Event Details
During a telephone interview with the National Transportation Safety Board (NTSB) Investigator-in-Charge, the pilot stated that while landing, the airplane porpoised and then veered left off the runway and onto an intersecting runway. A postaccident examination of the airplane found substantial damage to the firewall. The pilot reported that there were no preimpact mechanical failures or malfunctions with the airframe or engine that would have precluded normal operation.
Weather Information
Data from the automated weather observation station located approximately 14 miles northwest of the airport were reviewed. About 7 minutes before the accident, the wind was reported as 310 degrees true at 8 knots, with wind gusts of 16 knots. The airplane landed on runway 02.
FAA Handbook Discussion on Porpoising
The Federal Aviation Administration's Airplane Flying Handbook (FAA-H-8083-3A, 2004) discusses porpoising during landing. It states that porpoising can occur when a bounced landing is improperly recovered, leading to a series of nose-first contacts with the runway. This is often caused by an improper airplane attitude at touchdown, which may result from inattention, misjudging runway height, mistrimming, or forcing the airplane onto the runway. Ground effect reduces elevator control effectiveness and increases the effort needed to raise the nose; insufficient elevator or stabilator trim can cause a nose-low contact and subsequent porpoise.
Porpoising can also arise from improper airspeed control. If the approach is too fast, the airplane may float, and attempts to force it onto the runway while it still wants to fly can lead to a bounce. A gust of wind, runway bump, or slight control input can send the airplane aloft again. The corrective action for porpoising is similar to that for a bounce and depends on severity. In a very slight porpoise without extreme pitch changes, a follow-up landing can be executed by applying sufficient power to cushion touchdown and smoothly adjusting pitch to the proper attitude.
The NTSB continues to investigate the incident.