Special Conditions: Sikorsky Aircraft Corporation, Model S76C; Application of Rated 30-Minute Power

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Parts 21 and 29

[Docket No. SW004; Special Conditions No. 29-004-SC]

Special Conditions: Sikorsky Aircraft Corporation, Model S76C;

Application of Rated 30-Minute Power

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final special conditions; request for comments.

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SUMMARY: These special conditions are issued for the Sikorsky Model

S76C helicopter. This helicopter will have a novel or unusual design

feature associated with a new rated 30-minute power. The applicable

airworthiness regulations do not contain adequate or appropriate safety

standards for this new rated 30-minute power. These special conditions

contain the additional safety standards that the Administrator

considers necessary to establish a level of safety equivalent to that

established by the existing airworthiness standards.

DATES: The effective date of these special conditions is June 17, 1998.

Comments must be received on or before July 17, 1998.

ADDRESSES: Comments on these special conditions may be mailed in

duplicate to: Federal Aviation Administration (FAA), Office of the

Regional Counsel, Attention: Rules Docket No. SW004, 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. SW004. Comments may be inspected in the Rules

Docket weekdays, except Federal holidays, between 7:30 a.m. and 4:00

p.m.

FOR FURTHER INFORMATION CONTACT: Scott Horn, FAA, Rotorcraft

Directorate, Rotorcraft Standards Staff, Fort Worth, Texas 76193-0110,

telephone (817) 222-5125, 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

Interested persons are invited to submit such written data, views,

or arguments as they may desire. Communications should identify the

regulatory docket and be submitted in duplicate to the address

specified above. All communications received on or before the closing

date for comments will be considered. The special conditions may be

changed in light of the comments received. 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. Commenters

wishing the FAA to acknowledge receipt of their comments submitted in

response to this special condition must include a self-addressed,

stamped postcard on which the following statement is made: ``Comments

to Docket No. SW004.'' The postcard will be date stamped and returned

to the commenter.

Background

On November 19, 1997, Sikorsky Aircraft Corporation applied for a

change to Type Certificate (TC) No. H1NE for use of a rated 30-minute

power on the Model S76C helicopter. The Sikorsky Model S76C is a

transport category A and B rotorcraft powered by two Turbomeca Arriel

2S1 engines with a maximum gross weight of 11,700 pounds.

This new rated 30-minute power is intended for periods of use up to

30 minutes at any time after takeoff during a flight performing search

and rescue missions. However, this rating is also suitable for other

missions that require increased rotorcraft hovering capability and

duration than the current ratings allow. The Sikorsky Model S76C

helicopter with the Arriel 2S1 engine installation will have the

following power ratings: 30-second One-Engine-Inoperative (OEI), 2-

minute OEI, Continuous OEI, 30-minute, Takeoff, and Maximum Continuous

ratings.

The current rotorcraft maximum continuous rating is at the same

torque and RPM limits as the proposed 30-minute rating. 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 this new rating application. In addition, all the power parameter

limits and ranges for the 30-minute power coincide with the existing

instrument markings for the takeoff rating. Therefore, these markings,

applied to the new 30-minute power, have been found to comply with the

part 29 requirements.

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 new and

unusual engine rating. Due to increased N1 (gas turbine

speed) and T5 (turbine outlet temperature) limits for this

new rating, as compared to the existing continuous rating,

airworthiness requirements must be developed for powerplant cooling and

operational limitations. Additionally, for use of the 30-minute power

rating, the engine manufacturer has established a new method to

determine the engine overhaul time. The new method accelerates the

engine hours time-in-service when the 30-minute rating is used. For the

Sikorsky Model S76C helicopter, the pilot is required to record the 30-

minute rating usage, since no means of automatically counting or

recording is provided. As a result of the additional workload to the

pilot, the FAA has determined that a two-pilot crew is necessary to

meet the minimum flight crew requirements of part 29.

Type Certification Basis

Under the provisions of 14 CFR 21.101, Sikorsky Aircraft

Corporation must show that the Model S76C helicopter with the Arriel

2S1 engine installation meets the applicable provisions of the

regulations in effect on the date of the application or the applicable

provisions of the regulations as referenced in TC Number H1NE. The

regulations incorporated by reference in the TC are commonly referred

to as the ``original type certification basis.'' The regulations

incorporated by reference in TC Number H1NE are as follows:

Part 29, effective February 1, 1965, plus Amendments 29-1 through

29-11;

[[Page 32973]]

in addition, portions of Amendments 29-12, specifically, Secs. 29.67,

29.71, 29.75, 29.141, 29.173, 29.175, 29.931, 29.1189(a)(2),

29.1555(c)(2), 29 1557(c), and portions of Amendment 29-13,

specifically Sec. 29.965, and Amendment 29-21. In addition, for the

Sikorsky Model S76C (with Arriel 2S1 Engine Configuration): Amendment

29-34 specifically 29.67(a)(1)(i), 29.923(a), (b)(1) and (b)(3),

29.1143(f), 29.1305(a)(24) and (a)(25), 29.1521(i) and (j), and

29.1549(e) and Amendment 36-20 of FAR 36, Appendix H; also Special

Condition No. 96-ASW-16. In addition, the certification basis includes

certain special conditions, exemptions and later amended sections of

the applicable Part that are not relevant to these special conditions.

If the Administrator finds that the applicable airworthiness

regulations for part 29 do not contain adequate or appropriate safety

standards for the Sikorsky Model S76C because of a novel or unusual

design feature, special conditions are prescribed under the provisions

of Sec. 21.16.

In addition to the applicable airworthiness regulations and special

conditions, the Sikorsky Model S76C must comply with the noise

certification requirements of part 36, and the FAA must issue a finding

of regulatory adequacy pursuant to Sec. 611 of Public Law 92-574, the

``Noise Control Act of 1972.''

Special conditions, as appropriate, are issued in accordance with

Sec. 11.49, as required by Secs. 11.28 and 11.29(b), and become part of

the type certification basis in accordance with Sec. 21.101(b)(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 Sec. 21.101(a)(1).

Novel or Unusual Design Features

The Sikorsky Model S76C will incorporate the following novel or

unusual design features: A new rated 30-minute power 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 S76C. 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

Sec. 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 S76C is imminent, the FAA finds that good cause exists to make

these special conditions effective upon issuance. The FAA is requesting

comments to allow interested persons to submit views that may not have

been submitted in response to the prior opportunities for comment

described above.

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:

Authority: 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 S76C helicopters.

1. Section 29.1049 Hovering Cooling Test Procedures

In addition to the requirements of Sec. 29.1049, acceptable

hovering cooling provisions must be shown for the following conditions:

(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 in still

air, 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. Section 29.1521 Powerplant limitations

In addition to the requirements of Sec. 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 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 turbine outlet 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.

Issued in Fort Worth, Texas, on June 5, 1998.

Eric Bries,

Acting Manager, Rotorcraft Directorate, Aircraft Certification Service,

ASW-100.

[FR Doc. 98-16078 Filed 6-16-98; 8:45 am]

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