Special Conditions: Sikorsky Aircraft Corporation Model S-92A Helicopter; Use of a Dual-Engine 30-Minute Power Rating

AGENCY:

Federal Aviation Administration (FAA), DOT.

ACTION:

Final special conditions; request for comments.

SUMMARY:

These special conditions are issued for Sikorsky Aircraft Corporation (Sikorsky) Model S-92A helicopters. The S-92A helicopters will have an unusual feature associated with the use of a dual-engine 30-minute power rating. The applicable airworthiness regulations do not contain adequate or appropriate safety standards for use of this power rating. These special conditions contain the additional safety standards that the Administrator considers necessary to ensure that critical functions of systems will be maintained during use of this rating.

DATES:

The effective date of these special conditions is October 16, 2002. Comments must be received on or before December 30, 2002.

ADDRESSES:

Comments on these special conditions should be mailed in duplicate to: Federal Aviation Administration (FAA), Office of the Regional Counsel, Attention: Rules Docket No. SW011, 2601 Meacham Blvd., Room 663, Fort Worth, Texas 76137; or delivered in duplicate to the Office of the Regional Counsel at the above address. Comments must be marked Docket No. SW011. Comments may be inspected in the Rules Docket weekdays, except Federal holidays, between 8:30 a.m. and 4:00 p.m. The Rules Docket for special conditions is maintained at the Federal Aviation Administration, Rotorcraft Directorate, 2601 Meacham Blvd., Room 448, Fort Worth, Texas 76137.

FOR FURTHER INFORMATION CONTACT:

Ed Cuevas, FAA, Rotorcraft Directorate, Rotorcraft Standards, Fort Worth, Texas 76193-0110, telephone (817) 222-5355, fax (817) 222-5961.

SUPPLEMENTARY INFORMATION:

The FAA has determined that notice and opportunity for prior public comment hereon are impracticable because these procedures would significantly delay issuance of the approval design and thus delivery of the affected helicopter. The FAA therefore finds that good cause exists for making these special conditions effective upon issuance.

Comments Invited

The FAA invites interested persons to participate in this rulemaking by submitting written comments, views, or data. Communications should identify the regulatory docket and be submitted in duplicate to the address specified above. We will consider all comments we receive on or before the closing date for comments. We may change these special conditions in light of the comments we receive. All comments received will be available in the Rules Docket for examination by interested persons, both before and after the closing date for comments. A report summarizing each substantive public contact with FAA personnel concerning this rulemaking will be filed in the docket. If you want the FAA to acknowledge receipt of your comments on this proposal, include a self-addressed, stamped postcard on which the docket number appears. We will stamp the date on the postcard and mail it back to you.

Background

For the Model S-92A helicopter, Sikorsky Aircraft Corporation has applied for use of a dual-engine 30-minute power rating in addition to a maximum continuous power rating. The Sikorsky Model S-92A is a transport category A and B rotorcraft, powered by two General Electric CT7-8 engines certificated with a dual-engine 30-minute power rating greater than the maximum continuous power rating. The S-92A with the CT7-8 engine installation will have 30-Second One-Engine-Inoperative (OEI), 2-Minute OEI, Continuous OEI, 30-Minute, Takeoff, and Maximum Continuous power ratings.

This unusual dual-engine power capability must be limited to use for hovering operations only for periods not to exceed 30 minutes at any time after takeoff, to allow the rotorcraft to fly extended hover maneuvers while performing search and rescue missions. However, this rating is also suitable for other missions that require increased rotorcraft hovering capability and duration, beyond those that the maximum continuous engine rating allows.

The S-92A has the same engine torque and rotor speed limits for use of aircraft 30-minute power or maximum continuous power ratings. As a result, the FAA has determined that compliance with the structural and drive system requirements of 14 CFR part 29 (part 29) has not been affected by the 30-minute rating application.

The applicable airworthiness requirements do not contain a 30-minute power rating definition and do not contain adequate or appropriate safety standards for the type certification of this unusual engine rating. Due to increased engine N ₁ (gas turbine speed) and T _4.5 (power turbine inlet temperature) limits for this new rating, as compared to the existing continuous rating, airworthiness requirements must be specified for powerplant cooling and operational limitations for this novel or unusual design feature.

Type Certification Basis

Under the provisions of 14 CFR 21.17, Sikorsky Aircraft Corporation must show that the Model S-92A helicopter meets the applicable provisions of the regulations as follows:

• 14 CFR Part 29, Amendment 29-1 through Amendment 29-45, inclusive;
• 14 CFR Part 29, Appendix H, Amendments 36-1 through the amendment effective at the time of certification; and
• Any special conditions, exemptions, and equivalent safety findings deemed necessary.

If the Administrator finds that the applicable airworthiness regulations for part 29 do not contain adequate or appropriate safety standards for the Sikorsky Model S-92A because of a novel or unusual design feature, special conditions are prescribed under the provisions of § 21.16.

In addition to the applicable airworthiness regulations and special conditions, the Sikorsky Model S-92A must comply with the noise certification requirements of 14 CFR part 36, and the FAA must issue a finding of regulatory adequacy pursuant to § 611 of Public Law 92-574, the “Noise Control Act of 1972.”

Special conditions, as appropriate, are defined in § 11.19, and issued in accordance with § 11.38, and become part of the type certification basis in accordance with § 21.17(a)(2).

Special conditions are initially applicable to the model for which they are issued. Should the TC for that model be amended later to include any other model that incorporates the same novel or unusual design feature, or should any other model already included on the same TC be modified to incorporate the same novel or unusual design feature, the special conditions would also apply to the other model under the provisions of § 21.101(a)(1).

Novel or Unusual Design Features

The Sikorsky Model S-92A will incorporate the following novel or unusual design features: A dual-engine 30-minute power rating which will require a special condition for hovering cooling test procedures and powerplant limitations.

Applicability

As discussed above, these special conditions are applicable to the Sikorsky Model S-92A. Should Sikorsky Aircraft Corporation apply at a later date for a change to the TC to include another model incorporating the same novel or unusual design feature, the special conditions would apply to that model as well under the provisions of § 21.101(a)(1).

Conclusion

This action affects only certain novel or unusual design features on one model of helicopter. It is not a rule of general applicability and affects only the applicant who applied to the FAA for approval of these features on the helicopter.

Under standard practice, the effective date of final special conditions would be 30 days after the date of publication in the Federal Register; however, as the certification date for the Sikorsky Model S-92A is imminent, the FAA finds that good cause exists to make these special conditions effective upon issuance.

List of Subjects in 14 CFR Parts 21 and 29

• Aircraft
• Air transportation
• Aviation safety
• Rotorcraft
• Safety

The authority citation for these special conditions is as follows: 42 U.S.C. 7572; 49 U.S.C. 106(g), 40105, 40113, 44701-44702, 44704, 44709, 44711, 44713, 44715, 45303.

The Special Conditions

Accordingly, pursuant to the authority delegated to me by the Administrator, the following special conditions are issued as part of the type certification basis for Sikorsky Model S-92A helicopters.

1. Hovering Cooling Test Procedures

Acceptable hovering cooling provisions must be shown for the following conditions, which replace the requirements of § 29.1049:

(a) At the maximum weight, or at the greatest weight at which the rotorcraft can hover (if less), at sea level, with the power required to hover but not more than 30-minute power, in-ground effect with the maximum tailwind velocity and azimuths requested for approval, until at least 5 minutes after the occurrence of the highest temperature recorded or until the expiration of the 30-minute power application period, whichever occurs first; and,

(b) With 30-minute power, maximum weight, and at the altitude resulting in zero rate of climb for this configuration, until at least 5 minutes after the occurrence of the highest temperature recorded or until the expiration of the 30-minute power application period, whichever occurs first.

2. Powerplant Limitations

In addition to the requirements of § 29.1521 the limitations for rated 30-minute power usage must be established as follows:

Rated 30-Minute Power Operations

The powerplant rated 30-minute power operation must be limited to use for periods not to exceed 30 minutes for hovering operations only and limited by:

(a) The maximum rotational speed which may not be greater than

(i) The maximum value determined by the rotor design; or

(ii) The maximum value shown during the type tests;

(b) The maximum allowable power turbine inlet gas temperature;

(c) The maximum allowable engine and transmission oil temperatures.

(d) The maximum allowable power or torque for each engine, considering the power input limitations of the transmission with all engines operating; and

(e) The maximum allowable power or torque for each engine considering the power input limitations of the transmission with one-engine-inoperative.