Bell 206: JetRanger and LongRanger
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20 years ago I had an oil line from gearbox to compressor support hub break just forward of the B-nut at the gearbox end. This was a C18 engine and was found to be a high freq from the engine itself. Engine was removed for overhaul.
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Agree with mfriskel, check your engine for vibes. Also the T/R and main driveshafts if the eng vibe level is OK. It could be something as simple as a start/gen vibration. Good luck.
(EDIT)
(EDIT)
Last edited by sprocket; 6th Apr 2005 at 09:34.
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It's a bit long ago now for me to remember the details accurately but isn't there an air pipe that gets disconnected every time you do a comp wash in order to prevent water getting into it?
I have half a recollection of having to very carefully check that (a) it had been done up again and (b) it hadn't cracked with repeated daily on/off handling.
Please excuse if this isn't relevant.
Cheers
JerryG
I have half a recollection of having to very carefully check that (a) it had been done up again and (b) it hadn't cracked with repeated daily on/off handling.
Please excuse if this isn't relevant.
Cheers
JerryG
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If this is the P3 line in the Allison, it has been the cause of a number of engine failures over the years.
There appear to be a number of causes for the failure - two predominant ones are fatigue and maintenance error. The first is self explanatory; the second (and of course the first) can be caused by the frequent connection/disconnection cycles. As JerryC has mentioned, in the absence of an installed valve for the purpose, it is disconnected and blanked for every comp wash. There is an STC for the valve but it is not an 'approved' modification is some States (UK).
Some oil companies/operators replace the P3 valve at regular intervals - this appears to solve the problem.
There appear to be a number of causes for the failure - two predominant ones are fatigue and maintenance error. The first is self explanatory; the second (and of course the first) can be caused by the frequent connection/disconnection cycles. As JerryC has mentioned, in the absence of an installed valve for the purpose, it is disconnected and blanked for every comp wash. There is an STC for the valve but it is not an 'approved' modification is some States (UK).
Some oil companies/operators replace the P3 valve at regular intervals - this appears to solve the problem.
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The Pc (P3) line from the compressor scroll to the Pc filter does not appear to be the one mugsy has mentioned.
mugsy wrote:
Although the Pc line has been a problem over the years.
Vfr: The Chadwick test is a vibration analysis check. Chadwick is one brand name of the test equipment that is commonly used and is also used a lot for rotor track/balancing.
mugsy wrote:
The cause appears to be a cracked air line between the governor and Fuel control unit
Vfr: The Chadwick test is a vibration analysis check. Chadwick is one brand name of the test equipment that is commonly used and is also used a lot for rotor track/balancing.
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On June 27 a Scweizer 269D made a hard landing after an engine failure. The Investigation reveiled a broken Pc line (compressor discharge pressure senseline to fuel control). Problem was probably too much tension on the line due to the fact that it misaligned. Misalignment of this line is not uncommon, but enough misalignment in conjunction with excessive vibration could result in a broken line. Rolls Royce has issued CSL A-1166 which advises to install the line without tension due to misalignment. Some extensive bending could be required!
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Long Ranger L3 crash
Saw the same thing about 10 yrs ago while working for the (probably!) same utility company. If I remember rightly the eventual cause was routing/ clamping of the P3 line, which caused it to be IN TENSION all the time. It may also have been a (slightly) wrong part no, of subtly different length. ( was a long time ago!) With the natural hi-freq vibe of the engine/ MRGB, the line was vibrating which caused either chafing at a P-clamp and/or fatigue fracture, on a bend possibly.
Hope this helps Mugsy. Long time no see. Man those Line Audits were fun! (?)
Hope this helps Mugsy. Long time no see. Man those Line Audits were fun! (?)
VFR: It's the old way of checking whether the rotating blades (TR and MR) are in sync (tracked) and balanced. Very hit and miss affair, takes bloody hours.
New gen a/c have digital analysis plug in diagnostic kits, much more accurate and very quick (in the right hands).
New gen a/c have digital analysis plug in diagnostic kits, much more accurate and very quick (in the right hands).
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Hey VFR I'm not sure what side of bed Thomas Coupling woke up on cos he does not like Chadwick but his answer is wrong.
Chadwick is the name of the system designed by Mr Chadwick (of all people) from California to balance any rotating system. It is a digital analays system and is used throughout the world on blades turbines shafts etc etc.
On a helicopter the time comes in setting up sensors on the frame, main blades, TR blades, tail boom etc. Then you simply fly the helicopter in the regimes of normal operation, the computer does the rest and tell you where to place balance weights.
You land put the weights on where needed and voila.....a smooth chopper.
Other sysems such as strobe or bamboo and paint also work well!!!!!!!!
Chadwick is the name of the system designed by Mr Chadwick (of all people) from California to balance any rotating system. It is a digital analays system and is used throughout the world on blades turbines shafts etc etc.
On a helicopter the time comes in setting up sensors on the frame, main blades, TR blades, tail boom etc. Then you simply fly the helicopter in the regimes of normal operation, the computer does the rest and tell you where to place balance weights.
You land put the weights on where needed and voila.....a smooth chopper.
Other sysems such as strobe or bamboo and paint also work well!!!!!!!!
Join Date: Mar 2005
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Longranger crash, South Africa
Thanks for the input, folks.
Subsequently found out that a Jetranger went down in RSA with the same problem. That makes 4 in this neck of the woods.
Seems to me that if the tightening of a nut can stress the flange, or that a slight misalighnment of a pipe can keep it in stress, then you can bet that we'll have more failures.
That sound like poor design to me.
Incidentally someone in the industry sugested that when we tried to find high Fx resonance with a Chadwick we were unlikely to find a problem because it is not designed to pick up a turbine bearing going pear-shaped. It is better at medium frequencies such as props, rotors, drive-shafts. He sugested something called " microvib" (I think that's the spelling) Any comments?
Subsequently found out that a Jetranger went down in RSA with the same problem. That makes 4 in this neck of the woods.
Seems to me that if the tightening of a nut can stress the flange, or that a slight misalighnment of a pipe can keep it in stress, then you can bet that we'll have more failures.
That sound like poor design to me.
Incidentally someone in the industry sugested that when we tried to find high Fx resonance with a Chadwick we were unlikely to find a problem because it is not designed to pick up a turbine bearing going pear-shaped. It is better at medium frequencies such as props, rotors, drive-shafts. He sugested something called " microvib" (I think that's the spelling) Any comments?
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Occurrences with aircraft powered by an Allison 250 engine in which Pc line fatigue was a causal factor:
13-09-1984 Denver USA Bell 206L-3
05-10-1985 Islamorada USA Bell 206L
30-03-1989 Vallejo USA Hughes 369D
08-12-1989 Waimea USA Hughes 369 HS
21-04-1990 Williamsport USA Bell 206 B3
09-09-1990 Kokhanok USA Bell 206 B
11-07-1996 Pigeon Forge USA Bell 206 B
27-06-1998 Assen Netherlands Schweizer 269D
13-04-2000 El Paso USA Hughes OH-6A
21-08-2000 Dartford Marshes UK Hughes 369E
I wonder how many others there are besides these and how long is this problem going to continue before anything is done about this?
13-09-1984 Denver USA Bell 206L-3
05-10-1985 Islamorada USA Bell 206L
30-03-1989 Vallejo USA Hughes 369D
08-12-1989 Waimea USA Hughes 369 HS
21-04-1990 Williamsport USA Bell 206 B3
09-09-1990 Kokhanok USA Bell 206 B
11-07-1996 Pigeon Forge USA Bell 206 B
27-06-1998 Assen Netherlands Schweizer 269D
13-04-2000 El Paso USA Hughes OH-6A
21-08-2000 Dartford Marshes UK Hughes 369E
I wonder how many others there are besides these and how long is this problem going to continue before anything is done about this?
Last edited by Alfa Hotel; 8th Apr 2005 at 04:28.
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b206 extension pedals
can anyone tell me where i would get extension pedals for a jetranger, i know paravon do them in the states .is there anyone in europe who supplies them.also same again for the md 500
cs
cs
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Maybe you should look into purchasing a pair of “extension legs”.
No TSO required.
No W & B calculation required.
Probably cheaper??
And the girls might begin to notice you at the aero club Bar.
No TSO required.
No W & B calculation required.
Probably cheaper??
And the girls might begin to notice you at the aero club Bar.
Join Date: Sep 2003
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Gymbal stop!
C'mon, that comment was a bit below the knees!
Chopper squad, i know im a bit vertically challenged but those pedal adjustments come back a fair way, are you really that short!!...can you see over the top of the panel at least
C'mon, that comment was a bit below the knees!
Chopper squad, i know im a bit vertically challenged but those pedal adjustments come back a fair way, are you really that short!!...can you see over the top of the panel at least
Join Date: Jan 2005
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they keep calling me a bum .now i know why.thanks guys
your the best.
by the way its for longer not shorter.i no you ausi jocks
think shorter ,so the girls say..........................
cs
your the best.
by the way its for longer not shorter.i no you ausi jocks
think shorter ,so the girls say..........................
cs
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Conflicting info on B206 M/R blades???
Can you mix and match M/R blades for a B206?
Part numbers are:
206-010-200-033 (single tab) and 206-010-200-133 (twin tab)
Some say you can others say not?
As far as I know the only difference is is single tab vs. duel tab.
Thanks in advance...
Ps- If you can, is their any negative aspect to doing so?
Part numbers are:
206-010-200-033 (single tab) and 206-010-200-133 (twin tab)
Some say you can others say not?
As far as I know the only difference is is single tab vs. duel tab.
Thanks in advance...
Ps- If you can, is their any negative aspect to doing so?
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You can definitely as I have been flying a B206 BIII for a long time time with a mixed set.
Rightly mentioned that the static balance is bit tricky but patience does it.
We have found that during blade tracking in flight always do the setting on the blade with the twin tabs first and then "fine tune" from there.
Rightly mentioned that the static balance is bit tricky but patience does it.
We have found that during blade tracking in flight always do the setting on the blade with the twin tabs first and then "fine tune" from there.