The tow plane pilot reported that, during takeoff for a glider tow, about 20 to 30 feet above ground, the Piper PA-25 lurched forward and pitched nose down.
He pushed the tow line release mechanism forward, but said it did not feel as if the tow line released.
The airplane hit the ground in a nose-low attitude, exited the runway, hit a runway light and runway sign, and ground looped.
The airplane sustained substantial damage to the right wing.
The pilot of the glider being towed reported that, during takeoff, the glider became airborne and abruptly pitched into a steep, nose-high attitude, and he had lost sight of the tow airplane.
He released the tow rope, maintained level flight attitude about 150′ above ground, and landed on the grass adjacent to the runway without further incident.
The glider pilot reported in a follow up telephone conversation that the glider used a center of gravity (CG) hook set up for the glider tow.
The FAA’s Glider Flying Handbook, FAA-H-8083-13A, contains a section titled “CG Hooks” which states: A CG hook, as compared to a nose hook, makes a crosswind takeoff more difficult since the glider can weathervane into the wind more easily. In addition, a CG hook makes the glider more susceptible to kiting on takeoff, especially if the CG is near the aft limit. This can present a serious danger to the towplane during the aerotow.
It also contains a section titled “Aerotow Takeoff Procedures” which states: One of the most dangerous occurrences during aerotow is allowing the glider to fly high above and losing sight of the towplane. The tension on the towline caused by the glider pulls the towplane tail up, lowering its nose. If the glider continues to rise, pulling the towplane tail higher, the tow pilot may not be able to raise the nose. Ultimately, the tow pilot may run out of up elevator authority.
Probable cause: The glider pilot’s failure to maintain pitch during a CG aerotow, which resulted in the loss of control of the tow airplane.
NTSB Identification: GAA18CA222
This April 2018 accident report is provided by the National Transportation Safety Board. Published as an educational tool, it is intended to help pilots learn from the misfortunes of others.
