TSO-C77b, Gas Turbine Auxiliary Power Units

AGENCY:

Federal Aviation Administration, DOT.

ACTION:

Notice of availability of proposed Technical Standard Order and request for public comment.

SUMMARY:

This notice announces the availability of draft Technical Standard Order (TSO), C77b. This proposed TSO pertains to minimum performance standards that gas turbine auxiliary power units (APUs), commonly used in commercial aircraft, must meet in order to be identified with the proposed TSO marking.

DATES:

Comments must identify the TSO file number and be received on or before May 4, 2000.

ADDRESSES:

Send all comments on the proposed TSO to the Federal Aviation Administration, Attn: Engine and Propeller Standards Staff, ANE-110, Engine and Propeller Directorate, Aircraft Certification Service, 12 New England Executive Park, Burlington, MA, 01803-5299. Comments must identify the TSO file number.

FOR FURTHER INFORMATION CONTACT:

Mr. Mark A. Rumizen, Engine and Propeller Standards Staff, ANE-110, Engine and Propeller Directorate, Federal Aviation Administration, 12 New England Executive Park, Burlington, MA 01803-5299, telephone (781) 238-7113, fax (781) 238-7199.

SUPPLEMENTARY INFORMATION:

Comments Invited

A copy of the draft TSO may be obtained by contacting the person named under FOR FURTHER INFORMATION CONTACT. Interested persons are invited to comment on the proposed TSO, and to submit such written data, views, or arguments as they desire. Commenters must identify the TSO file number, and submit comments to the address specified above. All communications received on or before the closing date for comments will be considered by the Engine and Propeller Directorate, Aircraft Certification Service, before issuance of the final TSO.

Background

The standards of this TSO would apply to all APUs used for any new application submitted after the effective date of this TSO. APUs currently approved under TSO-C77 or TSO-C77a authorization may continue to be manufactured under the provisions of their original approval. However, under § 21.611(b) of the Federal Aviation Regulations, any major design change to an APU previously approved under TSO-C77 or TSO-C77a would require a new authorization under this TSO. The general layout of this document complies with the updated TSO format.

How To Obtain Copies

A copy of the proposed TSO-C77b may be obtained via Internet (http:/www.faa.gov/avr/air/air100/100home.htm) or on request from the office listed under FOR FURTHER INFORMATION CONTACT.