History of Flight
On September 16, 2009, at 1642 Pacific daylight time, an experimental light-sport airplane, a Quad City Challenger II, N732LS, collided with terrain in a citrus grove during the landing approach to Redlands Municipal Airport, Redlands, California. The pilot was operating under 14 CFR Part 91. The commercial pilot/co-owner and private pilot co-owner passenger were killed. The airplane sustained substantial damage. The local personal flight departed French Valley Airport, Murrieta/Temecula, California, at 1602, with a planned destination of Redlands Municipal Airport. Visual meteorological conditions prevailed; no flight plan was filed.
A witness flying in the traffic pattern at Redlands airport reported hearing a pilot report on the Common Traffic Advisory Frequency (CTAF) that he was approaching the left downwind for runway 26. The witness described the pilot's voice as "shrill" and "excited." The witness noted that the call was unusual because Redlands uses a right-hand traffic pattern for that runway. The witness then landed and taxied east on the adjacent taxiway. He heard a pilot report on CTAF that he was on left base for runway 26. He observed a high-wing "ultralight" airplane at an elevation of about 300-500 feet agl at a position corresponding to left base. He observed the airplane descend at a 45-degree angle behind trees and out of view.
An impact-damaged Garmin GPSMAP 96C global positioning system receiver was recovered. Data extraction revealed the entire flight sequence from French Valley Airport. The airplane climbed to about 2,300 feet msl and proceeded north at altitudes between 2,300 and 3,000 feet, ground speeds between 40 and 75 knots. It entered the left downwind for runway 26 at approximately 2,400 feet (800 feet agl), maintaining 1-mile separation. While on downwind, ground speed varied between 57 and 69 knots; altitude remained constant. The airplane began a left turn to base leg about 1 mile southeast of the arrival end of runway 26. For 42 seconds it maintained about 58 knots while descending to 2,200 feet. The final recorded GPS position was 4 seconds later at 2,151 feet (450 feet agl) and 64.5 knots. The wreckage was located about 300 feet northwest of that position.
Pilot Information
Front Seat Pilot: The 66-year-old commercial pilot held ratings for airplane single-engine land and glider, and a third-class medical certificate issued May 2008 with corrective lenses limitation. His logbook showed 1,020 hours total airplane time since 1961, with 4.1 hours in a Quad City Challenger II, all in the accident airplane. He also had 168.1 hours in gliders over 494 flights between October 1999 and August 2009.
Aft-Seat Pilot: The 36-year-old private pilot held a certificate for airplane single-engine land and a special issuance third-class medical certificate from November 2003 based on diabetes and insulin use, with limitations not valid after August 31, 2004, and not valid outside the United States. His logbook showed 143.5 hours total airplane time since 1991, with 7.5 hours in a Quad City Challenger II, all in the accident airplane.
Aircraft Information
The two-seat tandem, high-wing, pusher-configuration airplane had a primary structure of fabric-covered metal tubing. Its wingspan was 31 feet 6 inches. It had dual aileron, elevator, and rudder controls, and a single set of wheel brake controls on the forward control stick. It was not equipped with a parachute recovery system or side doors.
FAA records indicate the airplane was manufactured in 1991. In July 2006 it was sold to the pilots; on January 20, 2008, it received an experimental light-sport special airworthiness certificate. The pilots reported it was an existing aircraft without a prior airworthiness certificate and had not been operated as an ultralight under 14 CFR 103.1.
Maintenance logbooks showed its first and only condition inspection on July 18, 2009. Prior flight time was not noted, and no other logbooks were recovered. The Rotax 503 two-stroke engine was mounted above and aft of the cockpit with a two-blade composite Warp Drive propeller. The engine data plate was missing.
The mechanic who performed the inspection stated the pilots replaced the original fabric covering with new covering about two months prior. Prior to purchase, the airplane was used for surveying flights in the Salton Sea area.
Meteorological Information
The closest weather station was San Bernardino International Airport, 5.5 miles west. A METAR at 1651 reported: wind from 270 degrees at 9 knots; visibility 10 miles; few clouds at 11,000 feet; temperature 34°C; dew point 9°C; altimeter 29.88 inches of mercury.
Wreckage and Impact Information
The accident site was in a citrus grove about 1 mile southeast of the arrival end of runway 26. The main structure came to rest at the base of a citrus tree. Surrounding trees were undamaged. The outboard 10-foot section of the right wing was separated and located about 30 feet east. The left wing remained partially attached. The horizontal and vertical stabilizers and control surfaces were co-mingled near the tail. The fuel tank had ruptured but contained about 2 gallons of fuel; fluid was observed in the fuel lines to the carburetors.
Medical and Pathological Information
The San Bernardino County Medical Examiner reported cause of death for both occupants as multiple blunt force injuries. The aft-seat pilot had an insulin pump connected subcutaneously; the pump lacked recording capabilities. A relative stated the pilot was insulin-dependent, compliant with treatment, and diligent about eating and using the pump. Toxicology tests from both pilots showed no carbon monoxide, cyanide, or screened drug substances or alcohol. The vitreous glucose level for the aft-seat pilot was 12 mg/dl; urine glucose was 2470 mg/dl.
Tests and Research
Fuselage and Controls: The forward cabin sustained crush damage. Control cables and push-pull tubes were attached at their mount points but had multiple broomstraw pattern failures. The flap mixer was crushed; the adjustment jack screw was near mid-travel. Elevator push-pull tubes were severed with granular fracture surfaces.
Empennage: No chafing, binding, or fabric separation was noted. Horizontal stabilizer and strut attach points had separated with granular surfaces. Vertical stabilizer spars fractured; internal forward spar surfaces had white and brown deposits consistent with corrosion. No fretting signatures were observed.
Left Wing: Remained partially attached; flaperon attached; most fabric intact.
Right Wing: Outboard 10-foot section separated. Inboard sections partially attached. Fabric covering detached from the leading edge along its length, draped in-trail of the aft spar. Three former ribs failed about 12 inches forward of the trailing edge; fracture surfaces showed necking around rivet holes. The aft spar and flaperon separated about 50 inches from the root with buckling compression signatures consistent with downward bending. The forward spar failed similarly; the inboard forward spar had elongated holes consistent with trailing aft. Wing cable brace separated with broomstraw features. Lift struts buckled with compression signatures. No damage to wing tip or leading edge outboard of spar failures. The inboard aft spar and flaperon had a diagonal scar containing black material consistent with propeller material. The propeller tip had nicks and blue paint transfer marks.
Engine: Examination by NTSB and Rotax representative revealed no catastrophic internal failure or faults precluding operation. The pneumatic fuel pump contained liquid similar to automotive fuel; the pulse diaphragm was intact. The Rotax representative stated the propeller will not windmill after a power loss.
Additional Information: The airplane's weight and balance sheet listed basic empty weight 470 pounds, maximum gross weight 1,010 pounds, and CG range 80–90 inches. Front seat pilot weight was 232 pounds; aft-seat pilot 163 pounds. With 2 gallons of fuel, calculated CG was about 83 inches. A performance card listed Vne (dual) 90 MPH (78 knots), Va (dual) 70 MPH (61 knots), and Vs (dual) 35 MPH (30 knots).
GPS data revealed a prior complete flight on September 3, 2009, from French Valley to Perris Valley Airport, with a similar flight profile. Logbook entries for both pilots corroborated that date.
Construction observations: The tailwheel assembly was affixed with household drywall screws. An automotive paper fuel filter was in line with the fuel tank pickup; the Rotax 503 manual prohibits paper filters. Multiple drilled holes in load-bearing structures did not correspond to plans. Corrosion was noted on the vertical stabilizer attach points, landing gear brake and hub assemblies, and wing strut support structures. Duct tape was used to seal the wing/flaperon gap.
Fabric covering material samples were tested. No manufacturer markings were found. A representative from Consolidated Aircraft Coatings stated the material appeared to be a lightweight uncertified type. Tensile breaking strength tests on six 1-inch-wide strips yielded between 60 and 66 pounds. Similar tests on Poly Fiber uncertified light grade material yielded 60 to 68 pounds. Drain grommets had not been opened. The fabric was affixed with rivets and reinforcement material that appeared to be fiber packaging tape overlaid with painter's masking tape.