Jump to content


TigerTugsFrasca VRForum468VOLO_VRHome200Helicopter Academy
Photo
- - - - -

Bell 206 85%TQ 82KT flight limitation exceeded


  • Please log in to reply
26 replies to this topic

#1 Whistlerpilot

Whistlerpilot

    VR Veteran Poster

  • VR Member
  • PipPipPipPipPipPipPip
  • 290 posts
  • Gender:Male
  • Location:BC
  • Interests:Skiing climbing mountain biking kayaking flying and having a long term relationship!
  • Company working for:A 5 ship company in a small BC mountain town

Posted 09 December 2017 - 01:49

Im working for a company flying H125 B3e overseas. However they have one Bell 206 which I rarely fly. However while doing a recurrent training flight for the pilot who flys the 206 all the time I discovered that the power checks were being done at 90% TQ 6000PA in level flight, which gives over 100KT airspeed. Needless to say this practice has immediately stopped. We looked in the maintenance manual but couldnt find an unscheduled inspection for this exceedance of the flight limitation. I have decided not to fly in this aircraft until I have a response from Bell tech rep that no maintenance action is required. This is a remote underdeveloped country so that may take some time.

My question is does anyone have experience with exceedance of this limitation? I was taught the limitation is because of mast bending at high TQ airspeed combinations.

Perhaps Ichris has some insight? I used to be a regular VR poster but now am just way to busy to get on here much and also dont like to get in online wars. I would really appreciate if someone has experience with this situation.

Thanks in advance,

Eric

When life's path is steep keep your mind even.


#2 WolftalonID

WolftalonID

    VR Veteran Poster

  • VR Member
  • PipPipPipPipPipPipPip
  • 582 posts
  • Gender:Male
  • Location:New Meadows, ID
  • Interests:Flying, helicopters, back country, archery elk hunting, wood working!
  • Company working for:Mildly experienced stick wiggler/rookie expert

Posted 09 December 2017 - 10:19

The company I work for is a Bell Certified service center for 429/407/206/505. Our head of maintenance might know this, due to the fact we are at a hign altitude all the time. Let me ask and see what he says.
Sometimes we think we know it all....only later to discover we only knew all we had learned. Never stop learning.

#3 Hand_Grenade_Pilot

Hand_Grenade_Pilot

    VR Veteran Poster

  • VR Member
  • PipPipPipPipPipPipPip
  • 154 posts
  • Gender:Male
  • Location:USA
  • Company working for:GoM

Posted 09 December 2017 - 13:01

The company I work for is a Bell Certified service center for 429/407/206/505. Our head of maintenance might know this, due to the fact we are at a hign altitude all the time. Let me ask and see what he says.

The limitation has nothing to do with altitude. What he is referring to is a limitation in the 206 RFM that basically prevents using takeoff TQ during cruise. Which is due to pedal position; in forward flight the pedals are near neutral. Which means almost all of the TQ produced is being applied to the main transmission and mast.

In a hover and at low speed, you have power pedal applied. A significant amount of the TQ produced is being applied to the tail section, which allows you to pull 100% TQ without damaging the mast.

Specifics aside though, would still like to hear what your DoM says.
  • Wally likes this
Aviation is a cruel mistress. When she's not taking your money, she's coming up with creative ways to kill you.

#4 Eric Hunt

Eric Hunt

    VR Veteran Poster

  • VR Member
  • PipPipPipPipPipPipPip
  • 831 posts
  • Gender:Male
  • Location:Near the beach

Posted 10 December 2017 - 02:57

Our understanding was that it was a mast bending problem, poke the stick too far forward with that much power and the mast has problems once the horizontal stabiliser gets some airspeed up and tries to pull the tail back down. Use any power you like up to 82kt, but go faster than that and you are back to Max cont cruise power 85% Tq.


  • 500F and AS350 pilot like this

#5 Whistlerpilot

Whistlerpilot

    VR Veteran Poster

  • VR Member
  • PipPipPipPipPipPipPip
  • 290 posts
  • Gender:Male
  • Location:BC
  • Interests:Skiing climbing mountain biking kayaking flying and having a long term relationship!
  • Company working for:A 5 ship company in a small BC mountain town

Posted 11 December 2017 - 00:23

Thats what I was also taught. However I still dont know the consequence for repeated exceedance of this flight limitation. The maintenance manual list unscheduled inspections for over torque, over temp, sudden stoppage, etc, but this limitation is so obvious and easy to avoid that they didnt consider it would be violated. So Im holding my ground and not flying the aircraft until Bell gives the thumbs up. I was just hoping someone might have encountered this before and have some facts from Bell. Im guessing Ichris has some insight but perhaps some of the old regulars on here dont hang around as much. Bob youve got more 206 time than most, have you heard of this flight limitation being repeatedly exceeded?

Will share what I learn. In the meantime Im flying home in a week after almost a year overseas and this outcome will effect if I ever fly this aircraft again. Third world problems, and I dislike green beer. Cant wait for a good Pacific Northwest microbrew!

Cheers, Eric

When life's path is steep keep your mind even.


#6 WolftalonID

WolftalonID

    VR Veteran Poster

  • VR Member
  • PipPipPipPipPipPipPip
  • 582 posts
  • Gender:Male
  • Location:New Meadows, ID
  • Interests:Flying, helicopters, back country, archery elk hunting, wood working!
  • Company working for:Mildly experienced stick wiggler/rookie expert

Posted 11 December 2017 - 13:16

Eric, the ship is fine.

Spoke with our DOM, he says talk to Bell for specifics but they probably wont have you do anything. Power checks are typically completed within that 5 min window of allowances. There is no inspection for mast bending unless you take it out and check.

Based on what you describe there was plenty of margin for what the pilot was doing, but moving forward the best specific way to do a power check is establish a 60kt climb at 100%, DO NOT go over, and take a picture send the photo to your DoM. (Picture should be of the gauges not of your finger or a selfie...to clarify haha).

But rest assured the ship is fine, carry on, relax a bit. ;)

He is a 27 year Bell certified tech with an A&P &IA certification.
Sometimes we think we know it all....only later to discover we only knew all we had learned. Never stop learning.

#7 Whistlerpilot

Whistlerpilot

    VR Veteran Poster

  • VR Member
  • PipPipPipPipPipPipPip
  • 290 posts
  • Gender:Male
  • Location:BC
  • Interests:Skiing climbing mountain biking kayaking flying and having a long term relationship!
  • Company working for:A 5 ship company in a small BC mountain town

Posted 11 December 2017 - 20:04

Thanks WolftalonID, of course these are tough machines and my gut feeling is theres no problem. My concern is the repeated occurrence. Im still not gonna fly it until the Bell tech rep says good to go. Mostly this is taking a stand on maintenance. Engineering should know better than to ask something that exceeds limitations and Pilot should know better than to do it if it exceeds a flight limitation. So Ive drawn the line in the sand on this one.

When life's path is steep keep your mind even.


#8 WolftalonID

WolftalonID

    VR Veteran Poster

  • VR Member
  • PipPipPipPipPipPipPip
  • 582 posts
  • Gender:Male
  • Location:New Meadows, ID
  • Interests:Flying, helicopters, back country, archery elk hunting, wood working!
  • Company working for:Mildly experienced stick wiggler/rookie expert

Posted 12 December 2017 - 12:41

Thats the point, there was no limitation exceeded. If there was, Bell would publish a Maintenance schedule to adhere to. Greg M with Bell might be your go to guy, he is ours, so ask him, but your answer is going to most likely be the same.
Sometimes we think we know it all....only later to discover we only knew all we had learned. Never stop learning.

#9 helonorth

helonorth

    VR Veteran Poster

  • VR Member
  • PipPipPipPipPipPipPip
  • 1,041 posts

Posted 12 December 2017 - 13:59

It needs to be inspected. There is no "5 minute window" for this. Contact Bell. Also, the power check can be performed in a hover. See the FM.



#10 Rotorhead84

Rotorhead84

    VR Veteran Poster

  • VR Member
  • PipPipPipPipPipPipPip
  • 148 posts
  • Gender:Male

Posted 17 December 2017 - 17:43

It needs to be inspected. There is no "5 minute window" for this. Contact Bell. Also, the power check can be performed in a hover. See the FM.

 

I only have 4 hours in a jetbuggy but 2,000hrs in 58s.  There is definitely a 5 minute limit on power over 85% tq in the 58.  Not sure why it would be any different in the jetbuggy.


  • WolftalonID likes this

#11 Mikemv

Mikemv

    VR Veteran Poster

  • VR Member
  • PipPipPipPipPipPipPip
  • 864 posts
  • Gender:Male
  • Location:Naples, Florida
  • Interests:Helicopter Aviation for the last 50+ yrs
  • Company working for:HelicopterSBT, Unmanned Safety Institute

Posted 17 December 2017 - 18:26

Guys,

 

All exceedances of limitations should be written up (documented) with quantity and duration "Every" time.

 

When there is no subsequent action listed in the MM for the exceedance, OEM Tech Reps either in the region or at the factory support center should be contacted for guidance.

 

This limitation is about mast bending in an area that was not tested during initial engineering calculations. The exceedance puts pressure on the mast, mast bearing and other transmission locations/components. I do not believe this limitation was listed in the early B206 models but grew to be an issue with time in service.

 

Factory information will tell us what they consider to be a grounding condition if one exist, possiibly something like "I flew at 110 kts. for 4 minutes at 95%Q or I flew at 89 kts. for 30 seconds at 87%Q which would both be exceedances but I suspect with different recommendations if any from the OEM. That said, if there was a list of 12 or 27 exceedances listed due to accepting this practice, I would not fly the aircraft and expect component changes to be recommended or required by the OEM.

 

No pilot should ever state that it is not a limitation exceedance because no immediate inspection requirements are required!


  • Wally and helonorth like this

#12 Mikemv

Mikemv

    VR Veteran Poster

  • VR Member
  • PipPipPipPipPipPipPip
  • 864 posts
  • Gender:Male
  • Location:Naples, Florida
  • Interests:Helicopter Aviation for the last 50+ yrs
  • Company working for:HelicopterSBT, Unmanned Safety Institute

Posted 17 December 2017 - 18:48

Thats the point, there was no limitation exceeded. If there was, Bell would publish a Maintenance schedule to adhere to. Greg M with Bell might be your go to guy, he is ours, so ask him, but your answer is going to most likely be the same.

WolftalonID,

 

Respectfully as an industry professional I know you do not adhere to not following industry SOPs and manufacturers requirements. Accepting the procedure of not writing up an exceedance leads to accepting other procedures that become standardized (accepted) in the company structure. I do not believe you would teach this as the company 135 chief instructor!

 

The USHST has addressed this as causal factors in accidents and is certainly not an industry SOP or Best Practice. When we have questions about maintenance that are not clearly defined, go to the OEM for guidance. Company DOMs are not qualified to make these determinations. There may be a NDT procedure recommended or other procedure for continued airworthiness post A/S - Q limitation exceedances?


  • helonorth and 500F like this

#13 SBuzzkill

SBuzzkill

    VR Veteran Poster

  • VR Member
  • PipPipPipPipPipPipPip
  • 1,812 posts
  • Gender:Male
  • Location:Northeast

Posted 17 December 2017 - 23:00

 

I only have 4 hours in a jetbuggy but 2,000hrs in 58s.  There is definitely a 5 minute limit on power over 85% tq in the 58.  Not sure why it would be any different in the jetbuggy.

 

 

VNE with takeoff power applied (85-100% torque) in the B206B3 is 80 knots.  It's in the airspeed limitations section.  Although they are very similar, there are quite a few differences between the Jet Ranger and an OH-58.


Edited by SBuzzkill, 17 December 2017 - 23:00.


#14 Nearly Retired

Nearly Retired

    VR Veteran Poster

  • VR Member
  • PipPipPipPipPipPipPip
  • 589 posts
  • Gender:Male
  • Location:Pensacola, FL
  • Interests:Well, obviously flying and anything aviation...but motorcycling as well. And drinking (when I'm not riding of course!). Oh, and Facebook. Always on Facebook (Bob Barbanes).
  • Company working for:Golden Wings Aviation, Brewster, WA (part-time)

Posted 18 December 2017 - 11:02

Hmm.  It is true that the airspeed limit above 85% torque is a fairly recent thing.  "Fairly" when you consider that the 206 has been out since the mid-1960's and the restriction came out, like 40 years later.  Like others, I was told by Bell that it has to do with mast bending with forward cyclic as the horizontal stab tries to pull the tail down in cruise.

 

That said, I believe this might be a case of the Maintenance Manuals not catching up to the RFM.  Yes, the airspeed restriction does constitute a "Limitation."  But so does VNE, by the way.  What inspection is required if you exceed VNE?  Umm, none.  Maybe this is just one of those things where Bell figures that hey, if you routinely exceed this airspeed limitation then you may find yourself getting more trans chips and the mast/trans may not make it to TBO?  Maybe they figured that no specific inspection was called for, and deliberately decided to not include one in the M&O?  I doubt (in my most humble pilot opinion) that it could lead to a catastrophic trans failure, but you never know.  

 

My immediate question upon reading Whistler's post was: Why are the pilots doing power checks at such high airspeed?  I always do them at 60 knots where the ship is nice and stable-ish.  Intentionally doing them at high-cruise tells me that the 206 pilots don't know what they're doing. (Which begs the question: Do the other Astar pilots know what they're doing either?)

 

I was going to suggest that perhaps it's a good reason for Whistler not to fly those 206's.  But then I thought, well, with leadership like that, should Whistler even be working for that company at all?  Probably not.  The Chief Pilot cannot be very sharp if he's hiring goobers to fly his 206's.  Which then tells us other things about the operation.

 

But instead of Whistler just throwing down his headset and stomping off into the sunset, is there another way?  We all have *our* limitations.  We all have to know when to say "when."  As one of my wise mentors said to me once, "Hey, I may do it with a crayon, but I have to draw the line somewhere."



#15 helonorth

helonorth

    VR Veteran Poster

  • VR Member
  • PipPipPipPipPipPipPip
  • 1,041 posts

Posted 18 December 2017 - 11:24

The Bell 206B flight manual states:

 

"85 to 100% TORQUE TAKEOFF POWER RANGE

 

Vne 92 MPH IAS (80 KIAS)."

 

There is nothing stated that says you can do this for 5 minutes. Yes, you have exceeded a limitation if you exceed 80 KT with over 85% Torque for ANY length of time. It's that simple. 


Edited by helonorth, 18 December 2017 - 13:03.

  • Wally and 500F like this

#16 helonorth

helonorth

    VR Veteran Poster

  • VR Member
  • PipPipPipPipPipPipPip
  • 1,041 posts

Posted 18 December 2017 - 16:58

If I remember correctly, unless you were at a pretty high altitude, you can't plot your numbers on the chart with a lower power setting.  Under most conditions, 60KTS will not work. You had to get the TOT up to get on the chart. A torque setting for 60KTS wouldn't do it.

 

Is somebody not aware that VNE is a limitation due to retreating blade stall? I have never even come close to reaching VNE in a 206.


Edited by helonorth, 18 December 2017 - 17:01.


#17 Nearly Retired

Nearly Retired

    VR Veteran Poster

  • VR Member
  • PipPipPipPipPipPipPip
  • 589 posts
  • Gender:Male
  • Location:Pensacola, FL
  • Interests:Well, obviously flying and anything aviation...but motorcycling as well. And drinking (when I'm not riding of course!). Oh, and Facebook. Always on Facebook (Bob Barbanes).
  • Company working for:Golden Wings Aviation, Brewster, WA (part-time)

Posted 18 December 2017 - 18:11

Helonorth, no, I didn't say that I use 60 knot power.  I hold 60 knots and pull to a limit (usually torque), and then let it climb while I record the numbers.  Seems to have worked for me and I can always at least get on the chart.  Remember, I fly in the southern U.S., not Alaska.

 

As far as VNE... you've never done a cruise-descent?  One time in a little 206B out in the Gulf of Mexico I went to duck under a very low roll cloud which was part of a long line of clouds that stretched across my flight path.  I could see from the reflection on the water that it was sunny on the other side of the line, and I needed to go thataway, so...  Down we went. I had to get down to about 300' to do it.  A PHI B-model only cruises around 103 knots, so even our dive only had the a/s up to around 120, still well under VNE.

 

Just as I was about to go under the clouds (in a dive), I heard something strange.  It was wind noise.  I looked over and saw the airspeed needle *WELL* above the redline!  And I mean, OH MY GOD above it.  I thought, "Gee, I've never seen that before!"  There was apparently some funneling effect with the wind as it moved from one pressure area to another.  GOM weather is strange sometimes.

 

Once on the other side of the little line of clouds I raised the nose and the airspeed immediately returned to normal.  The helicopter did not explode.  But it sure was weird!  


  • Wally, SBuzzkill, 500F and 1 other like this

#18 Eric Hunt

Eric Hunt

    VR Veteran Poster

  • VR Member
  • PipPipPipPipPipPipPip
  • 831 posts
  • Gender:Male
  • Location:Near the beach

Posted 20 December 2017 - 06:23

The 5 minute limit is for using power in the yellow band, between 85% and 100%.

 

The speed limit is when using power above 85%.

 

There is no time limit on speeds, only power settings.


  • 500F and WolftalonID like this

#19 WolftalonID

WolftalonID

    VR Veteran Poster

  • VR Member
  • PipPipPipPipPipPipPip
  • 582 posts
  • Gender:Male
  • Location:New Meadows, ID
  • Interests:Flying, helicopters, back country, archery elk hunting, wood working!
  • Company working for:Mildly experienced stick wiggler/rookie expert

Posted 22 December 2017 - 11:35

Mike...I guess my avatar accolades are misunderstood. Cheif flight instructor/135 pilot probably should read Chief flight instructor for the flight school of our company/line pilot on charter/tour/film flight line. And therefore its been updated to reflect my experience more precisely. ;)

We have three companies in one, Charter/School/Maintenance The company Chief Pilot is the 135 Company Check airmen or lead check airmen. Also a DPE.

My reference to the issue at hand came from speaking to our DOM as well we have a close... very close relation with Bell. Sure there was an exceedence, never said not to speak up about it. I simply said no mention of what to do about it leaves your DOM at his own discretion on how to proceed.

Its like in school students read in their Robinson POH, blades must turn within 5 seconds of clutch engagement. So when it takes 8 seconds they shut her down and run in saying OMG!! we are gonna die cant fly it.

Yet in reality, there is a specific runout time Maintenance manuals give, and when within that limit the 5 second rule is overridden. No pilot knows this unless they read it themselves or are shown by Maintenance.

Sometimes certain limits are there simply to provide the necessary window for component life limits, not because its gonna explode on ya.

Serious limit exceedance occurrences are definitely listed with replacement and maintenance schedules. Calling your OEM everytime something is not listed is about as effective as going to WebMD for a diagnosis..your going to end up in the ER regardless...paper cut, sliver, broken bone...yet we have experienced life enough to know how to address certain issues. So has a well seasoned DOM.

Now that said, there are better ways to do things, such as power checks, and there are several ways to skin a cat. Some are effective and yield possitive results, some are effective and may cause damage too, some ways are just plain retarded.

My opinion from asking and learning from those that know more about maintenance and repair than I do, and trust based on how particular their standards are to begin with in all other areas of maintenance observed, the ship is most likely perfectly unharmed. But..retrain expected proceedures for future longevity concerns for the ships.

Edited by WolftalonID, 22 December 2017 - 11:41.

Sometimes we think we know it all....only later to discover we only knew all we had learned. Never stop learning.

#20 Rotorhead84

Rotorhead84

    VR Veteran Poster

  • VR Member
  • PipPipPipPipPipPipPip
  • 148 posts
  • Gender:Male

Posted 27 December 2017 - 09:15

 

 

VNE with takeoff power applied (85-100% torque) in the B206B3 is 80 knots.  It's in the airspeed limitations section.  Although they are very similar, there are quite a few differences between the Jet Ranger and an OH-58.

 

interesting.  Thanks for the info.  Now I'm curious






0 user(s) are reading this topic

0 members, 0 guests, 0 anonymous users



Genesys VR Forum 200PrecisionVRForumHome200HeliHelmets-VR HomeSpectrum_VRHome200Praetor_Home200MaunaLoaVRHome200LORD_VRHome200NFCVRForum200HomeBE_VRHome200