Bell 206 - Common errors, performance, handling & C of G characteristics...
 

For the benefit of people who are 206 rated with low hours on type, or interested in becoming rated.....

Could those of you with vast hours experience on type suggest common things to watch out for that could catch a less experienced pilot out? with regards to the start, loading & C of G, any handing characteristics (VRS, limited power checks, loss of TRE, Blade sailing etc... ).

One example that I recently read is that if you were to accidentally do the throttle full and free travel check with the fuel pumps & batt on, then the residual fuel in the chamber on start would be sufficient to lead to a hot start. Or that the time that might catch you out with a hot start is the second spike on the TOT as opposed to the primary run up... And ensuring before start that the batter power is sufficient to keep the starter motoring until approx 60% N1 (is there a way or if in doubt use a GPU). I vaguely remember somebody telling me that the governor can behave in slightly unexpected ways in a peddle turn, and that if your not careful it may close the throttle in a right hand peddle turn to maintain rpm relative to the fuselage, then droop the rpm when stopping the turn as the turbine is slow to spool up again (unlike the piston ships)....

Anything tips, or instructional points that over the years you has helped you to fly the aircraft safely and without incident, that are not necessarily stated in the manual or checklists :ok:

Much appreciated, Aucky

I don't have a lot of time in the 206, but at one time (not anymore) I would double check that the throttle was closed (by opening it) before starting with the battery on. I rarely started it with boost pumps on. I never had a problem, but I have heard it could light off when you hit the starter. I (knock on wood) have never hot started, but been around plenty. The only time I saw damage was when it was started with the throttle open. You can save it if you're quick, but mess up and you'll have some big bills coming! You will notice a weak battery right away as it winds up slowly and the igniters don't make their rapid clicking sound. If in doubt, get a cart. Be careful with pedal inputs at high power settings. It's easy to overtorque if you're not careful.

How do you manage that? The latest I heard from Bell was to not pull the CB's on shutdown----on the L4 we use the fuel valve to disconnect the boost pump from the battery......ergo, with the fuel valve open---the boost pumps will be running.

I ALWAYS do a full throttle check with battery, fuel valve on etc---never hjad a problem with hot starting.

You can do whatever you like with the throttle, boost pumps, fuel valve etc BEFORE hitting the starter button, and it won't matter a rat's. All the boost pumps do is provide pressure up to the engine-driven pump. Nothing gets past that pump until it is running.
When you hit the starter and the N1 turns and the engine-driven fuel pump starts to push fuel into the engine, that is when your ducks should be in line.

Ensure the throttle is OFF when you hit the starter - no airflow through the engine would mean an awfully hot and expensive start if the throttle is open from the first rotation.
At 12-15% depending on temperature, open throttle to IDLE, it should light off.
It is possible to take the throttle all the way open at this stage, the N1 FCU is only concerned with getting the engine to idle RPM of 58% self-sustaining, but if it then sees that the throttle is anywhere but at idle, it will pour the fuel in and away goes the temperature. So, keep it at idle until it settles at 61%.
Of course you can start without the boost pumps on. You only need them above 6000'pa to push the fuel to the engine, because the atmospheric pressure is too low for the engine to suck hard enough.

The governor doesn't "close the throttle" as such, and it would need to be a rapid pedal turn to get such a result. There is less torque required to yaw right than to yaw left, and it is possible, if you are near your torque limits, to get a spike when stopping a right pedal turn, as the torque demands increase quickly.

CG in a B206? Very hard to get out of cg, unless you have 2 real porkers in the front seat and nothing else.

The 206L is another story, having a longer arm to play with, and movable fuel cg as it burns down. Devise yourself a simple Excel prog to sort this, or download an app.

An excellent start thanks guys, all useful info :ok:

Almost every 206 I get into has the boost pump breakers pulled when I get in it. Old habits die hard, I guess. And every checklist I've seen checks the throttle before the battery is turned on, but often a big red placard on the panel saying:CHECK THROTTLE CLOSED BEFORE ENGAGING STARTER. I've had my hand slapped for checking the throttle one last time by opening it with battery and boost pumps on. Not following the checklist!:= I prefer the old way because if you leave the boost pump breakers in with the fuel valve on: dead battery if you leave it too long. The left boost pump will run with the fuel valve on and the battery off.

Here is a link to an Allison Service Letter previously posted on the 206 thread which provides lots of useful on starting a 250-C20:

http://fireheli.com/Files/allisonstart.pdf

watch your VNE, especially if you have air con installed. VNE goes to S*** over 3000 lbs and it doesn't take too much to get it there.

just to mention few.

becoming a 206 pilot you will also become a 100% guy ( meaning you will spend lot of time with TQ near the red line).

if the **** hits the fan, the 206 is not bad place to be in compaired to some other types, the high inertia rotor is very forgiving.

dont try extreme aerobatics, like rolling or loop :E

If you need to start in high wind it is safer to point the nose so wind is at 30° right of nose rather than having blade/tailboom kissing each other (those blades love to sail)

For 206 L3 if hot and high you can easily get out left pedal before other pwr limits

For L types load the rear seats always before mid seats, with full load ist often front heavy, to front heavy means your autoflare will be more interesting than normaly, put the fat guys in the rear seats.

If heavy for a confind area and mountain landing, a good pratice (at least while you are getting more familiar with its perfomance) do high hover pwr check, to see how much T/Q you need to hover, if dose not hover near full blast then you might consider some alternatives.

and for heavy, hovering and take-offs be patient and give the rotor a little time cath up rpm at 100%TQ.

and well tracked and balanced (Long Rangers especially) should be very smooth in the air, if not in might need some tracking of the rotor

have fun, fly safe

Before going anywhere near to starting make sure you know which fuel system you have….Bendix or CECO.

I have personally only ever flown aircraft with the 'Crack and back' bendix system, is that more common than the alternative with manual fuel flow modulation?

edit: for anyone who is unsure of the differences they are explained in this thread http://www.pprune.org/rotorheads/154...-throttle.html

The CECO is way too expensive to maintain these days, so the Bendix is more common

Phil

Lets see if we can confuse Aucky even more! I have been taught to start a C20W (Enstrom 480) with Bendix by opening the throttle (at 12- 15% N1) just to light off (not to or past the idle stop) and then just a tiny bit more to avoid flame out (still not to or past the idle stop). The reason I was given for this is to allow the fuel to be shut off instantly without releasing the idle stop button if the need should arise. Done it this way for years with no problems. Depending on the way the throttle is rigged, one might need to go past the idle stop to get light off, but in the 4-5 480's I have flown this was never the case. Dont know if this might apply to the 206 as I have no 206 time. :bored:

EN48 your description is spot on. I've always taught students to adopt this technique.. that way you are always on the safer side whatever the fuel system.

There are a million different techniques for starting 206's, depending on so many things (location of starter button, stiffness of throttle, etc.). You'll quickly learn which technique works for you. Yes, Bell says that c.b.'s are not to be used as switches, and therefore should always be in, but many, many, many pilots start a 206 with the Caution and boost pump breakers out. Reality: IT DOES NOT MATTER. But do it by the book anyway ;)

On the other hand, do not sit there for 20 minutes with the battery on, the boost pumps pumping, the strobe light strobing, and the gyros humming while you go through the million-item pre-start checklist. The battery is way up in the nose, and the cables that go back to the starter are loooooooong. Can you say voltage drop? I knew you could. 206's do not have voltmeters, so you cannot predict how good your battery is before hitting the button.

When you roll it up to 100% for takeoff, *ALWAYS* hit the Caution Light Test button before pulling pitch. This will alert you to the fact that you forgot to push the Caution and boost pump circuit breakers in after starting the engine with them out. Trust me on this.

206B's hover a little nose-high when it's just you inside. 206L's hover a *LOT* nose high when it's just you, especially if you're a 170 pound skinny kid. With two people in the front seats a B-model will hover fairly level. (All models also hover a little left-skid low all the time.)

With two people onboard, be careful when hovering downwind. The cyclic will be back in your gut. And the bigger your gut, the further aft the cyclic will be. When air gets under that horizontal stab, it wants to lift the tail big time. Don't say I didn't warn you.

Do an actual c.g. calculation and see how much you can carry in the baggage compartment when you're solo. Your "most-aft c.g." does not include having passengers onboard. Some day you WILL find yourself in a situation where someone wants you to carry a big, heavy, oily something and you don't want it on the back seats or on the floor. They'll ask if they can put it the baggage and you'll go, "Derrrrrr..." Easy solution: Find out now.

Finally, use some friggin' cyclic friction! The 206 pre-takeoff checklist only calls for the friction to be "set as desired." Many pilots take it completely off, which in most 206's give you an extremely sloppy cyclic. Put just enough friction on to give the cyclic some "drag." Otherwise you'll be making all kinds of extraneous and unnecessary inputs as the fuselage gets jostled around in the wind. (The fuselage will react to a smaller gust of wind than will that big, heavy rotor. And if the rotor doesn't move, the fuselage *will* come back without you having to make it.) Even *tiny* cyclic movements impart a "roughness" to the ride that is noticeable to the passengers even if it is not noticeable to you. Every 206 pilot thinks *he* is the smoothest guy to ever strap on a 206 since 1966. Trust me on this. Think about it: If you move the cyclic even 1/8th of an inch when it doesn't need to be moved, the swashplate *will* move a proportionate amount. If the swashplate moves, the rotor *will* move. Now you've just introduced a little PIO. And no matter what you think (or what you've been told), you CANNOT hold the cyclic steady enough with zero friction. Bottom line: Use a little cyclic friction. You'll look like a better pilot than you actually are - unless the air is glass-smooth.

DO NOT PARK DOWNWIND!!! As soon as a passenger pops the door open (and they will, even if you told them not to), they will lose their grip on it and the door will come around and slap a) the front door, or b) the bubble. Breaking any of the "glass" on a 206 is an inconvenient, expensive proposition. Those wimpy straps and/or little hydraulic struts are not guaranteed to keep the door from coming around. For loading and unloading, don't set down downwind. Don't say I didn't warn you.

Finally, leave the anti-collision light switch on ALL THE TIME. This way, when you shut down and you're in the FBO enjoying a nice cup of coffee, you can look admiringly out at your JetRanger and go, "Damn, I left the battery on. Again." Don't say I didn't warn you.

Well ... maybe it does matter - not with respect to the operation of the acft, but because CB's are not designed for frequent operation such as a switch might see. May compromise the functionality of the CB in time. :( You can do it but its not a great idea.

Ditto on the anti-coll, FH1100, though I've applied the practice to every type I've flown!

An old hand once told me the most important thing about a 206 is to know how far you can f**k it up and still save it.....! :E

22

When your in a brand new aircraft then I agree with the statement regarding cbs are not switches, but in the real world of old jetboxes with batteries and turbines that have seen better days, conserving battery power is essential. I also think it comes from the training and students sitting in the aircraft running down the battery for 20 minuets before hitting the start button, so instructors would pull the cbs and therefor the newbie pilots would continue to do this for ever more...but that's just my opinion for what it's worth.

I see what you mean. But using the CB's as switches involves a tradeoff. Doesnt the 206 have switches for the boost/xfer pumps? I am flying a 407 which has these switches and just assumed the 206 was similar.

FH knows of what he speaks! Definitely take note of those comments followed by "Trust Me on this!"

I would add never....never....never...never hit the starter button until you can see both blade tips and have your grubby mitt on the blade tie down. Trust me on this!

Also....if the aircraft is heavy....torque, Temp, or N-1....or any combination of the three are at max.....don't be stomping any pedals. Be as light and steady on yer toes as you can be.....else you shall have need to chat with the Engineers and perhaps the Boss Fellah.

Also....never carry yer fat wallet in your hindend pockets....it will give you a crook roll attitude and lumbago. Jet Ranger seats are a crime against Humanity. If you are required to fly them for extended periods of time...say...anything over about five minutes....invest in some Oregon Aero seat cushions or retain a first class Chiropracter.