pole" tiedown gliding gracefully past my cockpit windows from right to left. No matter how quickly I shut her off and grabbed the brake, would it be quick enough? I rather doubt it. And I don't ever want to find out.

[[email protected]]

What is wrong with teaching pilots to do a proper pre-flight walkround? If people are missing obvious things like red tie downs, what else are they forgetting to check beofre they get in and start-up?

[BigMike]

This is what I was taught. Untie blades and walk backwards to the front (lab-seal, listening for excessive turbine rub or lockup. Had this twice on 500's), unhook tie-down with blades at 2/8(206). Put tie-down in side pocket on pilots door and check they are there again pre start. Sure watch TOT and blades turning by 25% but as I had drummed into me, check you have raising oil pressure. There IS alot going on when you crank it . It all comes back to a good walk round pre-start I guess.

Cheers BigMike

[The Nr Fairy]

Not only does looking at the blades before pressing the tit help you realise if the tiedowns are still on, it lets you see the two "agriculture students" near the aircraft who weren't there when you started your pre-start checks and are taking pictures of each other against the aircraft.

Cost me a few minutes to stop, get out, ask them to move, get back in, get settled and carry on - but I think they'd have got the message about moving anyway when I started up !

[ShyTorque]

Hadn't thought about this problem too much before as I haven't flown a two blade'er, apart from my one and only go in a Robbo.

However, may I suggest that this blade tie down on start problem could perhaps be prevented if a suitable reminder flag or placard was made up, to go inside the aircraft whenever the blade tie-down was used, perhaps hung on the controls or in the eye-line of the pilot over the engine instruments.

Whilst I worked on a police air support unit, we had a few scares with the inside transparencies misting up just as the aircraft was transitioned away on a no-notice callout. This is obviously extremely dangerous, especially at night. We subsequently obtained a compact ceramic element electric fan heater, which was left running in the aircraft when necessary to keep it warmed up inside. That completely alleviated the misting problem but there was a danger that the aircraft might get airborne with electric cable still attached. We made a large warning placard which was hung on the rotor brake to prevent that (allied with a suitable SOP to mandate that the placard was always placed first and removed last and mandated a clear responsibility for the pilot to check that the heater and cable had been removed).

Could this work in this instance?

One other thing that did occur to me about this. Placing the blades at 90 degrees to the aircraft should ensure that when the engine is started, there will be sufficient clearance between them and the adjacent aircraft - which would have prevented a ground accident that occurred in the north of England recently...

[Sailor Vee]

One of the reasons for having the blades across on the 205 was that with the up tilted exhaust (anti IR missiles), you could easily cook a blade during start, same applied to the 206 with ‘bunny ear’ exhausts. Never had the problem with 212s or 214s.

Why not have a small can, painted red, which you can place over the cyclic when the tie-down is in place. The tie-down can go in the tin when removed and stowed in the boot. However, I’m with the crab on this one, why not just make sure your walk-round is a good one, (called AIRMANSHIP!!):ok:

[albatross]

I am against another placard, flag, flashing light, flare or warning gun.

I maintain that there are only two places for a tiedown.
On the blade and tied down or off the blade and under the pilots seat.

Do a quick clockwise walk around.
Pre start Checklists complete ECT. And whether solo or two pilot.
I still use a patter I was taught years ago in a 212.

Finger moves from boost pump switch to fuel valve to Gov switch
Onwards to voltmeter to blade
"Power" (Volts)
"Pressure" (Fuel)
"Tiedown off" (Look at Blades and tiedown under seat)
"Starting 1"
Engage starter
"Voltage recovering"
"Oil pressure"
"N1 12%"
"Throttle open"
"Blade turning"
"ITT"

58% Release Starter
"Hyd. Press"
"Trans Press."
"CB Press"
"61 N1"
"70 N1"
"Gen On"
"Volts /Amps"

Throttle to >85% Nr

Back to boost pump
Fuel valve
Gov switch
To NR Gauge
'Power" (Volts / Amps)
"Pressure"
"NR >85"
"Starting 2"
Engage Starter
"300 Amps"
"Oil Pressure"
"12% N1"
Open throttle
"ITT"
"58 N1"
Release Starter
Join N2s
"70%N1"
"Gen on"

"Post start checks please"

Yer on yer way. With slight mods works on most any helicopter.


Of course my fellow crew think I am mumbling to myself and need a good shrink. They may be right but it works for me.

[rotorspeed]

As ever the issue is one of balancing the risks. Many years ago I felt the numbing pain of trying to start a 206 with blade tie down still on. Thankfully no damage, but thereafter it was always around 2/8, where the forward blade is within reasonable scan.

If the blades are not at 6/12 and are not turning approaching 25% at least you know it cannot be because the tie down is on, and must be another cause.

Another point is that if you leave the blades at 6/12 there is the chance of blade/tail boom contact damage if another heli causes excessive downdraft, as happened to a R22 in the UK a year or two ago. There is another thread on it somewhere.

No question vigilant walk round crucial. Biggest risk? Interruptions! Phone rings, someone shouts, pax arrive and chat. Focus till it's done. Again, like many I dare say, have learnt from the mistakes!

[212man]

The 2/7 position is good for checking the drag brace is still attached!

I agree that it doesn't matter what else you do, a conscientious walk round followed by a visual check that the tie down is under your seat is the answer.

[flyer43]

...Which reminds me of a question I've had since I was a little baby helicopter pilot: Why *doesn't* a 212 have droop stops?

Droop Stops are all well and good, provided they are working properly. If not, we end up back to the start of this thread "Safety" Procedures. As you are obviously used to helis with droop stops fitted, you might have experienced a droop stop failure during shut down. How did you find out first? Was it when the ramp handler signalled that the stops had failed, did you look in the side mirrors (if fitted) and check, or was it when one of the blades sailed past the window several feet lower than the others?
Again we get back to the good old "airmanship" principles, or CRM as it is now known. As with the tie down, unless you use your eyes to verify everything that should be checked, then something will jump out and bite.....

[SASless]

The answer to your question Crab.....Pilots are human beings and thus are fallible.

You ever been interrupted in the middle of a preflight....or run-up and missed something? If you have any experience you indeed have.

Ever skipped a line or two on a printed checklist following some interruption....again....if you have been flying very long...the answer is YES.

What we are talking about is a simple, mechanical, non-thinking, habit pattern that can prevent an UH OH from happening.

A simple thing like taking a wander all the way around the aircraft immediately before climbing into it....after doing a preflight...just to make sure.

Doing a hover check before all takeoffs.... or doing a clearing turn.....

Humans are interesting creatures....but are creatures of habit. Disturb one of those habits and watch the mistakes occur.

Ever sat in the rear of a simulator and watched aircrew at work? It is an excellent learning venue for the observer (sim instructor).