Accident Overview
On November 19, 2008, about 0740 eastern standard time, a Cirrus Design Corporation SR20, registration N389CP, sustained substantial damage during a forced landing near Reynolds Airpark (FL60) in Green Cove Springs, Florida. The aircraft was operated by CAPT, LLC, doing business as Commercial Airline Pilot Training Program, on a 14 CFR Part 91 instructional local flight from Flagler County Airport (XFL), Palm Coast, Florida. Visual meteorological conditions prevailed, and no flight plan was filed. The certified flight instructor (CFI) and an observer were not injured; the student pilot sustained a minor injury. The flight originated from XFL about 0711.
Flight History
The CFI stated that after takeoff, the intention was to fly to Cecil Field Airport (VQQ) for landing practice. While en route and in contact with Jacksonville Approach Control, the controller advised them to descend at their discretion. The operator reported that the flightcrew reduced throttle for initial descent and was unable to advance it as the flight reached target altitude. The CFI said the student informed him that the throttle was sticking; the CFI attempted to move it but could not. He took controls, maintained best glide airspeed toward FL60, and again tried to advance the throttle unsuccessfully. He advised the controller of the jammed throttle and intended an emergency landing on runway 05 at FL60. While flying toward the runway over a remote wooded area, the airplane contacted tree tops with his hand on the ballistic recovery system handle. The airplane impacted the ground at an estimated 70 knots and nosed over. After coming to rest inverted, neither cabin door could be opened; the rear seat occupant used the emergency egress hammer to knock out the rear window. They evacuated, and the CFI called the operator. Law enforcement initiated a search, and personnel from a fixed base operator at FL60 walked to the airplane and led them out. The student pilot, seated in the left front seat, was taken to a hospital and released the same day.
Aircraft Information
The 2007-manufactured SR20 had accumulated 530.6 hours at the time of the accident. It was equipped with a Cirrus airframe parachute system (CAPS) and AmSafe Airbag Seatbelt (inflatable restraint system) at the pilot and co-pilot seats. The aircraft also had an Avidyne primary flight display (PFD) and multi-function display (MFD), which were retained for further examination.
Examination Findings
Examination of the accident site revealed the airplane came to rest inverted about 222 degrees and 1/4 statute mile from the approach end of runway 05. The airplane was recovered for further examination. Post-recovery examination by the manufacturer and inflatable restraint system manufacturer, with NTSB oversight, showed the airframe parachute system rocket motor propellant was expended and the D-Bag extracted, but the parachute remained packed and the rear harness snubbed; reefing line cutters were not activated and were disposed of. Left forward seat honeycomb was compressed 1/2 inch; right forward seat 1/4 inch. The rear seat pan's forward edge had separated from the forward cross tube at rivets. All seat restraint systems operated correctly post-accident. The pilot and co-pilot inflatable restraint systems showed squaring of the top vent hole.
Engine compartment inspection revealed an electrical cable (alternator output P/N RF 24-30-03 DET) from the No. 2 (standby) alternator was fused against the throttle cable housing (P/N 14392-103). The electrical cable was routed under the throttle cable and exhibited a close radius loop of nearly 180 degrees. A mark was found on a wire bundle protective sleeve of an adel clamp with light contact; two clamping impressions were on the electrical cable exterior. A plastic tie wrap adjacent to the adel clamp was loose. The manufacturer reported that during manufacturing, the electrical cable is not secured by the plastic tie wrap. The clock position of the electrical cable at the alternator differed from its manufacturing position; during manufacture, the cable is routed over the throttle cable with a wide radius loop of nearly 180 degrees.
Discrepancy sheets from the operator showed six entries between April 23, 2008, and November 10, 2008, pertaining to the No. 2 alternator and two entries pertaining to the throttle (October 13 and November 3) indicating the throttle control was tight or difficult to move. Corrective actions for alternator discrepancies included replacing the data acquisition unit (April 25) and master control unit (June 3), which required removal and reinstallation of electrical wires. The throttle control cable was lubricated for both throttle discrepancies. The last 100-hour inspection occurred November 14, 2008. Between April 23 and November 10, the airplane had four 100-hour or annual inspections.
Readout of the PFD and MFD revealed that at approximately 0735 (24 minutes after takeoff), the MFD recorded engine rpm decreasing to 1,500; about 20 seconds later, a sudden increase in Bus No. 2 load amps. The PFD recorded engine rpm continuing to decrease to about 1,240 at ground contact.
Conclusion
The forced landing resulted from a jammed throttle control, which examination indicated was caused by interference from an improperly routed electrical cable from the No. 2 alternator.