North Sea heli ditching: Oct 2012
Join Date: May 2012
Location: Aer
Posts: 431
Likes: 0
Received 0 Likes
on
0 Posts
As predicted.....
EASA AD No.: 2013-0113-E
So now, the EC225 has lost its 30 minute "run dry" capability.
EASA AD No.: 2013-0113-E
The Emergency Lubrication (EMLUB) system of the helicopter was designed to
guarantee 30 minutes of continued safe flight in the event of total loss of the
dual oil lubrication system of the Main Gearbox (MGB).
Investigations on the EMLUB system have revealed an area of the flight
envelope in which the emergency lubrication Glycol pump’s performance is
different to that assumed during certification.
Consequently, even though the likelihood of using the EMLUB is extremely low
(no total loss of oil lubrication encountered on the Super Puma fleet), as the
continued safe flight of 30 minutes is not guaranteed in the whole flight
envelope, and pending a Eurocopter modification to the Glycol pump and
EMLUB pressure switches, an immediate landing or ditching is required as
soon as the EMLUB system is activated.
To address this potential unsafe condition, Eurocopter issued EC225
Emergency Alert Service Bulletin (ASB) No 04A010 to provide updated
Rotorcraft Flight Manual (RFM) emergency procedures.
For the reasons described above, this AD requires amendment of the RFM
emergency procedures section.guarantee 30 minutes of continued safe flight in the event of total loss of the
dual oil lubrication system of the Main Gearbox (MGB).
Investigations on the EMLUB system have revealed an area of the flight
envelope in which the emergency lubrication Glycol pump’s performance is
different to that assumed during certification.
Consequently, even though the likelihood of using the EMLUB is extremely low
(no total loss of oil lubrication encountered on the Super Puma fleet), as the
continued safe flight of 30 minutes is not guaranteed in the whole flight
envelope, and pending a Eurocopter modification to the Glycol pump and
EMLUB pressure switches, an immediate landing or ditching is required as
soon as the EMLUB system is activated.
To address this potential unsafe condition, Eurocopter issued EC225
Emergency Alert Service Bulletin (ASB) No 04A010 to provide updated
Rotorcraft Flight Manual (RFM) emergency procedures.
For the reasons described above, this AD requires amendment of the RFM
So now, the EC225 has lost its 30 minute "run dry" capability.
More good news on the 225 design.....why only the sound of Crickets from the EC Lovers?
I am not knocking the Helicopter....just the lack of impartiality on those who love to criticize the 92 all the while bragging on the 225.
As I have said recently.....the Certifying Authority that approves the Type Certificate need to do a better job of things.
If one is to assert a "Run Dry" capability....it must be "Run Dry"....no liquids of any kind.....the worse case scenario and not some construct that affords the MGB a "Crutch" to meet the requirement.
Neither the 92 or the 225 would pass the test.....and probably never shall if an actual dry gearbox condition was the criteria.
I am not knocking the Helicopter....just the lack of impartiality on those who love to criticize the 92 all the while bragging on the 225.
As I have said recently.....the Certifying Authority that approves the Type Certificate need to do a better job of things.
If one is to assert a "Run Dry" capability....it must be "Run Dry"....no liquids of any kind.....the worse case scenario and not some construct that affords the MGB a "Crutch" to meet the requirement.
Neither the 92 or the 225 would pass the test.....and probably never shall if an actual dry gearbox condition was the criteria.
So it is possible for the crew to understand the HUMS as suggested if there is enough commercial pressure & corporate angst.
"For aircraft equipped with HUMS, our aim is that the on-board shaft monitoring will in itself be sufficient to enable the authorities to lift the flight restrictions over hostile terrain."
"For aircraft equipped with HUMS, our aim is that the on-board shaft monitoring will in itself be sufficient to enable the authorities to lift the flight restrictions over hostile terrain."
SASA, I suppose its because we all knew there were some issues with the Emerg Lube, this is no surprise. Yes its frustrating that EC seem to have got this wrong in a number of ways, on the other hand at least they tried, unlike their opponents to tried to bull**** their way around it!
I am with you on the qualtiy of the certification process. Very slow, expensive and bureaucratic but with no guarantee of an airworthy helicopter at the end of it. Why bother?
You should however bear in mind that there is no requirement for "run dry" in the certification rules, merely continued operation after a major oil leak resulting in loss of all oil. Whilst you might think run dry is a good idea, for large helicopters heat dissipation is a big deal. To make the gearbox able to cope would almost certainly require big compromises in design in terms of weight, complexity and cost. If you bear in mind that in the entire history of the Super Puma family there has never been a total oil loss event, just how much extra complexity do you want to introduce to make it "dry run". You might find that in terms of overall safety, your requirement actually reduces safety taken in the context of dry run never actually being required. Anyway, surely it would be better to expend your energies ensuring that the heli doesn't lose all its oil in the first place?
500e - Yes, I think so. The plan is for a warning light and plain text message to illuminate showing the threshold value and the current value (greater than the threshold value presumably), perhaps with the time of detection or time elapsed since detection. There will be no judgement required, it will be "black and white".
I am with you on the qualtiy of the certification process. Very slow, expensive and bureaucratic but with no guarantee of an airworthy helicopter at the end of it. Why bother?
You should however bear in mind that there is no requirement for "run dry" in the certification rules, merely continued operation after a major oil leak resulting in loss of all oil. Whilst you might think run dry is a good idea, for large helicopters heat dissipation is a big deal. To make the gearbox able to cope would almost certainly require big compromises in design in terms of weight, complexity and cost. If you bear in mind that in the entire history of the Super Puma family there has never been a total oil loss event, just how much extra complexity do you want to introduce to make it "dry run". You might find that in terms of overall safety, your requirement actually reduces safety taken in the context of dry run never actually being required. Anyway, surely it would be better to expend your energies ensuring that the heli doesn't lose all its oil in the first place?
500e - Yes, I think so. The plan is for a warning light and plain text message to illuminate showing the threshold value and the current value (greater than the threshold value presumably), perhaps with the time of detection or time elapsed since detection. There will be no judgement required, it will be "black and white".
Last edited by HeliComparator; 29th May 2013 at 13:50.
If you bear in mind that in the entire history of the Super Puma family there has never been a total oil loss event, just how much extra complexity do you want to introduce to make it "dry run".
You should however bear in mind that there is no requirement for "run dry" in the certification rules, merely continued operation after a major oil leak resulting in loss of all oil.
Page 3 of their S2-2013 report...
" MGB certification requirements
The EC225 LP was certified by the European Aviation Safety Agency (EASA) against the Joint Aviation Regulations (JAR) 29. The regulations require the helicopter to continue safe flight, at prescribed torque and main rotor speeds, for at least 30 minutes following the loss of the MGB lubrication system. This is met on the EC225 LP with an emergency lubrication system thatuses a mixture of glycol and water, called Hydrosafe 620, which cools and lubricates the MGB."
and doesn't CS29 state:-
"Category A. Unless such failures are extremely remote [1 x 10-7 per FH], it must be shown by test that any failure which results in loss of lubricant in any normal use lubrication system will not prevent continued after operation, although not necessarily without damage, at a torque and rotational speed prescribed by the applicant for continued flight, for at least 30 minutes after perception by the flight crew of the lubrication system failure or loss of lubricant."
So what happens now?
There is no way ANY modern gearbox can run for thirty minutes without any lubricant. They might have done decades ago when they were built by Swindon Railway Works but not now.
Should you want to run it for thirty minutes you have got to put in an alternative lubrication system which as far as I can see the EMERLUB is as a good attempt as any. The design caters for both pressure failure and quantity failure and it has worked on both of the recent ditchings. The only problem was that the crew were told it wasn't working which is why they ditched. With a serviceable system both aircraft were likely to have made landfall and this whole scenario would not have arisen.
They did not ditch as a direct result of oil pressure failure.
You have a situation now where an aircraft is not permitted to fly because of a failure of an emergency system when other aircraft without any comparable system are deemed safe to continue.
The mistake was putting both pumps on the same driveshaft. They should have left the main pump on the LH Accessory drive as it is on the 330.
Should you want to run it for thirty minutes you have got to put in an alternative lubrication system which as far as I can see the EMERLUB is as a good attempt as any. The design caters for both pressure failure and quantity failure and it has worked on both of the recent ditchings. The only problem was that the crew were told it wasn't working which is why they ditched. With a serviceable system both aircraft were likely to have made landfall and this whole scenario would not have arisen.
They did not ditch as a direct result of oil pressure failure.
You have a situation now where an aircraft is not permitted to fly because of a failure of an emergency system when other aircraft without any comparable system are deemed safe to continue.
The mistake was putting both pumps on the same driveshaft. They should have left the main pump on the LH Accessory drive as it is on the 330.
Join Date: Nov 2008
Location: UK
Posts: 188
Likes: 0
Received 0 Likes
on
0 Posts
There is no way ANY modern gearbox can run for thirty minutes without any lubricant. They might have done decades ago when they were built by Swindon Railway Works but not now.
Some of the time is of course with lub, but for how long? I would say max 5-10 min.
HC; I am amazed at your change of stance. As SASLess said, there was a lot of (justified) uproar when the S92 did not show compliance with the rule.
A total loss of oil may not have happened with the 332 fleet (yet) but it did happen to the S92 - twice. Equally, the S92 has not had a main shaft fracture but there have been two with the EC225.
SASLess; as you well know, 'run dry' is a colloquial term for continuing to function after losing the oil in any one of the qualifying gearboxes. Showing compliance with an 'auxiliary cooling system' is well within the rules.
As you have both pointed out, the acceptance of a 'failure to show compliance' on one hand and a failure to 'demonstrate' compliance with a fitted system on the other, does not show the Certifying Authorities in a good light.
The bottom line, however, rests with the manufacturers who should have satisfied themselves about the efficacy of their systems before offering them, as compliant, to the Authorities.
The expertise is contained within the manufacturer's organisation, not in the Authority's.
A total loss of oil may not have happened with the 332 fleet (yet) but it did happen to the S92 - twice. Equally, the S92 has not had a main shaft fracture but there have been two with the EC225.
SASLess; as you well know, 'run dry' is a colloquial term for continuing to function after losing the oil in any one of the qualifying gearboxes. Showing compliance with an 'auxiliary cooling system' is well within the rules.
As you have both pointed out, the acceptance of a 'failure to show compliance' on one hand and a failure to 'demonstrate' compliance with a fitted system on the other, does not show the Certifying Authorities in a good light.
The bottom line, however, rests with the manufacturers who should have satisfied themselves about the efficacy of their systems before offering them, as compliant, to the Authorities.
The expertise is contained within the manufacturer's organisation, not in the Authority's.
Last edited by JimL; 30th May 2013 at 07:15.
The usage of the "colloquial 30 Minute Run Dry Capability" may very well have led to the fatalities in the Cougar Crash off Newfoundland....and the Industry, Operators, Builders, and Certifiers all need to settle the issue with finality and very accurately define what "Run Dry" capability a Gearbox actually has using the Worst Case Scenario....and not some contrived notion that shows a capability that is not always accurate.
Join Date: Oct 2002
Location: 1 Dunghill Mansions, Putney
Posts: 1,797
Likes: 0
Received 1 Like
on
1 Post
For anyone interested in the general topic of how OEMs justify these claims, Kawasaki Heavy Industries presented a paper on Upgrade of Loss of Lubricant Operation Capability for EC145T2 (BK117 D-2) Main Gearbox at last week's AHS Forum 69, bascially an explanation of the testing done to demonstrate a 30-minute dry-run capability. The paper should be available via the AHS online store shortly.
I/C
I/C
Fareastdriver, there is some work going on with superfinishing gears that may render your opinion moot. As I have only partial knowledge, I'll let it go at that.
Pitts - I suppose you could say REDL was a total loss of oil event, but that was the least of the problem and of course no run dry capability would have made the slightest difference.
Jim - no change of stance from my perspective. My beef about the 92 was primarily about the deceit in pretending it was the safest helicopter ever built and fully compliant with the relevant version of FAR29 when in fact there was fudging going on. And a reluctance for the then programme manager to tell the whole story.
I was quite happy flying the 332L for many years. And of course a facet of the current 225 debacle is that our crews are now flying around in 332Ls again, with no pretence of 30 mins "run dry". They are unhappy because of the step backwards in automation, speed, comfort and range /payload but not for the lack of 30 mins dry run.
I see 30 mins run dry as a "nice-to-have", not the be all and end all. 30 mins at 80kts doesn't necessarily get you to somewhere dry to land. Better to avoid loss of oil in the first place, eg by well designed oil systems (and filter housings!)
Jim - no change of stance from my perspective. My beef about the 92 was primarily about the deceit in pretending it was the safest helicopter ever built and fully compliant with the relevant version of FAR29 when in fact there was fudging going on. And a reluctance for the then programme manager to tell the whole story.
I was quite happy flying the 332L for many years. And of course a facet of the current 225 debacle is that our crews are now flying around in 332Ls again, with no pretence of 30 mins "run dry". They are unhappy because of the step backwards in automation, speed, comfort and range /payload but not for the lack of 30 mins dry run.
I see 30 mins run dry as a "nice-to-have", not the be all and end all. 30 mins at 80kts doesn't necessarily get you to somewhere dry to land. Better to avoid loss of oil in the first place, eg by well designed oil systems (and filter housings!)
Last edited by HeliComparator; 29th May 2013 at 22:23.
How would G-REDL be viewed?
As that accident was from a completely different MGB failure it is still relevant to the MGB issues confronting EC currently.
Public Opinion....especially that of the people who ride as passengers in the aircraft is influenced by all of these events and has to be considered when Operators consider all the issues surrounding which aircraft to buy, offer on contract, and invest very large sums of money to field.
Public Opinion....especially that of the people who ride as passengers in the aircraft is influenced by all of these events and has to be considered when Operators consider all the issues surrounding which aircraft to buy, offer on contract, and invest very large sums of money to field.
HC
Thanks for reply.
"500e - Yes, I think so. The plan is for a warning light and plain text message to illuminate showing the threshold value and the current value (greater than the threshold value presumably), perhaps with the time of detection or time elapsed since detection. There will be no judgement required, it will be "black and white".
18 months or so ago when I made the suggestion regarding some form of HUMS information for the crew & was told much to complicated for them to understand, now that it impinges on the bottom line of a multinational it would appear to be doable.
Thanks for reply.
"500e - Yes, I think so. The plan is for a warning light and plain text message to illuminate showing the threshold value and the current value (greater than the threshold value presumably), perhaps with the time of detection or time elapsed since detection. There will be no judgement required, it will be "black and white".
18 months or so ago when I made the suggestion regarding some form of HUMS information for the crew & was told much to complicated for them to understand, now that it impinges on the bottom line of a multinational it would appear to be doable.
Last edited by 500e; 30th May 2013 at 09:47.
...and in no way shape or form connected to this discussion
From that report:-
7.4.1 Civil approach to certification of lubrication system
The testing of the lubrication system is explained in CS29.927 “Additional Tests” Part (c) which gives the requirement for 30 minutes continued operation after “perception by the flight crew of the lubrication system failure or loss of lubricant”. However, this requirement may be “bypassed” if it is shown that such a failure is extremely remote, i.e. 1 x 10-7 per hour or better.
Last edited by Pittsextra; 30th May 2013 at 10:20.
Would be interesting to know what the 'area of the flight envelope' is to better understand its probability and criticality.