Headquarters Office 1933 Dover Road,  Epsom, New Hampshire 03234 Phone:  603-736-4892           Fax: 603-763-3323   Engineering Office 150 High Street,  Canton, Massachusetts 02021-3611 Phone:  781-828-0451            Fax:  781-821-4091

May 3, 1999 (date written)

March 9, 2001 (date revised)

TO: Turbo Products / Northstar Turbine Customers.

Gentlemen:

There are several questions on Turbo Products FAA PMA parts which are asked repeatedly by our customers.

Over the past several years I have prepared written answers to these frequently asked questions. The purpose of this letter is to share those answers with you.

1. Question: "If the Turbo Products parts are not approved by Pratt and Whitney Canada; how do we know they are suitable parts for use in PT6A engines?". Answer: "The Turbo Products FAA PMA parts are approved by the Federal Aviation Administration, United States of America. Attached are copies of the FAA Parts Manufacturer Supplements which are the official FAA documents which approve these parts."

2. Question: "Are these Turbo Products parts as durable as the Pratt and Whitney Canada parts?". Answer: Yes, they are at least as durable and frequently more durable. Attached is a copy of Sermatech's magazine article about a set of, 9,700 flight hours since new, Turbo Products FAA PMA (compressor) turbine blades. After 9,700 flight hours these blades look like they are in new condition.

When I can be of additional assistance, please call me at 781 828 0451, or FAX me at 781 821 4091.

Sincerely,

Ralph Hawkins

Chief Engineer

Northstar Turbine LLC