Addition of Fowler wing flaps aileron droop system, elevator trim spring and new flap actuation system.

Increase maximum ramp weight to7610 pounds, maximum takeoff weight to 7560 pounds, maximum landing weight is 7200 pounds, maximum zero fuel weight is 6533 pounds.

Fabrication of Panida Doubler.

Fabrication of Panida Doubler.

Replacement of certain Goodrich pneumatic deicer boots

System and Structural Provisions for a Civil Contingency Aircraft -Cessna 421C as defined in Cranfield Aerospace document CAeM/Cessna/1326.

Replacement of certain BF Goodrich pneumatic deicer boots.

Fabrication of Dahlia Doubler.

Application of Stewart Systems synthetic fabric covering system to aircraft fuselage, wings, tail surfaces, control surfaces and related parts.