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AS350 swashplate bearing HOT

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AS350 swashplate bearing HOT

Old 29th Jul 2017, 18:58
  #21 (permalink)  
Join Date: Mar 2009
Location: Canada
Age: 60
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Originally Posted by rotorfan View Post
I agree with riff_raff, and would even modify his statement by saying 180degF would be too hot for anyone to touch.

I work on high precision machining equipment for my business. While touring a machine with a new [email protected] thermometer in hand, I was checking the temps of all sorts of mechanisms. I was particularly interested in the hydraulic system, knowing from too many experiences that pumps and valves had inflicted pain. What's this? Only 125degF (52C) hurt enough that I couldn't touch it for 2 seconds without yanking my hand away. I was fascinated to realize how little above our body temperature was the threshold of pain. It's also interesting that poking my finger in a cuppajoe might feel hot, though it might not be as hot as I prefer to drink it.

As riff_raff says, it may seem quite hot to our touch, and yet nothing to tough steel. It needs to be actually measured and then investigated. Feeling hot to the touch could mean 130 or 530, just irrelevant.
Not unusual for a swashplate to run hot especially after being lubricated or newly installed. Hot to the touch means nothing. Easy enough for maintenance to check the condition of the bearing by disconnecting the pitch links, drive link and spinning the rotating ring. Nothing wrong with being cautious but you should be offered an explanation. The three I usually offer up are, "they're all like that", "it's the gauge" or "I can't fix it".
Wiggins61 is offline  
Old 29th Jul 2017, 19:06
  #22 (permalink)  
Join Date: Apr 2003
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Wiggins61 is right, on all counts. The grease lubed roller or ball bearings can get to about 250 to 300 degrees and still be very happy. The limit, based on the type of grease used, can be a temperature that will blister your finger. That doesn't mean this is normal for your type, so there is nothing wrong with personally discussing your observations with the maintenance chief, and even a wander thru the maintenance manual.
NickLappos is offline  
Old 30th Jul 2017, 05:51
  #23 (permalink)  
Thread Starter
Join Date: Jul 2017
Location: Australia
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I was hoping to receive advise from experienced AS350 operators.
So far not one reply.
Even the reverent Mr Lappos appears to have no knowledge of the operating requirements of the as350.
Every rotorcraft on the Australian register has a placard on the instrument panel stating that the rotorcraft MUST be operated IAW the approved flight manual.
The AS350 flight manual is clear in its requirements for after the last flight of the day checks.

Swashplate Bearing: check to be performed within five minutes after rotor stops.....No abnormal heating felt when touched with hand, no grease runs, no change in colour, no scaling of paint.

So, what is abnormal?
If a prudent pilot performed this check after the last flight of the day, as the RFM mandates, he would soon learn that under normal operating conditions his swashplate would NOT be HOT to the touch. Not hot is normal.
Hot is abnormal.

In my case the chief pilot is also the maintenance controller and company owner. He is a standover man. A bully and a tyrant with a propensity for violent outbursts. He holds the maintenance provider over a barrel by way of unpaid invoices.

So, once again I'll ask the question.......

What would you do?
Mutant Mthfr is offline  
Old 30th Jul 2017, 07:08
  #24 (permalink)  
Join Date: Jul 2002
Location: UK
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Get a job elsewhere.
Bravo73 is offline  
Old 30th Jul 2017, 08:14
  #25 (permalink)  
Join Date: Feb 2014
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Jeez Mutant, this thread drift went on regarding the temp limitations and technicals etc etc. But the bottom line was, what would you do?

Better to be unemployed than dead. Better still to let other people know rather than have blood on your conscience from something you knew wasn't right.

Now, just deal with it, as I mentioned before this isn't the first time you've posted a similar experience.

P.s if you're on the Gold Coast I know exactly who you mean.
Frying Pan is offline  
Old 30th Jul 2017, 09:09
  #26 (permalink)  
Join Date: Jul 2014
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Originally Posted by Mutant Mthfr View Post
I was hoping to receive advise from experienced AS350 operators.
So far not one reply.


In my case the chief pilot is also the maintenance controller and company owner. He is a standover man. A bully and a tyrant with a propensity for violent outbursts. He holds the maintenance provider over a barrel by way of unpaid invoices.

So, once again I'll ask the question.......

What would you do?
I hope you'll have the specialized reply you want... but sincerely, the problem here is not if the swashplate is hot (you have the manual and you already know that it is abnormal, ¿right?). The point is that you are a pilot and you have lost confidence in the maintenance system and management in your company. This is a bad situation for all the involved here. You end up thinking that something bad can happen, which puts a lot of stress on you and even fear every time you here a noise from above (I have passed through this). On the other hand, pilots with no confidence in the maintenance systems ara soon tagged as "picky" pilots and are really difficult to handle by the management.

You should look for a job in another company before they fire you.
palacio802 is offline  
Old 30th Jul 2017, 17:36
  #27 (permalink)  
Join Date: Oct 1999
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A general but very specific question is asked here, without the appropriate qualifying reference that the OP already has at hand. If you wanted to get a better take on the situation then you might have provided this information from your Flight Manual at the first instance, instead of promoting responses then critiquing them?

I would always recommend that discussing an item is discussed with your maintainer prior to writing it in the book. However, if it is a defect, I know of no Aviation Regulatory system that allows you to NOT record it in the logbook; with the appropriate rectification/action being accomplished and returned to service by an appropriately authorized person prior to any further flight. I do know of companies getting audited and found to have no defect or rectification entries in their logbooks being an immediate red-flag that there is either a secondary recording system or an alternative systemic culture of the internal process of managing the maintenance of the machine and the personel within the organization. If a review of the maintenance logbook reveals parts changes that could only have been detected in flight and no other entries have been made, you need to look very closely at the entire operation, management, processes and policies that exist. Remember, that if you are the Pilot and are not following the regulatory process, you may be left as the one holding the bag!

If you don't have the answer and your maintenance provider doesn't have the answer then you need to escalate the quest for definitive information. In this instance contact the OEM through your local Tech Rep. To ensure you always get a response do it in writing. In this specific maintenance instance, I can assure you that you are playing with fire. I can also assure you that the OEM will have some very specific recommendations for you. I can also eassure you that your Regulatory organization will have some very specific actions to bring you (as well as your employer) back into line.

More simply. Do you want to die? If you're working in an organization that operates in this manner, it can only operate this way with your complicit participation!

In the meantime, read this report and understand WHY this warning is in your AFM. This was a tragic and very avoidable loss.


Last edited by Cyclic Hotline; 30th Jul 2017 at 19:25.
Cyclic Hotline is offline  
Old 3rd Aug 2017, 03:14
  #28 (permalink)  
Join Date: Apr 2014
Location: The Americas
Posts: 33
As yes , the "mom and pop" operation. Third party maintenance. Pop wears all the "regulatory title" hats, mom runs the books and the office. Economic realities dictate that nuisance snags are dealt with in "non textbook ways"
Pop may be a tyrant but he is probably well aware of the economic realities that come along with a fatal accident , remind him of this. That said , if your knowledge on type comes even close to his, run away as fast as you can. If his operational experience far outstrips yours. Listen, but always question.

It's been about 8 years since I last put a AS350 to bed, but as previously mentioned after fresh grease, I remember the swashplate check being a pat at most due to temperature. Seeing as it sounds like your maintenance department is non existent, I'd buy a handheld IR thermometer gun to quantify the temperature value creating your own standardized practice on post shutdown for your own peace of mind. A good tool to have in your "hat rack tool box" when operating in remote environments. If you have a open circuit in a oil temperature gauge, which causes it to peg to the high side. You 'll at least have a clue to the temperatures involved when troubleshooting.

Have fun. Paranoia can save your life, just make sure it doesn't get clinical.
Washeduprotorgypsy is offline  
Old 3rd Aug 2017, 14:21
  #29 (permalink)  
Join Date: Dec 2005
Location: England
Posts: 1,329
Temperature is not normally something that is measured from a maintenance point of view. I have never seen any limits mentioned in a manual for a swashplate. Not to say that is definitive.

Normal maintenance action would involve greasing and checking the outgoing grease for contamination, metal or other debris. Other checks would be visual including paint discolourisation, rotational roughness check including break out forces and checking for play.

As too temperature itself. Aeroshell 22 which is a common grease used in swashplates has an upper temperature limit of 204 deg C. So the temperature needs to be under that. The rest depends on what the swashplate is made from. The bearings themselves being steel will stand quite high temperatures. The body could well be alumininum alloy and be more susceptable to temperature. Aluminium alloy for high temperature use falls into between 260-370 deg C. I would hazard a guess that material used for swashplates falls somewhere in that band.

So I would sugest that the grease and it's operating temperature is the limiting factor.

Then Bell 206 engine driveshaft (all steel) does have temperature monitoring. Originally temperature indicating tape and now a band of green primer paint. The paint changes colour from green to brown at about 300 deg C. If you are unfortunate to have suffered a fire affecting the aircraft structure a quick check is to look at the aircraft primer internally, if brown you have a problem. Conductivity checks should be carried out in any case.

Last edited by ericferret; 3rd Aug 2017 at 19:41.
ericferret is offline  
Old 6th Aug 2017, 05:10
  #30 (permalink)  
Join Date: Sep 2007
Location: USA
Posts: 602
The link provided by CH above mentions the swashplate bearing should have been greased every 400 hrs per OEM, and every 100 hrs per operator's procedure. The swashplate bearing failure in this case apparently seized due to lack of lubrication/overheating just 1.2 flight hours after the last 100 hr inspection of the swashplate was scheduled per company procedures.

One thing that should be looked for when adding grease to rolling element aircraft bearings is any metallic debris within the old grease pushed out from inside the bearing. A properly designed bearing grease circuit will allow the fresh grease to completely displace the old grease from inside the bearing internal volume, along with any debris, moisture or contaminants. Obviously, this requires a significant amount of grease to be injected at one end, a discharge port at the opposite end to allow the old grease to exit, and an effective set of bearing seals in between to prevent leakage.

In this particular case, it should have been obvious visually if there was sufficient leakage of lubricant past the bearing seals to produce this type of failure within the limited amount of flight time since the last scheduled inspection. The report also states the bearing materials had a blue tint, which would indicate they were heated to a temperature close to 600degF. This is well above the safe operating temperature of conventional bearing steel alloys.
riff_raff is offline  
Old 6th Aug 2017, 22:25
  #31 (permalink)  
Join Date: Oct 2012
Location: vancouver
Age: 54
Posts: 55
Aeroshell 22 which is a common grease used in swashplates
Aeroshell 7 is the only grease authorized for the AS350 swashplate. If it's too hot to the touch, you more than likely don't have enough grease in there. Give it a couple of shots of grease and see what comes out. Or how many pumps it takes before grease starts to come out.
helicopterray is offline  
Old 22nd Sep 2017, 16:07
  #32 (permalink)  
Join Date: Sep 2017
Location: Canada
Posts: 338
You're going to want your maintenance staff to refer to SB 62-00-12 and 62-00-17, although older documents, they will provide guidance on what the definition is on a hot swashplate. Basically they say if you can't keep your hand on it, it's too hot.
If your swashplate is recently overhauled or new bearing installed, there are criteria specifically mentioned in the maintenance documentation that they should be following such as rotational drag.
Experience tells me that if the graphoil is applied to thick (exceeds two light crosscoats and is transparent, then the bearing will be tight and fail the rotation drag check, and thus will run hotter than it should.

So, your determination of "too hot" is based on keeping your hand on the swashplate.
Can't do it, ground the aircraft.
GrayHorizonsHeli is offline  
Old 23rd Sep 2017, 15:40
  #33 (permalink)  
Join Date: Mar 2006
Location: uk
Posts: 144
Be careful, checked on my AS355 the other day and bearing was barely warm
to touch after one hour flight!
claudia is offline  

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