Dear all, I have been looking through this thread on a regular basis and found the discussion points re the S92 extremely interesting and the technical advisories informative, and thanks to all for that.
With developments recently discussion is bound to move towards one area of interest, this being the transmission and the lubrication system. Though no official finding has been released this area seems to be of particular interest in the so recent tragic event affecting our colleagues and friends in St John’s. This being the case I hope that I can make some general and personal comments regarding what is in my view a critical system and how I had expected design concepts to have ensured continued safe operation, development of emergency procedures that prevented catastrophic failure.
When I started my involvement with off shore commercial helicopters it was the S61, this was before the emergency lube system was installed and the effect of a lubrication failure was hammered home during the technical training, white metal input bearings only work when lubricated, loss of lubrication resulted in the input shaft failure and possible exiting from the GB. Your only decision was down and you hoped that you made it before the transmission failed. When the emergency lube system was installed (lubricating the Input bearings if you had oil) you had a fighting chance of, making a safe landing.
Now we have the new generation of helicopters and a so called safety culture however the basics still apply, oil is needed to lubricate and cool. The illusion that a gearbox will continue and is guaranteed to perform safely for a limited period of time (30 minutes on the AW 139) with no or very low oil pressure is in my view a myth if you look on this as a guarantee to continue on to reach the beach or extend the time frame. The tests are carried out in ideal conditions and may not represent all conditions of system failure or GB condition. It may give a comfort factor though during a decent to a safe altitude and a point when a final decision can be made, low slow and ready or to land. I still remember the definition of “Land Immediately” and the decision responsibility that the commander was expected to take. I also remember the debriefing and questions from individuals who had the benefit of hind sight.
The S92 seems to me to be a great helicopter, lots of really cool electronics plenty of power and lovely flat screen displays, just like the AW 139, but, has the mechanical bit been developed to match. I think not.
That’s it from me;
I am so pleased that I had the opportunity to experience the new technology and progress at the twilight of my time in the industry, but so sad that I am still seeing failure and death from mechanical systems that have plagued me over the past 40 years.
Safe Flying and Blue Skyes.
Outhouse