NTSB Preliminary

Report into a rudder structural failure involving a Piper PA-12 Super Cruiser, N3188M, that occurred June 8th, 2020, near Anchorage, Alaska.

Background:

According to the flight instructor, they departed Lake Hood Airport (PALH) and proceeded to Twin Island Lake (about 8 nm northwest of PALH), where upon arrival, they conducted a normal landing. After departing, they climbed to about 500 ft above ground level (agl) before turning a left crosswind traffic pattern leg. While on the left crosswind leg, the airplane yawed abruptly to the right and the private pilot indicated that the controls felt strange. The flight instructor assumed control of the airplane and noticed drastically diminished control about the vertical axis. In addition, a significant downward elevator pressure (forward control yoke) was required. In an effort to aid in directional control the water rudders were deployed. Uncertain that he could make a 180° turn and return to Twin Island Lake due to the poor directional control, he elected to return to PALH where emergency services were available and conducted an uneventful landing.

An initial examination of the rudder revealed that the vertical spar tube separated just above the upper hinge point and the top portion of the rudder folded over the horizontal stabilizer tail brace wires.

Report

On June 8, 2020, about 0945 Alaska daylight time, a float-equipped Piper PA-12 airplane, N3188M, sustained substantial damage when it’s rudder structurally failed in flight about 8 miles north of Anchorage, Alaska. The flight instructor and private pilot receiving instruction were not injured. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 instructional flight.

According to the flight instructor, they departed Lake Hood Airport (PALH) and proceeded to Twin Island Lake (about 8 nm northwest of PALH), where upon arrival, they conducted a normal landing. After departing, they climbed to about 500 ft above ground level (agl) before turning a left crosswind traffic pattern leg. While on the left crosswind leg, the airplane yawed abruptly to the right and the private pilot indicated that the controls felt strange.

The flight instructor assumed control of the airplane and noticed drastically diminished control about the vertical axis. In addition, a significant downward elevator pressure (forward control yoke) was required. In an effort to aid in directional control the water rudders were deployed. Uncertain that he could make a 180° turn and return to Twin Island Lake due to the poor directional control, he elected to return to PALH where emergency services were available and conducted an uneventful landing.

An initial examination of the rudder revealed that the vertical spar tube separated just above the upper hinge point and the top portion of the rudder folded over the horizontal stabilizer tail brace wires.

The rudder has been retained for further examination by the National Transportation Safety Board (NTSB) Materials Laboratory.

Aircraft and Owner/Operator Information

Aircraft Make: Piper

Registration: N3188M

Model/Series: PA 12 No Series

Aircraft Category: Airplane

Operating Certificate(s) Held: None

Meteorological Information and Flight Plan

Conditions at Accident Site: VMC

Condition of Light: Day

Observation Time: 17:53 Local

Lowest Cloud Condition:

Wind Speed/Gusts, Direction: / ,

Lowest Ceiling: Broken / 3000 ft AGL

Visibility: 10 miles

Type of Flight Plan Filed: None

Departure Point: Anchorage, AK

Destination: Anchorage, AK

Wreckage and Impact Information

Crew Injuries: 2 None

Aircraft Damage: Substantial

Aircraft Fire: None

Ground Injuries: N/A

Aircraft Explosion: None

Total Injuries: 2 None

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