Pennsylvania

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.

On February 7, 2006, about 2359 eastern standard time, United Parcel Service Company flight 1307, a McDonnell Douglas DC-8-71F, N748UP, landed at its destination airport, Philadelphia International Airport, Philadelphia, Pennsylvania, after a cargo smoke indication in the cockpit. The captain, first officer, and flight engineer evacuated the airplane after landing. The flight crewmembers sustained minor injuries, and the airplane and most of the cargo were destroyed by fire after landing. The scheduled cargo flight was operating under the provisions of 14 Code of Federal Regulations Part 121 on an instrument flight rules flight plan. Night visual conditions prevailed at the time of the accident.

The accident airplane was on an instrument landing system (ILS) approach to land, when witnesses reported seeing it spinning in a nose down, near vertical attitude before it collided with the ground. The accident site was about 3 miles from the approach end of the intended runway. A review of radar data disclosed that the private pilot had difficulty maintaining altitude and airspeed while on final approach, with significant excursions above and below the glidepath, as well as large variations in airspeed. Interviews with other pilots in the area just prior to and after the accident revealed that icing conditions existed in clouds near the airport, although first responders to the accident site indicated that there was no ice on the airplane. Post accident inspection of the airplane, its engine and flight navigation systems, discovered no evidence of preimpact anomalies. An analysis of the airplane's navigation system's light bulbs, suggests that the pilot had selected the GPS mode for the initial approach, but had not switched to the proper instrument approach mode to allow the autopilot to lock onto the ILS.

The airplane was on an instrument landing system (ILS) approach in instrument meteorological conditions. The captain initially stated that the airplane was on the ILS approach with the engine power set at flight idle. About 300 feet above the ground, and 1/4 to 1/2 mile from the threshold, the captain made visual contact with the runway. The captain stated that the left engine then surged, which caused the airplane to yaw right and drift left. At the time, the airplane was in visual conditions, and on glideslope, with the airspeed decreasing through 106 knots. The captain aligned the airplane with the runway and attempted to go-around, but the throttles were difficult to move. The airplane began to stall and the captain lowered the nose. The airplane subsequently struck terrain about 500 feet prior to the runway. After the captain was informed that the engine power should not be at flight idle during the approach, he amended his statement to include the approach power setting at 1,000 lbs. of torque. The co-pilot initially reported that the engine anomaly occurred while at flight idle. However, the co-pilot later amended his statement and reported that the anomaly occurred as power was being reduced toward flight idle, but not at flight idle. Examination of the left engine did not reveal any pre-impact mechanical malfunctions. Examination of the airplane cockpit did not reveal any anomalies with the throttle levers. Review of a flight manual for the make and model accident airplane revealed that during a normal landing, 1,100 lbs of torque should be set prior to turning base leg. The manual further stated to reduce the power levers about 30 feet agl, and initiate a gentle flare. The reported weather at the airport about 5 minutes before the accident included a visibility 3/4 mile in mist, and an overcast ceiling at 100 feet. The reported weather at the airport about 7 minutes after the accident included visibility 1/4 mile in freezing fog and an overcast ceiling at 100 feet. Review of the terminal procedure for the respective ILS approach revealed that the decision height was 200 feet agl, and the required minimum visibility was 1/2 mile.

The pilot first reported that the engine oil temperature had dropped below what he normally observed while en route. When he tired to exercise the left propeller control, and then later tried to feather the left engine, he was unable to change the engine rpm. He then heard a pop from the right engine, and advised air traffic control (ATC), he needed to perform a landing at Bradford. He also reported a double power loss. While being radar vectored for the ILS runway 32 approach, he told ATC he was getting some power back. He was radar vectored inside of the outer marker, and broke out mid-field and high. At the departure end of the runway, he executed a right turn and during the turn, the airplane descended into trees, and a post crash fire destroyed it. A witness reported he heard backfiring when the airplane over flew the runway. When the airplane was examined, the landing gear was found down, and the wing flaps were extended 15 degrees. Neither propeller was feathered. Both engines were test run and performed satisfactorily. The left engine fuel servo was used on the right engine due to impact damage on the right engine fuel servo. The right fuel servo was examined and found to run rich. However, no problems were found that would explain a power loss, prevent the engine from running, or explain the backfiring heard by a witness. Both propellers were examined and found to be satisfactory, with an indication of more power on the left propeller than on the right propeller. The weather observation taken at 1253 included a ceiling of 1,100 feet broken, visibility 1 mile, light snow and mist. The weather observation taken at 1310 included a ceiling of 900 feet broken, visibility 3/4 mile, and light snow and mist. According to the pilot's handbook, the airplane could maintain altitude or climb on one engine, but it required the propeller to be feathered, and the landing gear and wing flaps retracted.

The pilot attempted an ILS approach during night, instrument meteorological conditions. The inbound course was 322 degrees magnetic, and the glideslope outer marker crossing altitude was 3,333 feet msl. The decision altitude was 2,370 feet msl and the airport elevation was 2,143 feet msl. A wreckage path, about 370 feet in length, along a track 320 degrees magnetic, commenced with a tree strike about 300 feet southeast of the outer marker, at an elevation of about 2,200 feet msl. Examination of the airplane revealed no mechanical anomalies.

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.

The Boeing 757 departed Newark Airport at 0847LT on a regular schedule service to San Francisco, carrying 37 passengers and a crew of seven. Few minutes later, the aircraft was hijacked by terrorists who modified the flight path and apparently attempted to fly over Washington DC. At 1030LT, the aircraft crashed in an open field located about 4 km north of Shanksville. The aircraft disintegrated on impact and all 45 occupants were killed. The terrorist attacks of September 11, 2001 are under the jurisdiction of the Federal Bureau of Investigation. The Safety Board provided requested technical assistance to the FBI, and this material generated by the NTSB is under the control of the FBI. The Safety Board does not plan to issue a report or open a public docket.

After takeoff, the pilot reported "an engine problem," but did not elaborate. A witness on the ground saw that the left engine was trailing smoke, but the engine was still operating, and did not sound like it was "missing". When asked by the tower controller if he required assistance, the pilot answered "no". The controller cleared the pilot for left traffic to a landing, and provided the current weather. There were no further transmissions from the pilot. Smoothed radar tracking data revealed that the airplane turned toward a left downwind, and leveled off at 1,400 feet msl (about 1,050 feet agl) and 156 knots. During the next 14 seconds, the airplane descended to 1,100 feet and increased airspeed to 173 knots. Then radar contact was lost. Witnesses observed the airplane variously in a right snap roll and a left wingover, followed by a sharp dive to the ground. The airplane had just undergone maintenance. During maintenance, unused oil was found in the left engine cowling, which the pilot admitted he had previously spilled. Following maintenance, the pilot was observed adding 3 additional quarts of oil to the left engine. The engine oil dipsticks were calibrated on both sides, with each side pertaining to the oil level in a specific engine. The side for the right engine was calibrated to read 1 3/4 quarts lower than the left engine. The airplane's wreckage was fragmented. No evidence of mechanical defect was found, nor was there any evidence of an extreme out-of-trim condition. There was also no evidence of engine failure, detonation, or pre-impact failure. The pilot held an airline transport pilot certificate. He reported 3,210 hours of flight time to the operator, and had recently been cleared to fly the airplane on 14 CFR Part 91 flights. The flight to the maintenance facility was the pilot's first solo flight in the airplane. An autopsy of the pilot revealed the presence of a prostate adenocarcinoma; however, according to his physician, the pilot was unaware of it.

The aircraft experienced an uncontained failure of the high pressure turbine stage 1 disk in the No. 1 engine during a high-power ground run for maintenance. Because of a report of an in-flight loss of oil, US Airways mechanics had replaced a seal on the n°1 engine’s integral drive generator and were performing the high-power engine run to check for any oil leakage. For the maintenance check, the mechanics had taxied the airplane to a remote taxiway on the airport and had performed three runups for which no anomalies were noted. During the fourth excursion to high power, at around 93 percent N1 rpm, there was a loud explosion followed by a fire under the left wing of the airplane. The mechanics shut down the engines, discharged both fire bottles into the No. 1 engine nacelle, and evacuated the airplane. Although both fire bottles were discharged, the fire continued until it was extinguished by airport fire department personnel. The aircraft was damaged beyond repair.