DULUTH, MN, USA
N115CD
Cirrus Design Corp. SR20
The experimental airplane was on a test flight when it impacted terrain following an emergency landing attempt. The airplane was certified as an experimental airplane for crew training. The airplane's aileron spring cartridge and rudder-aileron interconnect had been removed for the test flight. The airplane was loaded with ballast to provide an aft center of gravity with stall tufts attached to both wings. During the test flight, the company test pilot declared an emergency and reported a flight control problem while maneuvering. Radar data indicates that 10 seconds prior to the declaration of an emergency by the test pilot, the aircraft was in a stall phase of flight. Postaccident inspection revealed that the right aileron exhibited evidence of jamming with its wing cove/skin. In postaccident testing of a similar SR20, a manual input pilot force was applied to the side yoke control by a Cirrus Design Corporation (CDC) test pilot. A maximum load of 85 pounds was achieved by the test pilot by leaning forward and applying both hands on the side yoke control. The control input could not be held indefinitely due to muscle fatigue. During the control input, the right aileron was deflected 11 degrees with the left aileron clamped at the inboard rib. CDC test pilots were not graduates of civilian or military flight test schools. The test pilot was not equipped with a personal parachute. A gusting crosswind of approximately 16 knots was present on the selected landing runway. The airplane's maximum demonstrated crosswind component was 19 knots. All runways were available at the time of the accident. CDC was not monitoring radio communications with the accident pilot during the test flight.
HISTORY OF FLIGHT On March 23, 1999, at 1328 central standard time, a Cirrus Design SR20, N115CD, operated by the Cirrus Design Corporation (CDC), was destroyed on impact with terrain following an emergency landing attempt on runway 27 (10,152 feet by 150 feet, dry concrete) at Duluth International Airport (DLH), Duluth, Minnesota. Prior to the landing attempt, the pilot had declared an emergency and reported a flight control problem while maneuvering. Visual meteorological conditions prevailed at the time of the accident. The 14 CFR Part 91 local test flight was not operating on a flight plan. A company test pilot, the sole occupant, was fatally injured. The flight originated from DLH at 1312. At 1312:17, the Duluth Air Traffic Control Tower, Local Control (LC), transmitted, "cirrus one one five charlie delta duluth tower runway two seven you're cleared for take off right turn north bound approved the wind three two zero at one three". The National Transportation Safety Board's (NTSB's) Recorded Radar and Aircraft Performance Study which is included in this report, indicates that N115CD climbed to an altitude of 6,500 feet msl at 1320:27, descended to an altitude of 6,300 feet msl at 1320:51, and returned to an altitude of 6,500 feet msl at 1321:15 which was then followed by a continued descent. At approximately 1322:10, the radar data shows a deceleration of airspeed to 52 knots which was then followed by a continued increase. According to CDC representatives, the typical scenario during stall testing would be to accomplish "aileron maneuvers" to determine hinge moments by first "tracing back and forth" prior to entering the stall series, which would be performed at a minimum altitude of 6,000-6,500 feet. Also, deep stall testing involves aggressively and repeatedly moving the control yoke left and right during the stall to characterize the SR20's deep stall roll stability. At 1322:20, N115CD, transmitted, "---ah tower cirrus one one five charlie delta emergency aircraft about five miles north of the field." Radar data indicates that N115CD was at an approximate altitude of 5,000 feet msl, 167 knots airspeed, and 155 knot ground speed. At 1323:46, N115CD, transmitted, "loud and clear emergency aircraft two miles north of the field flight control problems i'll be turning in bound trying to land on two seven." At 1327:23, N115CD, transmitted, "--- --- cirrus one one five (keyed mike)." There were no additional transmissions by N115CD. In a written statement, the executive vice president of CDC reported the following: "The morning of March 23, after what I believe was the first flight of the day, I had told both flight OPS [operations] and the flight maintenance crew that I wanted the squawks to be taken care of as quickly as possible between flight hops. The first concern that I wanted taken care of was the fact that our ailerons were heavy and that the autopilot could not overcome the friction and turn the airplane, I talked to [the accident pilot] and flight maintenance and had them remove the spring cartridge and the rudder aileron interconnect from the aileron control system. What we were looking for was isolating the problem from an aerodynamic problem or a rigging problem. After lunch I returned at about 12:30 PM and the airplane was outside with [maintenance] going over the logbook with [the accident pilot]. I felt, and believe [the accident pilot] also felt that this was a very routine flight. After [the accident pilot] had taxied away I got into the 182 to go for a short flight around the area. I was taxiing out to runway 27 when [the accident pilot] had flown by. The take off and climb out appeared normal. I took off and flew north over Fish and Island lakes. I was just north of Boulder Lake when I [heard the accident pilot] call and declare [an] emergency. He stated he was five miles north and had a control problem. I turned back to the airport. When [the accident pilot] made his second call I was just north of Rice and he called two miles north. I couldn't see [the accident pilot] but I called him to tell him I was just north of his position if he needed me to come in and take a look at the airplane. He did not answer. The tower did not answer. The tower stated that [the accident pilot] was turning final. I stayed just north of the pattern until the tower stated to the ground units that he had gone down in the prison. I then flew over the prison as the ground safety crew was approaching the sight. I did not see the plane as I flew over. I then circled to land..." A witness reported seeing the airplane overshoot runway 27, track along taxiway A, and enter into a steep bank returning to runway 27. The airplane began tracking over runway 27 at an altitude of 5-15 feet above the runway with its nose yawed approximately 20 degrees to the right. The witness stated the aircraft performed a go-around at the midfield position and made a left 70 degree turn with a bank angle of about 90 degrees, when the airplane's nose sliced down about 20-40 degrees. A second witness located at the U.S. Department of Justice Federal Prison camp, reported the following in a written statement: "On Tuesday, March 23, 1999, at 1:29 pm, I was standing outside the administrative building when I heard a planes engine throttle up to what appeared to be full power. I observed the white plane appear from behind the airport hangers at an approximately 60 degree angle upward. After the plane reached approximately 400-500 feet, the plane leveled his lift and appeared to wobble sideways. The wind appeared to have been a factor and the plane started to bank toward the left. The plane appeared to be maintaining his altitude still in a hard bank to the left, with the engine running at a lower speed. Once the plane appeared to have been over Dorm 211, the planes pitch changed to a steeper decline or nose dive toward the ground, still with the left wing tilting downward. The plane appeared that it would reach the point of impact behind the administrative building or possibly the adjacent parking lot. I immediately began running toward the rear of the building when I lost sight of the plane for approximately 5 seconds. I did not see the point of impact but heard the plane crash into the ground. When I turned the corner of the building, I observed the plane had struck the ground near the Special Housing Unit and slid striking the handicap railing on the walkway leading into the Health Service Unit, then came to rest against the far side of the building..." PERSONNEL INFORMATION The 33 year old pilot was hired by CDC, on June 6, 1996, as the Director of Flight Operations. During his employment at CDC, he served as a flight test pilot during initial and final test phase of the SR20's development and production. The pilot also held an airline transport pilot certificate with a multiengine land rating and a commercial pilot certificate with single engine land and sea ratings. He received a second class medical certificate on July 16, 1998 with no limitations. Federal Aviation Administration (FAA) records indicate that the pilot was involved in a general aviation accident on May 21, 1990 and a general aviation incident on May 20, 1998. He accumulated a total time of 1,311 hours as a United States Air Force Pilot (Air National Guard) and had last flown an F16 on March 19, 1999. CDC reported that the pilot accumulated a total flight time of 741.8 hours in the SR20. No records received indicated the pilot had any formal training as a test pilot. AIRCRAFT INFORMATION N115CD, a CDC SR20, serial number 1001, was a four-place single engine airplane powered by a six-cylinder, 200-horsepower, Teledyne Continental Motors model IO-360-ES(6), serial number 357110, with a three-bladed Hartzell constant speed propeller, serial number JC2A. N115CD was issued an experimental airworthiness certificate for crew training on March 22, 1999. The aircraft had been flown on three flights preceding the accident for a total flight time of 5.1 hours. The total airframe time at the time of the accident was 5.4 hours. The SR20 utilizes conventional flight controls for aileron (roll axis), elevator (pitch axis), and rudder (yaw axis). The control surfaces are pilot-controlled through either of two single-handed side control yokes mounted beneath the instrument panel, and rudder pedals. The control system utilizes a combination of push rods, cables, bell cranks, and spring cartridges for control of the surfaces. Roll trim and pitch trim are available through an electric button on the tip of each "side stick" control yoke; however, the roll trim cartridge which is connected to the roll trim actuator had been disconnected on the accident airplane just prior to the accident flight. A bungee rudder-aileron interconnect is installed in SR20 aircraft to meet FAR (Federal Aviation Regulation) Part 23 certification requirements for lateral stability. The rudder-aileron interconnect provides a minimum of five degrees down aileron with full rudder deflection. Right rudder input will cause right roll input and left rudder input will cause left roll input. With neutral aileron trim, aileron inputs will not cause rudder deflection. The interconnect is a bungee cord that transmits control loads from the aileron cables to the rudder cables after a certain amount of stretch is achieved. The SR20's operating speeds are listed in section 2 of the Pilot's Operating Handbook (POH). The full flap operating range is 56-100 KIAS, the normal operating range is 65-165 KIAS, the caution range is 165-200 KIAS and the never exceed speed (Vne) is 200 KIAS. Weight and balance information for the accident flight was reported by CDC as having a gross weight of 2,900 lbs and a center of gravity of 31.50 inches. The corresponding center of gravity range for a weight range of 2,871-3,045 lbs was 30.19-32.81 inches. The calculations were performed using a pilot weight of 210 lbs, 60 gallons of 100 low lead (100LL) aviation fuel for a fuel weight of 352.2 lbs, and 380 lbs of ballast, which consisted of lead shot. POH Figure 5-8, Wind Components, depicts the wind components versus crosswind component and is included in this report. Using an "angle between wind direction and flight path" of 70 degrees and a wind gust velocity of 17 knots, the corresponding crosswind component is approximately 16 knots. The SR20 POH lists the maximum demonstrated crosswind component for the aircraft as 19 knots. METEOROLOGICAL INFORMATION The DLH automated surface observing system reported, at 1356:26, wind from 340 degrees at 11 knots, gusting 17 knots; 10 statue miles visibility; clear sky conditions; temperature of 2 degrees C and a dewpoint of -8 degrees C; an altimeter setting of 29.91 inches of mercury. AIRPORT INFORMATION DLH is served by runway 09-27 (10,152 feet by 150 feet, grooved concrete) and runway 03-21 (5,699 feet by 150 feet, grooved asphalt). The results of an airport inspection following the accident were reported as clean and dry. WRECKAGE AND IMPACT INFORMATION The airplane impacted an asphalt street within the confines of the U.S. Department of Justice Federal Prison camp located on the southern perimeter of DLH. The coordinates of the main wreckage were: latitude 046 degrees, 50.091 minutes N; longitude 092 degrees, 11.973 minutes W (refer to attachment B of the Airworthiness Group Chairman's Factual Report for a wreckage distribution diagram). No evidence of fire or in-flight structural failure was noted. A white paint scrape mark was found at the northern portion of the wreckage distribution path. The color of the scraping was similar to that of the left wing and belly of the airplane. The scrape mark was approximately 15 inches wide, 31 feet in length, and oriented along a magnetic bearing of 182 degrees. Striations of paint marks were found inside of the scrape mark and were oriented along a magnetic bearing of about 160 degrees. These scrape marks terminated with two slash marks in the asphalt that were about 3/4-inch in depth. The first slash mark was 24 inches in length. The second slash mark was 15 inches in length and began about 15 inches forward, along the wreckage distribution path, from the beginning of the first slash mark. Pieces of propeller blade were found imbedded in a building wall located immediately to the east of the slash marks. The magnetic bearing perpendicular to the slash marks was found to be 170 degrees. Forward of these slash marks was a larger ground scar on the grass that was oriented along a magnetic bearing of 154 degrees. Adjacent to the slash mark, and about 4 feet to the west of it, a gouge was found, followed by rubber marks and primer paint that was consistent with the right main landing gear. Grass scarring was found in this area and ran parallel to a wider area of grass scarring, both of which were oriented along a bearing 154 degrees magnetic. A walkway with black steel railings was found about 75 feet downrange from the curb/grass boundary and was oriented nearly perpendicular to the wreckage distribution path. The steel railings on either side of the walkway were separated from the ground and deformed. The main ground scar ran the entire length of the curb-to-walkway distance. Laying amongst the deformed railing were damaged sections of the outboard right wing. The right aileron and right wing tip were also found in this area. The oil filter, a nose landing gear shock absorption puck, and exhaust tailpipe, and the exhaust attach springs were found near the eastern edge of the walkway (towards the adjacent building) and were embedded in a snowbank. The main body of the airplane wreckage was located about 100 feet to the south of a white paint scraping at the northern edge of the wreckage distribution path. The main body of the airplane wreckage included the engine, cabin area, and empennage. The magnetic bearing of the longitudinal axis, from tail to nose, of the airplane was 163 degrees. The nose gear tire was found about 75 feet further down range where it lay next to a parked automobile that had a shattered windshield and damaged roof. The aircraft engine remained attached to the airframe and was found folded aft and to the left side of the airframe. The linkages for the propeller governor and the mixture control were continuous from the engine to the cockpit. Liquid, consistent with 100LL aviation fuel, was found in the fuel lines leading to the engine-driven fuel pump and in the return lines. A compression check revealed that all six cylinders exhibited compression when the propeller was rotated. The propeller was rotated by hand and engine continuity was established. Oil was found in the engine. Liquid, consistent with 100LL aviation fuel was found in the gascolator. The electrically-driven fuel boost pump was removed by investigators and functionally tested to be operable. Both magnetos were rotated by hand and electrical continuity through the ignition harness was established. The propeller remained attached to the engine. Blade "A", serial number J1826-7, exhibited nicks on its leading edge beginning from the tip and continuing inboard for about 20 inches. Chordwise scratches were also found along the blade, and the outboard portion of the blade was curled forward beginning at a point located about 18 inches inboard of the tip. Blade "B", serial number J1826-6, also exhibited nicks on its leading edge beginning from the tip and continuing inboard about 12 inches. Chordwise scratches were found along the entire span of the blade, and the blade tip was curled forward beginning at a point located about 5 inches inboard of the tip. Blade "C", serial number unknown, separated at a point located approximately 5 inches from the hub and was found with the main wreckage. The separated blade exhibited leading edge gouging and curling. The fuselage was found in one piece, and was severely damaged with disbonding in a majority of the bondlines. The cockpit roof and front windshield were cut away by rescue personnel in order to extract the pilot. The forward floor area was crushed. The left wing was fragmented and the right wing re
the lack of sufficient aileron-to-wing gap clearance design. Contributing factors were the inadequate oversight of the Federal Aviation Administration of the design and manufacturing and flight test process of Cirrus Design Corporation, the location of the control yoke, the inadequate surveillance of the test flight and the test flight procedures by the Cirrus Design Corporation. The destabilizing crosswind condition that existed on the landing runway was an additional factor.
Source: NTSB Aviation Accident Database
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