STC SA1361SO

American Aviation Industries LLC 4550 South El Pomar Road Templeton, California 93465 3

and Part 23 of the Federal Aviation Regulations (See Continuation Sheet Page 3)

A7CE

Cessna

421C

Replace the original reciprocating engines with Pratt & Whitney of Canada PT6A-135 or PT6A-112 turbopropeller engines and related Changes, all in accordance with Riley Aircraft Manufacturing Inc. Drawing List CPDL-1, Revision K, dated February 1, 1996, or later FAA approved revision. If the PT6A-135 engine is installed, the Riley Aircraft Corporation Airplane Flight Manual (AFM) dated August 17, 1982, or later FAA approved revision is a required part of this installation. If the PT6A-112 engine is installed, the Riley Aircraft Corporation Airplane Flight Manual (AFM) No. 1723 dated March 22, 1996, or later FAA approved revision is a required part of this installation.

This approval should not be granted to other aircraft of this model on which other previously approved modifications are incorporated unless it is determined that the relationship between this change and any of those other previously approved modifications will introduce no adverse effect upon the airworthiness of this aircraft. This determination should include consideration of significant changes in weight distribution such as an increase in the fixed disposable weight in the fuselage. This approval does not allow the installation of one PT6A-135 and one PT6A-112 engine in a given aircraft. A copy of this certificate and the appropriate AFM must be maintained as part of the permanent records for the modified aircraft. If the holder agrees to permit another person to use this certificate to alter the product, the holder shall give the other person written evidence of that permission.

April 30, 1980

August 18, 1982

November 28, 1984, June 10, 1986, March 6, 1987, July 19, 2012, April 13, 2017 March 22, 1996

(Signature) Steve Bogucki, Manager Technical and Administrative Support Staff Los Angeles Aircraft Certification Office (Title)

SA1361SO

Model 421 CP Certification Basis August 20, 1983

Revised December 30, 1981 Revised April 30, 1982 Revised August 16, 1982

Part 3 of the Civil Air Regulations dated May 15, 1956, as amended by 3-1 through 3-5 and 3-8, excluding the following portions: Subpart B (3.61 through 3.159) and paragraphs 3.195, 3.196,

3.257, 3.265, 3.311, 3.356 through 3.360, 3.411 through 3.430, 3.433 through 3.438, 3.445, 3.448,

3.449, 3.554 through 3.632, 3.634 through 3.638, 3.655, 3.663, 3.664, 3.666, 3.670 through 3.695,

3.728, 3.744, 3.757 through 3.768, 3.778, 3.791 and 3.792.

Include the following portions of 14 CFR part 23 dated February 1, 1965, as amended by 23-1 through 23-14: 23.21, 23.23, 23.29, 23.31, 23.33, 23.141 through 23.147, 23.153 through 23.207,

23.231 through 23.235, 23.251, 23.253, 23.954, 23.955, 23.973, 23.1301*, 23.1309*, as amended by 23.1 through 23.24, 23.25, 23.45 through 23.77, 23.149, 23.335, 23.361, 23.363, 23.367, 23.371,

23.373, 23.629, 23.729, 23.901, 23.905, 23.907, 23.925 through 23.951, 23.959, 23.961, 23.977,

23.991, 23.994, 23.997, 23.1011 through 23.1045, 23.1091, 23.1093, 23.1103, through 23.1155,

23.1163, through 23.1203, 23.1303(a), (b), (e) (d) through 23.1307, 23.1323, 23.1327, 23.1337 through 23.1367, 23.1385(e), 23.1387(e), 23.1416*, 23.1419, 23.1435, 23.1505, 23.1521, 23.1527,

23.1529, 23.1545 through 23.1559*, 23.1583, 23.1587 as amended by 23-1 through 23-26, 23.903.

Including 14 CFR part 36 dated December 1, 1969, as amended by 36-1 through 36-12 and SFAR dated February 1, 1974, as amended by 27-1 through 27-2.

*As applies to flight into icing conditions.

-END-