Learjet 35

During the takeoff roll, after the pilot disengaged the nose gear steering, the airplane began to turn to the right. The copilot noticed fluctuations with the engine indications, and called for an abort. Power was reduced to idle, and the pilot corrected to the left using left rudder pedal and braking. The airplane turned to the right again, and the pilot corrected to the left. The airplane continued to turn left, and departed the left side of the runway, tail first, and was substantially damaged. The airplane had accrued 18,040.3 total hours of operation. It was powered by two turbofan engines, each equipped with an electronic fuel computer. Examination of the left engine's wiring harness revealed that the outer shielding on the fuel computer harness assembly was loose, deteriorated, and an approximate 3-inch section was missing. Multiple areas of the outer shielding were also chaffed, the ground wire for the shielding was worn through, and the wiring was exposed. Testing of the wiring to the fuel computer connector, revealed an intermittent connection. After disassembly of the connector, it was discovered that the connector pin's wire was broken off at its crimp location. Examination under a microscope of the interior of the pin, revealed broken wire fragments that displayed evidence of corrosion. Simulation of an intermittent electrical connection resulted in N1 spool fluctuations of 2,000 rpm during engine test cell runs. According to the airplane's wiring maintenance manual, a visual inspection of all electrical wiring in the nacelle to check for security, clamping, routing, clearance, and general condition was to be conducted every 300 hours or 12 calendar months. Additionally, all wire harness shield overbraids and shield terminations were required to be inspected for security and general condition every 300 hours or 12 calendar months, and at every 600 hours or 24 calendar months. According to company maintenance records, the wiring had been inspected 6 days prior to the accident.

The aircraft was flying back to Paraná (Argentina) with an intermediate stop at Santa Cruz with 3 military personnel and 3 technicians and board. They came in La Paz to deliver humanitarian aids after important flood in Bolivia. Shortly after takeoff, while in initial climb, the aircraft entered an uncontrolled descent and crashed in an open field located 20 km from La Paz-El Alto Airport. All six occupants were killed.

The airplane collided with the ground during a low altitude, steep banked, base-to-final left turn toward the landing runway during a circling instrument approach. The airplane impacted terrain 1/3-mile from the approach end of runway 28, and north of its extended centerline. A witness, located in the airport's administration building, made the following statement regarding his observations: "I saw the aircraft in and out of the clouds in a close base for [runway] 28. I then saw the aircraft emerge from a cloud in a base to final turn [and] it appeared to be approximately 300-400 feet above the ground. The left wing was down nearly 90 degrees. The aircraft appeared north of the [runway 28] centerline. The aircraft pitched nose down approximately 30-40 degrees and appeared to do a 1/2 cartwheel on the ground before exploding." ATC controllers had cleared the airplane to perform a GPS-A (circling) approach. The published weather minimums for category C and D airplanes at the 5,900-foot mean sea level airport was 3 miles visibility, and the minimum descent altitude was 8,200 feet mean sea level (msl). Airport weather observers noted that when the accident occurred, the visibility was between 1 1/2 and 5 miles. Scattered clouds existed at 1,200 feet above ground level (7,100 feet msl), a broken ceiling existed at 1,500 feet agl (7,400 feet msl) and an overcast condition existed at 2,400 feet agl (8,300 feet msl). During the approach, the first officer acknowledged to the controller that he had received the airport's weather. The airplane overflew the airport in a southerly direction, turned east, and entered a left downwind pattern toward runway 28. A 20- to 30-knot gusty surface wind existed from 220 degrees, and the pilot inadequately compensated for the wind during his base leg-to-final approach turning maneuver. The airplane was equipped with Digital Electronic Engine Controls (DEEC) that recorded specific data bits relating to, for example, engine speed, power lever position and time. During the last 4 seconds of recorded data (flight), both of the power levers were positioned from a mid range point to apply takeoff power, and the engines responded accordingly. No evidence was found of any preimpact mechanical malfunction. The operator's flight training program emphasized that during approaches consideration of wind drift is essential, and a circling approach should not be attempted in marginal conditions.

A witness saw the airplane approach from the east. She said that the airplane came in "pretty fast" and touched down "approximately half way down the runway." The witness said, "The nose was down. He hit the ground and within 3 seconds he was off the runway and gone. Then all you saw was smoke." The witness said when the airplane hit "the front end shook. It wobbled like a kid on a tricycle. When it shook, it kind of looked like it [the airplane] bounced. Then it was gone." The control tower operator said he heard the captain say something over the radio, which caused him to look in the direction of the airplane. The tower operator saw the airplane off the runway, the main landing gear came off behind the airplane, and the airplane caught fire. The tower operator said he saw four people get out of the airplane. The airplane came to rest in a shallow ravine approximately 331 feet north of the runway. An examination of the airplane showed impact damage to the nose gear and nose gear wheel well. An examination of the airplane's systems revealed no anomalies.

The Learjet 35A received substantial damage on impact with airport property and terrain during a landing overrun on runway 19 (7,002 feet by 150 feet, grooved asphalt) at Charles B. Wheeler Downtown Airport (MKC), Kansas City, Missouri. The airplane was operated by a commercial operator as a positioning flight to Kansas City International Airport (MCI), Kansas City, Missouri, with a filed alternate destination of Lincoln Airport (LNK), Lincoln, Nebraska. Night instrument meteorological conditions prevailed at the time of the accident. LNK was a certificated airport with a snow removal plan and was served by runway 17R (12,901 feet by 200 feet, grooved asphalt and concrete). The flight was en route to MCI to pick up passengers and continue on as an on-demand charter but diverted to MKC following the closure of MCI. MCI was closed due to a McDonnell Douglas MD83 sliding off a taxiway during an after landing taxi on contaminated runway/taxiway conditions. MKC held a limited airport certificate that did not have a snow removal plan and was served by runway 19. Following a precision approach and landing on runway 19 at MKC, the Learjet 35A slid off the departure end of the runway and impacted airport property and terrain. The Learjet 35A was operated with inoperative thrust reversers as per the airplane's minimum equipment list at the time of the accident. About 1:05 hours before the accident, runway 19 Tapley values were recorded as 21-22-22 with 1/2 inch of wet snow. About 17 minutes before the accident, MKC began snow removal operations. About 7 minutes before the accident, the MKC air traffic control tower (TWR) instructed the snow removal vehicles to clear the runway for inbound traffic. TWR was advised by airport personnel that runway 19 was plowed and surface conditions were 1/4 inch of snow of snow; friction values were not taken or reported. While inbound, the Learjet 35A requested any braking action reports from TWR. The first airplane to land was a Cessna 210 Centurion, and the pilot reported braking action to the TWR as "moderate", which was then transmitted by TWR as "fair" from a Centurion in response to the Learjet 35A's query. The Cessna 210 Centurion pilot did not use brakes during landing and did not indicate this to TWR during his braking action report. The Aeronautical Information Manual states that no correlation has been established between MU values and the descriptive terms "good," fair," and "nil" used in braking action reports. The Airport Winter Safety and Operations advisory circular (AC) states that "pilot braking action reports oftentimes have been found to vary significantly, even when reported on the same frozen contaminant surface conditions." The AC also states, "It is generally accepted that friction surveys will be reliable as long as the depth of snow does not exceed 1 inch (2.5 cm) and/or depth of wet snow/slush does not exceed 1/8 inch (3mm). The Learjet 35A flightcrew calculated a landing distance 5,400 feet. Two of the cockpit voice recording channels, which normally contain the pilot and copilot audio panel information, were blank.

On October 24, 2004, about 0025 Pacific daylight time, a Learjet 35A twin-turbofan airplane, N30DK, registered to and operated by Med Flight Air Ambulance, Inc. (MFAA), collided into mountainous terrain shortly after takeoff from Brown Field Municipal Airport (SDM), near San Diego, California. The captain, the copilot, and the three medical crewmembers received fatal injuries, and the airplane was destroyed. The repositioning flight was operated under the provisions of 14 Code of Federal Regulations (CFR) Part 91 with an instrument flight rules (IFR) flight plan filed. Night visual meteorological conditions prevailed. The flight, which was the fourth and final leg of a trip that originated the previous day, departed SDM at 0023.