Soldotna, AK, USA
N3604A
Piper PA22
In cruise flight, the private pilot heard and felt a “pop” emit from the airplane. He immediately noticed the airplane descending but verified he still had elevator continuity. Unable to maintain altitude, the pilot made an emergency landing on a nearby paved road; however, the airplane landed hard, and the main landing gear collapsed. Postaccident examination revealed control continuity, but it was noted that the adhesive adhering the fabric above the windscreen had separated. FAA Airworthiness Directive (AD) 74-17-04 applies to certain Piper airplanes, including PA-22 series airplanes that are covered with cotton or linen, and was issued to prevent the sudden failure of the material at the top of the windshield by requiring the installation of a reinforcement metal strip. Because the accident airplane was covered in a heavy-duty polyester material, the hardware specified in the AD was not required for installation on the airframe nor was it installed. It is likely that the adhesive adhering the fabric above the windscreen delaminated and disrupted the airflow over the airplane. It was not determined why the adhesive failed/delaminated.
On July 4, 2020, about 1523 Alaska daylight time, a Piper PA-22 airplane, N3604A, was substantially damaged when it was involved in an accident near Soldotna, Alaska. The private pilot was not injured. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 personal flight. The pilot reported that once established in a cruise flight configuration, around 1,300 ft mean sea level (msl), he heard and felt a “pop” emit from the airplane. He immediately noticed the airplane was descending and verified that he still had elevator continuity by looking back at the empennage. The elevator was not “stuck”, but he was unable to maintain altitude. He made an emergency landing on a nearby paved roadway, but during the touchdown, the airplane landed hard and the main landing gear collapsed. The airplane sustained substantial damage to the left wing, both wing struts, and the fuselage. A Federal Aviation Administration (FAA) aviation safety inspector examined the airplane after recovery and reported that the flight control cables were intact, and that flight control continuity was established. The inspector noted that the area above the windscreen where the fabric was connected to the fuselage had separated. He also indicated that the fabric did not tear; rather, the adhesive that held the fabric to the structure delaminated. FAA Airworthiness Directive (AD) 74-17-04, dated April 11, 1977, and applicable to certain Piper airplane models, including PA-22 series airplanes, that are “covered with cotton or linen at the critical area on top of the windshield” where the fabric attaches to the structure was issued to prevent the sudden failure of the material at the top of the windshield by requiring the installation of a reinforcement metal strip. The accident airplane was covered in Ceconite 101, a heavy-duty polyester material. The AD hardware was not installed on the airframe of the accident airplane nor was it required to be.
The delamination of the fabric material from the fuselage above the windscreen due to failed adhesive, which resulted in disrupted airflow and a subsequent hard landing.
Source: NTSB Aviation Accident Database
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