Learjet 25

On approach to Bahías de Huatulco Airport, the crew was unable to lower the landing gear. It was decided to perform a wheels up landing. The aircraft landed on its belly then slid for few dozen metres, veered off runway and came to rest, bursting into flames. All six occupants escaped uninjured but the aircraft was destroyed by fire. Among the passenger was Ulises Ruiz Ortiz, Governor of the State of Oaxaca.

About 5 miles from the destination airport, the flight was cleared by air traffic control to descend from its cruise altitude of 5,000 feet for a visual approach. As the first officer reduced engine power, both engines "quit." The captain attempted to restart both engines without success. He then took control of the airplane, and instructed the first officer to contact air traffic control and advise them that the airplane had experienced a "dual flameout." The captain configured the airplane by extending the landing gear and flaps and subsequently landed the airplane on the runway "hard," resulting in substantial damage to the airframe. Both engines were test run following the accident at full and idle power with no anomalies noted. Examination of the airplane revealed that it was equipped with an aftermarket throttle
quadrant, and that the power lever locking mechanism pins as well as the throttle quadrant idle stops for both engines were worn. The power lever locking mechanism internal springs for both the left and right power levers were worn and broken. Additionally, it was possible to repeatedly move the left engine's power lever directly into cutoff without first releasing its power lever locking mechanism; however, the right engine's power lever could not be moved to the cut off position without first releasing its associated locking mechanism. The right throttle thrust reverser solenoid installed on the airplane was found to be non-functional, but it is not believed that this component contributed to the accident. No explicit inspection or repair instructions were available for the throttle quadrant assembly. Other than the throttle quadrant issues, no other issues were identified with either the engines or airframe that could be contributed to both engines losing power simultaneously.

The crew landed with the landing gear in the retracted position. While the airplane was on the base leg of the traffic pattern, the pilot heard a helicopter pilot make a transmission over the common radio frequency. As he completed the before landing checklist the pilot searched for the helicopter that he heard over the radio. During the landing flare he realized something was amiss and looked down at the instrument panel. He noticed that the landing gear lights were illuminated red. Just prior to contacting the runway surface he reached for the landing gear handle and manipulated it in the down position. The airplane made a smooth touchdown with the landing gear in the retracted position. The pilot stated that he did not make the proper check for the gear extension due to the timing of the helicopter distraction. The pilot reported no preimpact mechanical malfunctions or failures with the airplane or engine, stating that the accident was the result of pilot error.

The airplane collided with a berm following a loss of directional control while landing. The airplane was on a 14 CFR Part 91 positioning flight at the time of the accident. The pilots reported that they encountered what they thought were rough spots on the runway during the takeoff roll. The captain reported that after takeoff, he called for the co-pilot to raise the gear and engage the yaw damper. The crew then noticed an unsafe gear indication for the nose gear. The captain stated they leveled off at 5,000 feet and decreased the airspeed so they could recycled the landing gear. Cycling the landing gear did not resolve the problem. The crew then requested to return to the departure airport for landing. The landing gear was extended and a gear down and locked indication for all three landing gear was observed. The captain stated that on touchdown, the co-pilot extended the spoilers and armed the thrust reversers. He stated that after the nose wheel touched down the airplane made a sharp left turn and traveled off the side of the runway through the grass. The airplane contacted a four-foot high berm prior to coming to a stop on another runway. The captain stated he attempted to taxi the airplane only to discover that they did not have any nose wheel steering. Post accident inspection revealed the seal on the nose gear strut had failed which prevented the nose gear from centering.

The captain and first officer were conducting a CFR Part 135 on-demand charter flight, returning two passengers to the accident airplane's base airport. The multi-destination flight originated from the accident airport, about 16 hours before the accident. On the final leg of the flight, the flight encountered stronger than anticipated headwinds, and the first officer voiced his concern several times about the airplane's remaining fuel. As the flight approached the destination airport, the captain became concerned about having to fly an extended downwind leg, and told the ATCT specialist the flight was low on fuel. The ATCT specialist then cleared the accident airplane for a priority landing. According to cockpit voice recorder (CVR) data, while the crew was attempting to lower the airplane's wing flaps in preparation for landing, they discovered that the flaps would not extend beyond 8 degrees. After the landing gear was lowered, the captain told the first officer, in part: "The gear doors are stuck down.... no hydraulics." The captain told the first officer: "Okay, so we're gonna do, this is gonna be a ref and twenty...All right, probably not going to have any brakes..." According to a ATCT specialist in the control tower, the airplane touched down about midway on the 6001-foot long, dry runway. It continued to the end of the runway, entered the overrun area, struck a chain link fence, crossed a road, and struck a building. During a postaccident interview, the captain reported that during the landing roll the first officer was unable to deploy the airplane's emergency drag chute. He said that neither he nor the first officer attempted to activate the nitrogen-charged emergency brake system. The accident airplane was not equipped with thrust reversers. A postaccident examination of the accident airplane's hydraulic pressure relief valve and hydraulic pressure regulator assembly revealed numerous indentations and small gouges on the exterior portions of both components, consistent with being repeatedly struck with a tool. When the hydraulic pressure relief valve was tested and disassembled, it was discovered that the valve piston was stuck open. The emergency drag chute release handle has two safety latches that must be depressed simultaneously before the parachute will activate. An inspection of the emergency drag chute system and release handle disclosed no pre accident mechanical anomalies.

The cargo flight was cleared for a visual approach to the 5,000-foot long, by 150-foot wide asphalt runway. Based on estimated landing weight of the aircraft, the Vref was estimated at 116 KIAS. Air traffic Control (ATC) radar data revealed that the flight maintained a ground speed above 190 knots on final approach, to include the touchdown zone for runway 13. The first evidence of braking was noted at a point 1,247 feet from the departure end of the runway. Braking signatures on the asphalt as well as off the pavement were consistent with an operational anti-skid system. Witnesses at the airport also observed the airplane flying very fast and touching down long. Both crewmembers, the 4,689-hour captain and the 2,873-hour first officer, were familiar with the airport, and the flight was 20 minutes ahead of its scheduled arrival time. The airplane overran the departure end of runway 13, impacted the airport perimeter fence, proceeded across a roadway, took out another fence, and collided with two trees in a cemetery. The airplane was found to be within weight and balance limits for all phases of the flight. The installed cockpit voice recorder (CVR) was found not to be functional.

Shortly before landing, the crew confirmed that the hydraulic and emergency air pressures were "good", and that the circuit breakers on the "right and left" were in. In addition, the first officer reported "arming one and two." The airplane landed 1,000 - 1,500 feet from the landing threshold of runway 04, which was 7,003 feet in length. The captain utilized aerodynamic braking during part of the landing roll. About 3 seconds after touchdown, the first officer stated, "they're not deployed, they're armed only." About 6 seconds after touchdown, there was an increase in engine rpm. Shortly after that, there was an expletive from the captain. One and a half seconds later, there was another expletive. Slightly less than 2 seconds later, the captain told the first officer to "brake me," and 2.7 seconds after that, stated "emergency brake." About 4 seconds later, there was a "clunk", followed by a decrease in engine rpm 1 second later. Immediately after that, the captain stated, "we're going off the end." The airplane subsequently dropped off an embankment at the end of the runway, impacted and descended through a localizer tower, then impacted the ground and slid across a highway. The airplane had been fitted with a conversion that included thrust reversers. An examination of the wreckage revealed that the thrust reversers were out of the stowed position, but not deployed. The drag chute was also not deployed. Brake calipers were tested with compressed air, and operated normally. Brake disc pads were measured, and found to be within limits. According to an excerpt from the conversion maintenance manual, reverser deployment was hydraulically actuated and electrically controlled. There was also an accumulator which allowed deploy/stow cycling in the event of hydraulic system failure. Interlocks were provided so that the reverser doors could not be deployed until the control panel ARM switch was on, the main throttle levers were in idle position, and the airplane was on the ground with the squat switches engaged. The previous crew reported no mechanical anomalies. Runway elevation rose by approximately 35 feet during the first 2/3 of its length, then decreased until it was 8 feet lower at its departure end. Winds were reported as being from 050 degrees true at 7 knots. At the airplane's projected landing weight, without the use of thrust reversers, the estimated landing distance was about 2,850 feet with the anti-skid operative, and 3,400 feet with the anti-skid inoperative.

A commercial pilot, who observed the airplane during the takeoff attempt, stated that it used "lots" of runway, and that the nose lifted "too early and way too slow." The airplane "struggled" to get in the air, and it appeared tail heavy, with "extreme" pitch, about 45 degrees nose-up. It also appeared that the only thing keeping the nose up was ground effect. The airplane became airborne for "a very short time," then sank to the ground, and veered off the left side of the runway. The nose was "up" the whole time, the airplane never "rolled off on a wing," and the wings never wobbled. The engines were "really loud," like a "shriek," and engine noise was "continuous until impact." Another witness at a different location confirmed the extreme nose high takeoff attitude and the brief time the airplane was airborne. It seemed odd to him that an airplane with that much power used so much runway. A runway inspection revealed no evidence of foreign objects or aircraft debris. Tire tracks from the airplane's main landing gear veered off the left side of the paved surface, at a 20-degree angle, about 3,645 feet from the runway's approach end. They continued for about 775 feet, then turned back to parallel the runway for another 650 feet, before ending about 50 feet prior to a chain link fence. There was no evidence that the nose wheel was on the ground prior to the fence. The fence, which was about 1,300 feet along the airplane's off-runway ground track and 200 feet to the left of the runway edge stripe, was bent over in the direction of travel. Ground scars began about 150 feet beyond the fence, and the main wreckage came to rest 300 feet beyond the beginning of the ground scars. The first officer advised a witness that he'd be making the takeoff; however, the pilot at the controls during the accident sequence could not be confirmed. When asked prior to the flight if he'd be making a high-performance takeoff, the captain replied that he didn't know. There was no evidence of mechanical malfunction.

On October 26, 2001, at 1930 central daylight time, a Learjet 25B transport category airplane, N715MH, was substantially damaged when both main landing gears collapsed during the landing touchdown at Ciudad Victoria, State of Tamaulipas, in the Republic of Mexico. The captain, first officer, 2 medical attendants, and 2 passengers aboard the airplane were not injured. The airplane was owned and operated by American Jet International of Houston, Texas. The air ambulance flight originated from the Houston Hobby Airport approximately 1800, and made an intermediate stop at the Matamoros Airport (MMMA) to clear Mexican customs. Night visual meteorological prevailed for the flight, for which and instrument flight rules flight plan was filed.