Squib66
You got me going back over old posts from the main S92 thread. Here's some extracts that caught my eye:
The S-92 has 4 main rotor blades (last time I counted) and will have them for the next decade, anyway. The vibration is very nice, thank you, with levels that are better than the President's S-61, thanks to the 4 (that's four) main rotor blades, and also the very good computer driven vibration absorber system that we use.
IMO the S92 vibrates worse than any helo I've flew in over 20 years. Linked to MRGB mounting feet cracks, accelerated fatigue of titanium studs?
Breaking new ground for medium-weight helicopters, the S-92 provides unprecedented levels of safety and reliability. It is the only aircraft in its class certified to the latest specifications for flaw tolerance, bird strike capability and turbine burst protection. In addition to its civil helicopter capabilities, the rotor system and dynamic components are designed to meet the UH-60 BLACK HAWK ballistic tolerance requirements and all gearboxes are capable of running 30 minutes after loss of oil. Corrosion protection meets or exceeds current maritime standards
Note the highlighted wording, doesn't say run-dry but does refer to the UH-60 which apparently does have 30-minute run dry time capability. This statement was the one issued by SAC post-FAA certification approval.
It was the fastest, cleanest certification anyone at Sikorsky can remember. The first certification data flight was made last December, the FAA got on board in September, and we were done with all flights exactly one year later, Dec 12. The data was all processed in real time, so the FAA was ready to sign on Dec 17 (Wright Brothers day!) so they did. Not a bad data point in the thousands taken.
Perhaps in hindsight too fast considering some of the base errors we now unfortunately know about.
The "regular" Sikorsky military design rules were also met, including ballistics and object strikes, since we intend to use the whole drive train (engines, transmissions, rotors and blades) on the most advanced version of the Black Hawk in a few years. The gearboxes bolt right into the Hawk family.
Is not one of the "regular" mil-spec rules 30-minute run-dry time? The Canadian military certainly won't accept the CH-148 without this.
FYI, you also get a main transmission that ran 3 hours after a massive oil leak, damage tolerant rotor and structural components, full bird strike protection (controls and drive shaft covers that are nearly ballistic so birds don't cave them in at Vne), and tolerance of engine burst events. {You also get ballistic tolerance, based on the H-60 design requirements, but one hopes this is not necessary in the oil patch!}
I'm assuming reference to the simulated oil cooler leak and bypass switch mode. No mention of what happens when the MRGB is run dry though...
With the S-92, we applied for a certification basis in the FUTURE to capture the draft regulations. This meant that we reached ahead to capture those safety aspects.
Similarly, the S-92 is the only large helicopter to apply for JAR certification, and will shortly work with the JAR test community to get that done.
JAA didn't like the work-around the 30-minute run-dry time requirement, so why was this not looked into more detail e.g. closer analysis of MRGB temperature? IMO nobody appears to have looked at the 11 minute data, instead looked at the 3-hour data. Was it made available to JAA via the FAA?
Your comments are quite valid if one carries the old philosophy of needing to have the pilot stay as a gauge-tender, with one eye on the limit and the other on the rest of the world, but we designed the system to free you of that workload
Well then why did the MRGB temperature gauge get missed off that list?
The oil system of the S-92 is virtually identical to the Black Hawk, and probably the 225. It is dual in every way, as are the indications. The pilots in this emergency landed with an aircraft that could have been flown for hunderds of hours, yet you have purposely posted inuendo that ditching was imminent, that fleets are grounded, and that the sky is falling, and now you need to see the oil system so you can pronounce the S-92 still born.
Comment posted after the Norsk Hydro vespel spline failure. So where is the secondary MRGB temperature sensor? Why not have 2 temperature sensors, one on the feed to the MRGB and one on the return line, that way you have dual-redundancy and also can monitor delta-T for an additional condition-based monitoring tool?
All the above quotes were from the same person, namely the S92 program director. As I read it there is a very strong bias here towards not only the S92 but a big push to get this A/C into production and fleets. I wonder why...and what will change now?
Simple, IMO the S92 design errors will have to be fixed or the A/C will be grounded for civilian use and a suitable replacement such as the EC225 procured by the oil companies. That means acceptable vibration levels, noise levels, robust and proven MRGB.
Safe flying
Max