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rotormatic
3rd Oct 2004, 14:32
RHL issue with uncertified engine?


On August 30, 2004, approximately 1240 Pacific daylight time, a Sikorsky S-70A twin-engine helicopter, N160LA, experienced an uncontained number 2 engine failure upon reaching cruise flight. The helicopter landed uneventfully with minor damage at the Whiteman Airport, Pacoima, California. The airline transport pilot and two paramedics were not injured. The helicopter was registered to, and operated by, the County of Los Angeles Fire Department (LAFD) as a public-use flight under the provisions of 14 CFR Part 91. The helicopter departed an unimproved landing area approximately 5 minutes prior to the event, and was destined for Palmdale, California. Day visual meteorological conditions prevailed, and a company visual flight rules flight plan had been filed for the flight.

According to the LAFD chief pilot, the helicopter departed on its second flight of the day at an operating weight of 16,900 pounds. It departed the landing area, which was located on top of a mountain at the 3,700-foot level. The observed temperature was 90 degrees Fahrenheit. Upon reaching 100 knots with 80 percent torque, the pilot heard a loud bang followed by a slight yaw variation. The pilot observed that the number 2 engine parameters were indicating a loss of power. The pilot performed the emergency procedures, and diverted to the Whiteman Airport where he performed a run-on landing.

The helicopter's number 2 engine sustained uncontained engine damage at its 8 o'clock position, and the helicopter's titanium firewall was punctured in two locations. One piece of uncontained debris punctured the firewall within 1.5 inches of a fuel line.

The incident helicopter was a civilian version of Sikorsky's Black Hawk helicopter. It utilized two General Electric (GE) T700-701C turboshaft engines, each rated at 1,890 shaft horsepower. The number 2 engine (serial number GE-E-763397) accumulated a total of 1,493 hours, and had not yet undergone an overhaul. According to the LAFD mechanic, the engine was back at the GE service center approximately 100-200 hours prior to the event for an oil leak. The T700-701C engine is not Federal Aviation Administration (FAA) certificated, but shares numerous similarities with the CT-7 engines utilized on the SAAB 340 transport category turboprop airplanes. The engine has been shipped to GE's facility where it will be examined under the supervision of FAA personnel.

Shawn Coyle
4th Oct 2004, 18:39
Sorry - do not understand RHL?
As for 'uncertified' engine - that's why it's not a transport Category Helicopter, but a Utility category.

Cyclic Hotline
5th Oct 2004, 16:51
RHL - Repetitive Heavy Lift
REL - Repetitive External Lift

Sikorsky and GE use RHL and REL cycles in a similar manner as Bell utilises the RIN cycle count. Essentially a means of counting load cycles, to allow for a variable in the flight hour/lift cycle equation formulated on Ground-Air-Ground (GAG) cycles. As most ultimate lives are calculated using straight certification conversions between cycles and flight hours, this essentially takes the calculation in the opposite direction, to ensure the integrity of the component is not compromised.

Typically in RHL/REL operations there is a criteria based upon lifts per hour (or a straight lift cycle count), which is applied to adjust for component ultimate life in order to compensate for high cycle fatigue. In other products utilised in these applications, this has been accomplished and the mandated life limits adjusted accordingly.

I believe the CT7/T-700 was determined to adequately meet the requirements for RHL operation without any life-limit adjustment. Note 13 (http://www.airweb.faa.gov/Regulatory_and_Guidance_Library/rgMakeModel.nsf/0/4f9e7c53f152b24886256a3b005fb8c0/$FILE/h5ne.pdf) of the TCDS refers to life limits, but I don't know the content of that section. With the 214ST now in the firefighting arena, there are two variants of this engine operating in this environment, so maybe this will be reviewed?

Anyone know anything more about this incident? This series engine always seemed to be very good, is anyone aware of any other problems of this nature?



The S-70A (http://www.airweb.faa.gov/Regulatory_and_Guidance_Library/rgMakeModel.nsf/0/4f9e7c53f152b24886256a3b005fb8c0/$FILE/h5ne.pdf) is certified under 21.25(a)(2), as a Restricted Category aircraft. Non Army modifications must comply with Part 29. As a Public Use operator, LA County is free to operate this aircraft in any application they desire.


Sec. 21.25

Issue of type certificate: restricted category aircraft.

[(a) An applicant is entitled to a type certificate for an aircraft in the restricted category for special purpose operations if he shows compliance with the applicable noise requirements of Part 36 of this chapter, and if he shows that no feature or characteristic of the aircraft makes it unsafe when it is operated under the limitations prescribed for its intended use, and that the aircraft--]
(1) Meets the airworthiness requirements of an aircraft category except those requirements that the Administrator finds inappropriate for the special purpose for which the aircraft is to be used; or
(2) Is of a type that has been manufactured in accordance with the requirements of and accepted for use by, an Armed Force of the United States and has been later modified for a special purpose.
(b) For the purposes of this section, "special purpose operations" includes--
(1) Agricultural (spraying, dusting, and seeding, and livestock and predatory animal control);
(2) Forest and wildlife conservation;
(3) Aerial surveying (photography, mapping, and oil and mineral exploration);
(4) Patrolling (pipelines, power lines, and canals);
(5) Weather control (cloud seeding);
(6) Aerial advertising (skywriting, banner towing, airborne signs and public address systems); and
(7) Any other operation specified by the Administrator.

Steve76
5th Oct 2004, 22:00
Will we ever see the Blackhawk outside of the utility catagory?
If not ... why not?

I flew the sim at FSI and was so impressed by the aircraft ergonomics, power and size. It fitted so nicely.

I see it as an aircraft that I could enjoy flying for the remainder of my career as it operates superbly in a number of environments. What a revolution to the civil industry if we could get our hands on a couple of these.

Hedski
6th Oct 2004, 09:32
Didn't Rolls Royce have one at Bristol Filton in UK. G-RRTM I recall. Being civvie registered in UK was it a transport a/c or just for testing? Wouldn't be a bad idea to use such an a/c commercially given its performance. Was witness to a short demo by LCFD a few months ago: WOW!:ok:
Think Autorotate may agree, Ned?

NickLappos
6th Oct 2004, 10:46
The Black Hawk was designed to meet very tough US Army criteria, and does so very aptly, but it has not been FAA certified, and probably will not be. Many detailed design features are done the "Army way" (as we used to say in flight school) and not by FAA/JAA rules.

All Black Hawks that operate do so under the US military flight manual (or the equivilent in the country of registry). The Restricted catagory is provided to allow that.

The engines are approved under US Army/Navy authority, so they are certified, but not to FAR. This is a detail, in fact they are virtually identical to the FAA engines in every way.

Shawn Coyle
6th Oct 2004, 14:01
The RR Blackhawk was used to fit RTM322 engines and was only for testing.
I'm not sure what parts of the S-70 wouldn't meet FARs, and perhaps Uncle Nick could illuminate the confusion here. I'd bet it was in the areas of systems safety, possibly field of view and the like. Performance is indeed wonderful.
And some of the issues about the way it flies and the stuff that's in it is probably out of the control of Sikorsky. 'The Army wanted it that way.'

Steve76
6th Oct 2004, 20:15
So Nick, how many guys could an S70 hold if it was used in a offshore type operation.
Does it have de-ice?

Shawn Coyle
6th Oct 2004, 22:41
The fully civil certified version of the S-70 is probably better known as the S-92....
(Sorry Nick - I know it's not really an S-70, but it's pretty damn close...)