Bell 206: JetRanger and LongRanger
Join Date: Oct 1998
Location: Back in the Black Country
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I am working in the Middle East, and the local authority are loath to give any approvals unless it can be clearlty demonstrated that annother competant authority has already approved whatever it is your planning to do (ie an STC) therefore I am stuck!
Thanks
Thanks
JetRanger drivetrain question
I own a 206 A/B with a C20 engine. She's an old girl but flies well
I'm going thru the painful process of 'overhauling' my transmission and M/R head. My old trans was the -015 3 stage sort, so I've sourced a -029 (BIII) unit to replace it. (Anybody need a -015 trans with 25 hours left on it??).
Took a risk on overhauling my own head (a -021 'small' unit): bad mistake! Yoke and grips both shot as well as timex pins fittings etc. I reckon parts alone are c$22k. As I understand it, if I fit them all, I'll get 2,500 hours TBO and still have good life left on the trunnion and grips, so nothing to worry about for a while.
I've also found a -127 (BIII) head with around 2,200 hoursTBO for $26k: one benefit of this unit is that it's bolt on.
So, I've got three choices:
1) buy the -127 and sell the good bits out of my old head, and swallow the labour so far as 'experience'
2) buy the -127 head and continue to overhaul mine and sell it on
3) carry on with the overhaul on my head and stop thinking about the -127!
Any advice?
Question is: does having a 'BIII' drivetrain give me any other advantages for when I come to sell the machine, or upgrade it? Eg, could I fit a c20B at some point when I've put more money in the piggy bank?
I'm going thru the painful process of 'overhauling' my transmission and M/R head. My old trans was the -015 3 stage sort, so I've sourced a -029 (BIII) unit to replace it. (Anybody need a -015 trans with 25 hours left on it??).
Took a risk on overhauling my own head (a -021 'small' unit): bad mistake! Yoke and grips both shot as well as timex pins fittings etc. I reckon parts alone are c$22k. As I understand it, if I fit them all, I'll get 2,500 hours TBO and still have good life left on the trunnion and grips, so nothing to worry about for a while.
I've also found a -127 (BIII) head with around 2,200 hoursTBO for $26k: one benefit of this unit is that it's bolt on.
So, I've got three choices:
1) buy the -127 and sell the good bits out of my old head, and swallow the labour so far as 'experience'
2) buy the -127 head and continue to overhaul mine and sell it on
3) carry on with the overhaul on my head and stop thinking about the -127!
Any advice?
Question is: does having a 'BIII' drivetrain give me any other advantages for when I come to sell the machine, or upgrade it? Eg, could I fit a c20B at some point when I've put more money in the piggy bank?
Join Date: Jul 2000
Location: The Daylight Saving Free Zone
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Have you considered what the throwaway life remaining is of the existing components in the B3 head as opposed to just the O/H life? There could be more expensive parts due for replacement because of life expiry at the next O/H too. You do the sums.
If the T/M and head are the only B3 components that you have in the drivetrain and you still want to achieve full B3 status then you would still have to upgrade the ….
FWU
Cooler blower
T/R driveshaft
T/R gearbox
Tailrotor assy
Some rear fuselage stiffening and associated downtime.
There is a BHT service instruction that gives you all the details but I cant remember its number.
If the T/M and head are the only B3 components that you have in the drivetrain and you still want to achieve full B3 status then you would still have to upgrade the ….
FWU
Cooler blower
T/R driveshaft
T/R gearbox
Tailrotor assy
Some rear fuselage stiffening and associated downtime.
There is a BHT service instruction that gives you all the details but I cant remember its number.
Join Date: Sep 2003
Location: Australia
Age: 47
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206 Tt Straps
Ive just ordered a set off straps for our 206, no problem however, can anyone care to comment on bell ever cancelling the A.D is it really neccesary for the replacement on the due time reqirement, or is bell having too much success with the ongoing sale of tt straps.
curious???
curious???
Join Date: Jan 2003
Location: TI
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Are you replacing them on flight time or calendar time? In days past you used to get a credit for the calendar life remaining. Try flying with either or both failed and get back to us!!
Join Date: Sep 2003
Location: Australia
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We recently purcahsed the 206 from overseas and they only have 300 hrs flown off them, calendar life is up but the previous owners didnt use the machine a great deal, since weve owned it about 3 months weve put 100 odd hous on it. bell said today they will give a rebate of 15% with straps that have over 600 hrs remaining.
Join Date: Jun 2003
Location: Australia
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Belly Tank
TT straps have hourly and time limits imposed on them because they are a flight critical component. If your straps go you go too!!
They had the life limit put on them due to quite a few failures early on in the JR's life.
Straps are constructed of many thousands of windings of stainless steel wire these windings covered in a plastic coating.
These windings are susceptible to fatigue that is why there is an hour limit, they are also susceptible to corrosion believe it or not that is why they have a calendar life.
If you want any more information talk to the guy that put your red machine on the register he is quite knowledgable.
Some military Bells dont have a life limit on the straps but thats just the military way.... just another number.
TT straps have hourly and time limits imposed on them because they are a flight critical component. If your straps go you go too!!
They had the life limit put on them due to quite a few failures early on in the JR's life.
Straps are constructed of many thousands of windings of stainless steel wire these windings covered in a plastic coating.
These windings are susceptible to fatigue that is why there is an hour limit, they are also susceptible to corrosion believe it or not that is why they have a calendar life.
If you want any more information talk to the guy that put your red machine on the register he is quite knowledgable.
Some military Bells dont have a life limit on the straps but thats just the military way.... just another number.
Join Date: Dec 2002
Location: World Wide
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...If your TT straps have exceeded thier calender life ....change them ASAP ... or we might be reading about you in the "crash comics".
The straps are very robust BUT are subject to internal corrossion (?????) and if they fail its all over mate.
Due to their being sealed up in an epoxy type covering theyare not able to be visually inspected they are NOT an "on condition" item.
The straps are very similar to those used in the Bo105 Bk117 series of a/c and I think the only head failure (??) ever recorded on the Bo105 was from a TT strap failure !!!!
The straps are very robust BUT are subject to internal corrossion (?????) and if they fail its all over mate.
Due to their being sealed up in an epoxy type covering theyare not able to be visually inspected they are NOT an "on condition" item.
The straps are very similar to those used in the Bo105 Bk117 series of a/c and I think the only head failure (??) ever recorded on the Bo105 was from a TT strap failure !!!!
Join Date: Sep 2003
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SPINNING WINGS
...If your TT straps have exceeded thier calender life ....change them ASAP ... or we might be reading about you in the "crash comics".
I look after our machines impecably, and i certainly dont fly with components out of date or hours i was mearly asking a question
...If your TT straps have exceeded thier calender life ....change them ASAP ... or we might be reading about you in the "crash comics".
I look after our machines impecably, and i certainly dont fly with components out of date or hours i was mearly asking a question
Join Date: Jul 2001
Location: Florida
Age: 52
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B206 Boost Pumps.
Ok here's the situation:
We are at 9000 MSL in a Jet Ranger, crossing some mountains and giving sufficient ground clearance over some condor sanctuaries.
We notice that the fuel pressure has dropped to just above the red line. We then descend to around 6500 MSL and the pressure goes back to the middle of the green. Just out of interest we start to climb again and sure enough the pressure starts to drop again. There are no fuel pump lights illuminated and on landing we check both pumps and they are working fine.
Has anyone else experienced this? Is it normal?
I'm still waiting for a reply from Bell, but any answers / ideas / suggestions would be appreciated.
We are at 9000 MSL in a Jet Ranger, crossing some mountains and giving sufficient ground clearance over some condor sanctuaries.
We notice that the fuel pressure has dropped to just above the red line. We then descend to around 6500 MSL and the pressure goes back to the middle of the green. Just out of interest we start to climb again and sure enough the pressure starts to drop again. There are no fuel pump lights illuminated and on landing we check both pumps and they are working fine.
Has anyone else experienced this? Is it normal?
I'm still waiting for a reply from Bell, but any answers / ideas / suggestions would be appreciated.
Join Date: Jan 2003
Location: TI
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The Jet Fuel Barometer?
Like the mercury in Torricelli's barometer the column of fuel from the tank to the engine will appear heavier at a lower barometric pressure. Sea level standard baro 760 millimetres, 9000' its about 543 millimetres, a difference of about 220 mm or 4.4 psia which is probably the difference you are looking at.
Hence the instruction in the FM ref "Operations with one boost pump inop above 5000'" or somesuch.
Makes sense to me.........
Hence the instruction in the FM ref "Operations with one boost pump inop above 5000'" or somesuch.
Makes sense to me.........
Join Date: Mar 2004
Location: Parker, Colorado
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I think that is NOT normal. It sounds to me like you have a slight leak in one of your boost pumps somewhere, or a weak boost pump. I'd check all the boost pump lines, and look under the rear floor around the fuel tank, ejectors, etc. And I'd definitely pursue Bell to find an answer. It doesn't sound like it could be your main fuel pump, because it doesn't produce enough pressure above 6,000' to keep it above the redline.
When you do your boost pump checks, does one seem stronger than the other? Can you find a place to land at 9000' and perform a boost pump check to see if one of your pumps allows the fuel pressure to fall below redline? My guess is that one of your pumps is doing most of the work, or you have a slight air leak somewhere.
When you do your boost pump checks, does one seem stronger than the other? Can you find a place to land at 9000' and perform a boost pump check to see if one of your pumps allows the fuel pressure to fall below redline? My guess is that one of your pumps is doing most of the work, or you have a slight air leak somewhere.
Well, for starters the main fuel pump (engine-driven) doesn't produce pressure (except into the FCU), it sucks. The pressure gauge measures only the electric boost pumps, and as GCN says, the higher you go, the less assistance they have from air pressure.
With both pumps out, the engine-driven pump cannot suck the fuel if you are above (geeze, what were the numbers??) 5300'?? The problem produces its own solution, because the helo rapidly descends back below that height, all you have to do is restart the engine and hope the ground is somewhat lower than that.
An "air leak" ? A fuel leak to cause a loss of pressure will spray fuel everywhere. An air leak happens in things like a 76 where there are no pressure pumps, just suction, and it is safer to have air come into a line than to have fuel come out of it.
With both pumps out, the engine-driven pump cannot suck the fuel if you are above (geeze, what were the numbers??) 5300'?? The problem produces its own solution, because the helo rapidly descends back below that height, all you have to do is restart the engine and hope the ground is somewhat lower than that.
An "air leak" ? A fuel leak to cause a loss of pressure will spray fuel everywhere. An air leak happens in things like a 76 where there are no pressure pumps, just suction, and it is safer to have air come into a line than to have fuel come out of it.
Join Date: Jan 2003
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Granted one of the boost pumps may be weak but you would have checked that in the pre takeoff checks hopefully. As the pressure gauge only measures the pressure of the "best" pump, pop each breaker one at a time and see what the pressure is. mikeferg this is a ShortRanger so there are no ejectors or lines running along the floor! We won't talk about the L that's a can of worms on its own.
I think the 250C20 is OK with a pressure at the main pump inlet of 0". The airframe manufacturer probably recommends otherwise though.
AC, Air leaks are just as bad as fuel leaks, flameout for one and a fire hazard for the other, take your pick. Bendix equipment is fairly tolerant and will pass dirt, water, nuts and bolts, some bubbles, but not the gear that used to be around made by CECO!
Vaquero,
Of course you will post Bell's response won't you.
I think the 250C20 is OK with a pressure at the main pump inlet of 0". The airframe manufacturer probably recommends otherwise though.
AC, Air leaks are just as bad as fuel leaks, flameout for one and a fire hazard for the other, take your pick. Bendix equipment is fairly tolerant and will pass dirt, water, nuts and bolts, some bubbles, but not the gear that used to be around made by CECO!
Vaquero,
Of course you will post Bell's response won't you.
Join Date: Jan 2001
Location: Chilliwack, BC Canada
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Sounds pretty much normal Ops from any 206 that I've flown, I have 10,000 on type, mostly at altitude.
There is a procedure outlined in the Maintenance Manual to check for air leaks in the fuel system ...basically run the aircraft on the ground at 100% Nr for 2 minutes with BOTH boost pumps OFF (and at a low fuel quantity), the Eng driven pump sucks, so without boost pressure, it Will find any air-leaks ! This test should be done after any In-Tank maintenance.
There is a procedure outlined in the Maintenance Manual to check for air leaks in the fuel system ...basically run the aircraft on the ground at 100% Nr for 2 minutes with BOTH boost pumps OFF (and at a low fuel quantity), the Eng driven pump sucks, so without boost pressure, it Will find any air-leaks ! This test should be done after any In-Tank maintenance.
Join Date: Jul 2000
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Sounds like a good time to check your fuel system, in case there is an underlying problem. (When was the last annual done?)
Another possibility is the check valves. There is one on each boost pump. The pumps need to be removed to clean the check valves but may be worth it in case there is contamination building up.
If one boost pump is producing a lower pressure than the other one when operated individually, then the check valve in the "better" pump could be the culprit. Also have the lines checked for leakage while the pumps are out.
Most capable mechanics/engineers should be able to figure the problem out fairly quickly.
Another possibility is the check valves. There is one on each boost pump. The pumps need to be removed to clean the check valves but may be worth it in case there is contamination building up.
If one boost pump is producing a lower pressure than the other one when operated individually, then the check valve in the "better" pump could be the culprit. Also have the lines checked for leakage while the pumps are out.
Most capable mechanics/engineers should be able to figure the problem out fairly quickly.
Might be worth getting engineering to back-blow( from the tank !) the vent line to ensure it`s clear of spiders /muck/moisture. I presume at 9000 ft you were not above a freezing level in CA?
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Without regard to the "limits" being approached, I still maintain that the change in pressure with altitude is "normal" as per 407Drivers comments.
407Drivers comments re testing of the system is definitely a requirement on ALL "L" models. Ever wondered why one Boost pump is hard wired in L1 thru 4?
407Drivers comments re testing of the system is definitely a requirement on ALL "L" models. Ever wondered why one Boost pump is hard wired in L1 thru 4?
Join Date: Jul 2001
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Thanks for all the replies.
I'm expecting a call from Bell today, so will post the reply. The first guy I spoke to over there suggested the change in pressure with altitude. However the question on that is that if we had gone higher, would it have dropped below the red line? If we were only at 9000 MSL and near the limit how do people get upto 14-15,000? The temperature up there was well above freezing. She's due for a 100 hour in about 35 hours.
I personally think there is more to it than air pressure change, but time will tell!
I'm expecting a call from Bell today, so will post the reply. The first guy I spoke to over there suggested the change in pressure with altitude. However the question on that is that if we had gone higher, would it have dropped below the red line? If we were only at 9000 MSL and near the limit how do people get upto 14-15,000? The temperature up there was well above freezing. She's due for a 100 hour in about 35 hours.
I personally think there is more to it than air pressure change, but time will tell!