Cub Crafters Inc CC18-180 N55PK accident near Anchorage, Alaska

Probable cause

The incorrect installation of the rear flight control stick, resulting in the pilot’s inability to control the pitch attitude, coupled with the pilot’s inadequate control system check before departure, all which resulted in an aerodynamic stall during takeoff.

NTSB analysis

The pilot reported that during takeoff, just after becoming airborne, he was unable to move the flight control stick forward. The airplane started climbing aggressively and the pilot attempted to recover using elevator trim control. The airplane subsequently stalled and began an uncontrolled, nose-down descent toward the runway. During the descent, the pilot was able to level the airplane; however, there was insufficient altitude to recover from the stall. The airplane impacted the runway, resulting in substantial damage to the fuselage and both wing lift struts.

The accident pilot reported that just before departure, he did a control system check, which did not reveal any anomalies.

A postaccident examination revealed that the rear flight control stick was incorrectly installed. The flight control stick was installed in reverse. The curve of the control stick was curved forward, which resulted in the control stick contacting the pilot’s (front) seatback, which limited movement and prevented the control stick from moving full forward.

The investigation did not determine who improperly installed the control stick. However, it was normal practice for the pilots to remove and reinstall the rear seat control stick if they were flying with just cargo in the rear seat area. The pilot reported that he has never removed the control stick and was not trained to do so. Had the pilot been trained on the removal and installation of the control stick, he may have noticed the control stick was installed backwards during his preflight. He also stated that he was not aware that the control stick could be installed incorrectly.

The airplane manufacturers’ supplement dated January 13, 2016, which describes the process and requirements for reinstalling the rear control stick, states in part: “Ensure full range of motion (including trim) is met without the rear stick contacting anything.” Additionally, the supplement must be added to the pilot’s operating handbook and the Federal Aviation Administration approved flight manual when the rear control stick is removed and reinstalled.

Following the accident, the operator issued an agency safety alert to address the correct installation of the rear flight control stick. Additionally, the safety alert highlights the preflight and before takeoff checklists requiring flight control checks to verify the maximum range of travel.

Text from the NTSB. Open the NTSB docket for ANC25LA008 for the full record.