Starting 206L4

[Nearly Retired]

Gomer's right: A lot of people think the CECO (Chandler-Evans) gave you a "modulated" start. They do not. They do allow *some* adjustment of the TOT, but it ain't much. It's certainly not modulated in the way the L-1/L-3/L-4 is.

 

And that's the difference between the 206B and 206L-1,3,4 series. In the B-model the fuel is pretty much On/Off. In the L-series the TOT is pilot-controlled.

 

In practice it really doesn't matter too much at what N1 speed you introduce fuel, as long as it's above 10% or so (with the N1 increasing at a rapid rate of course). Any 250-series engine will start okay if you do that - AS LONG AS - you've got a good battery. Don't ask me how I know.

 

Also, as Gomer said, if the TOT in either a B or an L tends to routinely go over the redline, call a mechanic and HAVE IT ADJUSTED. Because it's not right.

 

Quick story: I was working for PHI, flying an L-1 offshore, an aircraft in which I had (even then) a lot of flight time. Took a couple of days of workover on another offshore job. The crewchange for the pilots coincided with the crewchange for four field foremen in New Orleans. Bring four in, let them meet with their counterparts, then bring four out, dropping three in their fields along the way.

 

I did not have an opportunity to fly this particular ship before jumping in with the foremen. First time starting it. So, being cautious, I just crack the throttle open. BOOM! TOT goes for the roof. Ease it back and it signs off. Crack it open just an RCH and BOOM! Again the TOT goes for the roof. Cut if off again. Dammit! This went on for four cycles before I got the thing running. I'm sure all four foremen onboard were thinking, "Who's this noob?"

 

So we finally get out to the platform I'd be living on for the next three days. I got the mechanic and told him to turn the damn lightoff down. He was hesitant. "Uhh, that's the way the guys who fly it regularly like it," he said. Which is true - offshore you want fast starts to get the blades going quickly. But that was too hot. He didn't like it, but he turned it down for me. Probably turned it back up when I left :-/

[helipilotm]

Even with a CECO, you start a B the same way - roll the throttle to idle and watch it. You can supposedly modulate slightly from the idle position with a CECO, but I never had much luck with it. If the start isn't right when you roll to idle, get maintenance to adjust it. But I doubt there are many, if any, CECO fuel controls left in use. We used to have a number of them, and in practice there is no difference in starting. Run it up to 15%, roll the throttle to idle, press the idle detent to make sure you can roll the throttle off if necessary, and watch. Kill if if you have to.

See I learned something I've never flown one or seen one with a CECO. Good to know thanks fellas!

[aeroscout]

The intellistart system for the LR series is non modulated...

 

 

A new STC’d product from Honeywell/Altair is Intellistart Plus+. This system performs FADEC-like autostart and full HUMS monitoring for the Rolls-Royce Model 250-C20 and -C30 families of engines found on thousands of Bell 206s, MD 500s, and numerous other aircraft.

Last year, AlliedSignal bought Honeywell and took the Honeywell moniker. Before the purchase, AlliedSignal bought Bendix (manufacturer of the Bendix fuel controls and governors in most Rolls-Royce Model 250 engines), so Honeywell is now the keeper of the knowledge and data about fuel controls and governors for older non-FADEC engines.

These Bendix fuel controls and governors have tens of millions of proven flight hours and very rarely show signs of problems. With the Honeywell Intellistart Plus+, no changes in pilot procedures are required for starting or in flight operation. Intellistart Plus+ stops controlling the fuel flow as soon as the start cycle has ended (60% of N1 RPM). Only the HUMS portion stays alive to perform passive monitoring. As a result, there are no new emergency procedures to master.

I recently performed multiple, quick-succession starts on a Rolls-Royce Model 250-C28 in a Bell LongRanger II equipped with Honeywell’s Intellistart Plus+ system.

Although I never had a hot start in my several thousand hours in turbine helicopters, Intellistart Plus+ convinced me that I had few optimum starts. I did five starts, four of them with the rotors still turning from the previous shutdown.

On all five starts, the TOT climbed quickly to a preprogrammed 783°C (10°C below the 793° mark that begins a 10-second limit) and stabilized right there, plus or minus 2°C, for the duration of the start cycle. The procedure did not require throttle modulation.

On some of the starts, just after ignition at 14% of N1 (or a little higher, if needed to get the residual TOT down to 150°C, according to the flight manual), I immediately rolled the throttle to the flight idle detent using the same technique for starting a JetRanger equipped with the -C20B engine.

Instead of hot starting, the system consistently performed 17-second starts with the TOT pegged at 783°C—far better for the engine than I could ever do with manual modulation.

Try it yourself. The next time you start, see how long the start is and whether the TOT is stabilized or jumps all over the gauge as the mechanical fuel control schedules the fuel into the engine. Older fuel controls do not have any TOT information for their fuel scheduling decisions.

With Intellistart Plus+ or FADEC, a hot start should be a thing of the past. You can still do it if you don’t follow the simple procedures, but it is almost foolproof.

Another benefit of most standard FADECs and Intellistart Plus+ is that they can produce an accurate accounting of flights, starts, torque events, exceedences, and power checks.

[rotormandan]

I've flown 4 specific jetrangers. 2 at 1 company, 2 at another with about 800 hours total jetranger time.

 

1 company had a b2 ceco and a b3 bendex. The other company had a b2 bendex and a b3 ceco.

 

The cecos were definately modulated. If you rolled to idle at 15% it would hot start, no question. With both, at 15% you'd crack the throttle and after the initial tot spike, slowly roll on to keep temp in yellow. If the initial crack was to fast you could reduce throttle and it would slow or stop the needle. In an l3/l4 if you reduce throttle it's usually going to flame out.

 

With the bendex it didn't matter what you did at 15%. If you barrly cracked the throttle, rolled to or even past idle, it'd start the same.

 

When I got to the gulf, everyone said there were no modulated starts for jetrangers. I don't know why. During initial traing another pilot and I had to explain to the instructor that that was untrue. This was only a few years ago and we didn't have any jetrangers anymore (phi). But throughout my years at phi I heard the same thing all the time from different pilots. While modulated b models may be rare, they're out there. Maybe the gulf companies didn't use them.

 

The l3/l4 modulated seems way slower to me then the b2/b3. A slower temp spike and you can't roll back at all, though usually you don't need to.

[eagle5]

I flew a b3 with the Bendix. Piece of cake to start, especially for my first intro into turbines. Why did they change with the long ranger?

[Gomer Pylot]

The B models you had with CECO fuel controls that started too hot when the throttle was moved to idle were set up incorrectly. Too many mechanics really have no idea how the fuel control/governor system works, and too many pilots are willing to live with improperly adjusted controls, or don't have enough experience to know any different.

Edited June 29, 2014 by Gomer Pylot

[rotormandan]

It's not a setting. The procedure just isn't roll to idle with those. They were modulated starts. What would happen if you rolled an L model to idle instead of cracking the throttle? It'd do a whole lot more then start too hot. It'd go through the roof. Same with these.

 

I'm not the most experienced, or the most knowledgable, but the couple old guys that taught me in those ships are closing in on their 70's. They've only flown bell 47's and 206's in their whole ag career. One guy usually teaches most mechanics how to work on thoses things. I know they understand those 206's abd would've had the adjustment fixed at some point over the years.

 

I understand that these arrn't common but these were modulated starts. Not just ship that started warm.

[arotrhd]

Just to put some perspective for the comments, here's the straight poop from the RFM for whatever it's worth.

 

 

-WATCH FOR THE PATTERNS, WATCH FOR THE WIRES-

[aeroscout]

Interesting thread. I had no idea it would generate so many interesting and informative replies.

[Gomer Pylot]

I'm closing in on my 70s too. It has been a number of years since I flew a B with a CECO fuel control in it, but IIRC the flight manual starting procedure, and the procedure that was taught, was identical with either fuel control. If someone wants to modify the published procedures, that's up to them, and they have to be willing to accept the consequences.

[Nearly Retired]

Rotormandan, I started flying 206's in the late 1970s. We had both CECO's and Bendix's. You never knew which FCU a particular ship had. And it didn't matter, really. We started them exactly the same way: get to 15% and roll the throttle to idle. If it went hot then it was set incorrectly. The advantage of the CECO was that *IF* it went hot (weak battery, really cold OAT) you could squeak it back a bit and bring the TOT under control. But modulated starts like an L-1? No way.

 

Same when I went to PHI in 1987 - we still had some CECO's in the fleet.

 

Again, I'm with Gomer.

[iChris]

I'm closing in on my 70s too. It has been a number of years since I flew a B with a CECO fuel control in it, but IIRC the flight manual starting procedure, and the procedure that was taught, was identical with either fuel control. If someone wants to modify the published procedures, that's up to them, and they have to be willing to accept the consequences.

 

 

Rotormandan, I started flying 206's in the late 1970s. We had both CECO's and Bendix's. You never knew which FCU a particular ship had. And it didn't matter, really. We started them exactly the same way: get to 15% and roll the throttle to idle. If it went hot then it was set incorrectly. The advantage of the CECO was that *IF* it went hot (weak battery, really cold OAT) you could squeak it back a bit and bring the TOT under control. But modulated starts like an L-1? No way.

 

Same when I went to PHI in 1987 - we still had some CECO's in the fleet.

 

Again, I'm with Gomer.

 

Gomer Pylot and Nearly Retired are correct with their information. If the fuel control was set correctly and you’ve got a good battery, the CECO was as good as the Bendix.

 

Don’t confuse the starting procedures for the Bell 206 with a CECO/Bendix fuel control and 250-C18/C20 engine with that of the Bell 206L with a 250-C28/C30 engine.

 

The 250-C18/C20 uses combination axial/centrifugal stage compression.

 

The 250-C28/C30 uses single stage centrifugal compression (no axial stages).

 

Again, Don’t equate the same starting procedures to completely different engines.

 

To many have overcomplicated this “modulated” start with a CECO fuel control in the Bell 206B, it’s not complex. If the CECO fuel control was set correctly little if any modulation was required.

 

Don’t forget, this so called term “modulated start” is how you’ve been starting those old AS-350s up through the AS-350B2 all these years.

 

Modulate - To exert a modifying or controlling influence; regulate, adjust, set, modify, moderate

 

Edited June 30, 2014 by iChris

[aeroscout]

To me non modulated boils down to a simple step...rolling the throttle directly to the idle stop after achieving nominal N1.

[iChris]

(Click Photo to enlarge)

Edited July 3, 2014 by iChris

[rotormandan]

I guess I'm having a hard time with this. I can't find anything that written up about cecos. It seems common knowledge in the world of the internet that cecos are modulated but that doesn't mean it is correct. All I know is that the 2 ceco systems I've used definately had to be modulated. If the systems needed adjustments, then maybe the old guys were ok with that. As far as my experience goes, there's a big difference between the bendix and ceco and that's what I know.

[aeroscout]

I guess I'm having a hard time with this. I can't find anything that written up about cecos. It seems common knowledge in the world of the internet that cecos are modulated but that doesn't mean it is correct. All I know is that the 2 ceco systems I've used definately had to be modulated. If the systems needed adjustments, then maybe the old guys were ok with that. As far as my experience goes, there's a big difference between the bendix and ceco and that's what I know.

Just to specify, the LR has a standard fuel control that requires a modulated start, and an option for a non modulated start fuel control call the intellistart. The bendix/ceco don't apply to the LRs.

[Nearly Retired]

Well Dan, as far as the RFM is concerned, there shouldn't be any difference to the pilot. And I went back to the 206A RFM to see if Bell put a note in there about it.

 

They didn't.

 

I'd say...and I'm guessing here...that the outfit you worked for probably had the CECO's set up incorrectly for some reason...personal preference perhaps? In my experience, the CECO and Bendix were interchangeable as far as how the ship started. The fact that the CECO offers a small amount of adjustability on the TOT during the start doesn't mean you should have to avail yourself of it every time.

 

Then again...I've known pilots who SWEAR that they can "modulate" a Bendix in a B-model. And I'm here to tell you, after tens of thousands of starts of Bendix-equipped C-20B's over the years...*IF* there is any modulation of the TOT available to the pilot, it is TINY...and probably very FCU-specific...and probably illusory. They THINK they're affecting the TOT but they're probably not. I've tried and tried to squeak the throttle back in the various ships I've flown (206B's and Bo-105's), and all I ever get is cut-off.

[iChris]

I guess I'm having a hard time with this. I can't find anything that written up about cecos.

 

It seems common knowledge in the world of the internet that cecos are modulated but that doesn't mean it is correct.

 

All I know is that the 2 ceco systems I've used definately had to be modulated. If the systems needed adjustments, then maybe the old guys were ok with that. As far as my experience goes, there's a big difference between the bendix and ceco and that's what I know.

 

It's already documented in the Rolls Royce 250-C20 Operation & Maintenance Manual. The CECO was designed to start without any modulation, if adjusted correctly. It was also designed to allow, unlike the Bendix FCU, a modulated start. Below are excerpts from the Rolls Royce manual.

 

Set it up correctly and it will start without modulation. Note those two adjustments on the CECO "Start Derichment" & "Light-off Adjust"

 

Click photo to enlarge

 

 

Well Dan, as far as the RFM is concerned, there shouldn't be any difference to the pilot. And I went back to the 206A RFM to see if Bell put a note in there about it.

 

They didn't.

 

I'd say...and I'm guessing here...that the outfit you worked for probably had the CECO's set up incorrectly for some reason...personal preference perhaps? In my experience, the CECO and Bendix were interchangeable as far as how the ship started. The fact that the CECO offers a small amount of adjustability on the TOT during the start doesn't mean you should have to avail yourself of it every time.

 

Then again...I've known pilots who SWEAR that they can "modulate" a Bendix in a B-model. And I'm here to tell you, after tens of thousands of starts of Bendix-equipped C-20B's over the years...*IF* there is any modulation of the TOT available to the pilot, it is TINY...and probably very FCU-specific...and probably illusory. They THINK they're affecting the TOT but they're probably not. I've tried and tried to squeak the throttle back in the various ships I've flown (206B's and Bo-105's), and all I ever get is cut-off.

 

That's correct...

 

 

Rolls Royce 250-C20 Operation & Maintenance Manual (72-00-00 pg. 62)

 

The 250–C20 Series engines each have two qualified control systems; they are:

 

(1) CECO.

The MC–40 (250–C20, –C20B, –C20J) control system manufactured by the Chandler Evans Control Systems Division of Coltec Industries.

 

(2) Bendix.

The DP–N1 (250–C20) or DP–N2 (250–C20, –C20B, –C20F, –C20J), (control)/AL–AA1 (governor) control system manufactured by the Bendix Engine Controls Division of Allied Signal.

 

C. Starting Modes.

Starting procedures are given for an automatic start mode (CECO or Bendix system) and for a modulated start mode (CECO system only).

 

Automatic Start Mode:

The throttle is advanced directly to the IDLE detent when desired N1 cranking speed is reached.

 

Modulated Start Mode:

The throttle is advanced toward the IDLE detent in increments as required to increase TOT and N1 speed at a steady rate that remains within specified limits.

 

 

 

Rolls Royce 250-C20 Operation & Maintenance Manual (73-20-04 pg. 207)

 

F. Lightoff Adjustment

 

Make the lightoff adjustment by trimming the screw with a 5/64 in. Allen wrench to obtain engine starting fuel and exhaust gas temperature requirements. Turn the screw clockwise to decrease lightoff fuel flow.

 

G. Start Derichment Adjustment

 

The start derichment adjustment can be used to modify the starting fuel flow to improve cold weather starts, stagnated starts, or high altitude starts. Make the adjustment using a 1/4–in. Allen wrench having a 1/2 in. (13 mm) offset (or CECO wrench STD 67181). Turn clockwise (when viewed from end of adjustment screw) to enrich fuel flow for faster and hotter starts. Turn counter–clockwise for leaner fuel flow when starts are too hot. The normal setting is with the travel limiting screw at bottom center. Check the starting peak TOT after each setting until satisfactory starts are made.

Edited July 1, 2014 by iChris

[supergokougt]

Wow....Thanks for all the info back and forth. I got to watch and have a few starts explained. Should be starting it myself the next couple days.

[iChris]

Wow....Thanks for all the info back and forth. I got to watch and have a few starts explained. Should be starting it myself the next couple days.

 

Though we’re talking about a different engine and fuel control unit from that of the Bell 206B, the Bell 206L has also been troublesome to many during the modulation sequence.

 

Rich (hot) starts have been a problem. Causes like weak battery, delayed ignition or premature opening of the throttle are common. However, hot starts due to high fuel flow are normally caused by the fuel control. When you have an over-sensitive and hard to start Bell 206L (250-C30 engine) it could be a fuel control issue. Therefore, we’re back to maintenance and adjustment or even replacement of the fuel control.

 

Some companies have made it a culture of living with marginal aircraft maintenance, if it’s not completely dead, it’s good to go. Or terms like, we’ve been fly it like that for years and no one has a problem with it.

 

When the fuel control is suspected, ask maintenance to make the adjustments. Note the heading in the table below, “Adjustments to Improve Stating”

 

[Gomer Pylot]

Some mechanics are more knowledgeable than others, and some are more receptive to making adjustments than others. But pilots are the ones who have to make the starts, and shouldn't put up with maladjusted fuel controls. If it tries to melt every time you start it, then you need to force maintenance to do their job and adjust it properly. At least two adjustments will probably be needed each year, to compensate for different ambient temps, winter and summer. Depending on the location, you can probably get by without adjustments if you're willing to live on the edge, but you shouldn't have to. If the fuel control is adjusted properly, a start is a routine event. But if not, it can get far more exciting than necessary. I prefer boredom to terror.

[Nearly Retired]

...said the guy who flies helicopters for a living :-/

[Guest pokey]

I really hate to say this, and I know it is a cheep shot, (but I have been the victim also of them by him)

 

if it doesn't start the 1st time? there must be a bug in the system

[aeroscout]

I really hate to say this, and I know it is a cheep shot, (but I have been the victim also of them by him)

 

if it doesn't start the 1st time? there must be a bug in the system

It's a lighthearted friendly jest, at the worst. That won't keep someone from blowing it up into the unimaginable.

[PanzerKop1973]

Hello everybody!

Could any pilot in this forum provide me a Bell 206 Long Ranger checklist file or indicate where could I find one to download it please?

Thanks in advance from Santiago de Chile.

arayaparodi@hotmail.com