N505CRJohn V Rawson Jr SPRINT II · 2013

On May 21, 2014, at 1743 eastern daylight time, an experimental amateur-built Quicksilver Sprint II amphibious airplane, N505CR, was substantially damaged when it collided with terrain following a loss of control while on approach to Princeton Airport (39N), Princeton, New Jersey. The commercial pilot was seriously injured. Visual meteorological conditions prevailed, and no flight plan was filed for the local flight, which departed 39N about 1730. The personal flight was conducted under the provisions of Title 14 Code of Federal Regulations Part 91. In interviews with local authorities, the pilot stated that he and the owner/builder of the airplane had flown the airplane together four times earlier on the day of the accident. During three of the four flights, the accident pilot was manipulating the flight controls, and the owner suggested he take the airplane for a solo flight. . The pilot reported that during his first approach for landing to runway 28, he was "unable to keep the aircraft in a straight line," and that the airplane would only turn left, despite his application of full right aileron and rudder. The airplane completed a 360-degree turn back to final approach at an altitude of about 100 feet above ground level. The pilot stated that the airplane continued in the descending left turn, and subsequently impacted trees and terrain.

The pilot held a commercial pilot certificate with ratings for airplane single engine land and instrument airplane. His most recent Federal Aviation Administration second class medical certificate was issued on July 31, 2013. On June 24, 2014, the pilot reported to the NTSB that he had accrued 1,676 hours of flight experience as of that date, of which one hour was in the accident airplane make and model.

The pilot did not possess a seaplane rating. The owner/builder did not possess a flight instructor certificate.

The airplane was issued an FAA airworthiness certificate on October 24, 2013, and at the time of the accident, had accrued 8.1 hours since that date. Operating limitations for the airplane published November 30, 2013 stipulated that the airplane "must be operated at least 40 hours" in its assigned geographic area, which was within a 25 nautical mile radius of Mountain Airpark (OGE5), Cleveland, Georgia. The limitations further stipulated that during the flight-testing phase, no person was to be carried in the airplane unless that person was essential to the purpose of the flight.

Postaccident examination of the airplane by an FAA aviation safety inspector revealed control continuity from the flight controls to the flight control surfaces. The inspector further stated that proper and corresponding movement of the flight controls and flight control surfaces was confirmed. Both the pilot and owner/builder stated that when they flew the airplane together, there were no deficiencies with the performance and handling of the airplane. The FAA inspector stated that his postaccident examination revealed no mechanical deficiencies with the airplane that would have precluded normal operation.

According to FAA Handbook 8083-23, Seaplane, Skiplane, and Float/Ski Equipped Helicopter Operations Handbook:

In the air, seaplanes fly much like landplanes. The additional weight and drag of the floats decrease the airplane's useful load and performance compared to the same airplane with wheels installed. On many airplanes, directional stability is affected to some extent by the installation of floats. This is caused by the length of the floats and the location of their vertical surface area in relation to the airplane's CG. Because the floats present such a large vertical area ahead of the CG, they may tend to increase any yaw or sideslip. To help restore directional stability, an auxiliary fin is often added to the tail. Less aileron pressure is needed to hold the seaplane in a slip. Holding some rudder pressure may be required to maintain coordination in turns, since the cables and springs for the water rudders may tend to prevent the air rudder from streamlining in a turn."

The handbook further stated, "Many of the most common flying boat designs have the engine and propeller mounted well above the airframe's CG [center of gravity]. This results in some unique handling characteristics. The piloting techniques necessary to fly these airplanes safely are not intuitive and must be learned. Any pilot transitioning to such an airplane is strongly urged to obtain additional training specific to that model of seaplane... Depending on how far the engine is from the airplane's CG, the mass of the engine can have detrimental effects on roll stability. Some seaplanes have the engine mounted within the upper fuselage, while others have engines mounted on a pylon well above the main fuselage. If it is far from the CG, the engine can act like a weight at the end of a lever, and once started in motion it tends to continue in motion."