Incident Overview
A student pilot conducting her first solo flight reported that during the second landing, the airplane began to porpoise. On the second bounce, the nose wheel impacted the runway first, resulting in substantial damage to the firewall. The student pilot subsequently taxied the airplane to the tie-down area without further incident.
Pilot Report
According to the student pilot, there were no preimpact mechanical failures or malfunctions with the airframe or engine that would have precluded normal operation.
Background on Porpoising
The Federal Aviation Administration's Airplane Flying Handbook (FAA-H-8083-3A, 2004) discusses porpoising as a phenomenon that can occur during landing. It describes a bounced landing that is improperly recovered, causing a series of motions similar to the jumps and dives of a porpoise. The handbook attributes the issue to improper airplane attitude at touchdown, which may result from inattention, not knowing where the ground is, mistrimming, or forcing the airplane onto the runway.
Additionally, ground effect can reduce elevator control effectiveness and increase the effort required to raise the nose. Insufficient elevator or stabilator trim may lead to a nose-low runway contact, initiating a porpoise. Improper airspeed control is another potential cause: an excessively fast approach can cause the airplane to float, and attempts to force it onto the runway while it still wants to fly can result in bouncing and subsequent porpoising. Gusts of wind, runway bumps, or slight control inputs can also send the airplane aloft again.
The handbook recommends corrective action similar to that for a bounce, depending on severity. For a slight porpoise with no extreme pitch change, a follow-up landing may be executed by applying sufficient power to cushion the touchdown and smoothly adjusting pitch to the proper landing attitude.