Portland-Intl

The pilot arrived at the fixed-base operator on the morning of the accident and requested that his airplane be brought outside and prepared for an immediate departure; this occurred 1 hour 15 minutes before his scheduled departure time. Radar data showed that the airplane departed 23 minutes later. According to air traffic control data, shortly thereafter, the ground and departure controllers contacted the tower controller and asked if the airplane had departed yet; the tower controller responded, "I have no idea. We have zero visibility." Weather conditions about the time of the accident included a 200-ft overcast ceiling with about 1/4-mile visibility. Only five radar targets identified as the accident airplane were captured, and all of the targets were located over airport property. The first three radar targets began about midpoint of the 6,500-ft-long runway, and each of these targets was at an altitude of about 60 ft above ground level (agl). The final two targets showed the airplane in a shallow right turn, consistent with the published departure procedure track, at altitudes of 161 and 261 ft agl, respectively. The final radar target was about 1/2 mile from the accident site. Witnesses reported observing the airplane impact trees in a wings-level, slightly right-wing-down attitude at high speed. Examination of the wreckage revealed no preimpact mechanical malfunctions or anomalies of the airplane. The pilot's personal assistant reported that the pilot had an important meeting that required his attendance on the day of the accident flight. His early arrival to the airport and his request to have the airplane prepared for an immediate departure were actions consistent with self-induced pressure to complete the flight. Due to the poor weather conditions, which were expected to continue or worsen, he likely felt pressure to expedite his departure to ensure he was able to make it to his destination and to attend the meeting. This pressure may have further affected his ability to discern the risk associated with departing in low-visibility and low-ceiling conditions. As noted, the weather conditions were so poor that the local air traffic controller stated that he could not tell whether the airplane had departed. Such weather conditions are highly conducive to the development of spatial disorientation. Further, the altitude profile depicted by the radar data and the airplane's near wings-level attitude and high speed at impact were consistent with the pilot experiencing a form of spatial disorientation known as "somatogravic illusion," in which the pilot errantly perceives the airplane's acceleration as increasing pitch attitude, and efforts to hold the nose down or arrest the perception of increasing pitch attitude can exacerbate the situation. Such an illusion can be especially difficult to overcome because it typically occurs at low altitudes after takeoff, which provides little time for recognition and subsequent corrective inputs, particularly in very low-visibility conditions.

The pilot stated that during takeoff, "after becoming airborne, the airplane quit accelerating and a positive climb rate was not established." He pushed the power lever all the way forward, but did not feel a response from the airplane. Witnesses reported that the airplane became airborne, but failed to gain altitude and struck an antenna array and a fence off the departure end of the runway. The airplane continued across a slough, struck an embankment and came to rest about 900 feet from the departure end of the runway on a golf course located adjacent to the airport. Examination of the airplane revealed no pre-mishap airframe anomalies. Examination of the engine revealed that the compressor and power turbines displayed moderate circular rubbing damage to the blades suggesting engine operation at impact, likely in the low to mid power range. Examination of the airframe and engine revealed no anomalies that would have prevented the engine from producing power prior to impact. The reason for the partial loss of engine power was not determined.

The cockpit voice recorder (CVR) recording indicated that the pilot was unable to start the right engine before takeoff, and elected to attempt takeoff with the right engine inoperative. Witnesses reported that the airplane's nose lifted off about 4,100 feet down the runway and that it then became airborne with its wings rocking, attaining a maximum altitude of 5 to 10 feet above the ground before settling back to the ground, departing the right side of the runway and entering an upright slide for about 1/2 mile. Investigators removed the right engine starter-generator from the engine after the accident and found the starter-generator drive shaft to be fractured. The aircraft has a minimum crew requirement of two, consisting of pilot and copilot; the copilot's seat occupant, a private pilot-rated passenger, did not hold a multiengine rating and thus was not qualified to act as second-in-command of the aircraft.

United Airlines Flight 173, departed New York-JFK on a scheduled flight to Portland International Airport (PDX), with an en route stop at Denver (DEN). The DC-8-61 took off from Denver about 14:47. The planned time en route was 2 hrs 26 min. The planned arrival time at Portland was 17:13. There was 46,700 lb of fuel on board the aircraft when it departed the gate at Denver. This fuel included the Federal Aviation Regulation requirement for fuel to destination plus 45 min and the company contingency fuel of about 20 min. At 17:05, Flight 173 called Portland Approach and advised that its altitude was 10,000 ft and its airspeed was being reduced. Portland responded and told the flight to maintain its heading for a visual approach to runway 28. Flight 173 acknowledged the approach instructions and stated, "...we have the field in sight." At 17:07, Portland Approach instructed the flight to descend and maintain 8,000 ft. Flight 173 acknowledged the instructions and advised that it was "leaving ten." At 17:09, Flight 173 received and acknowledged a clearance to continue its descent to 6,000 ft. When the DC-8 was descending through about 8,000 ft, the first officer, who was flying the aircraft, requested the wing flaps be extended to 15 degrees, then asked that the landing gear be lowered. As the landing gear extended, an unusual sound was heard and the aircraft yawed. At 17:12, Portland Approach requested, "United one seven three heavy, contact the tower, one one eight point seven." The flight responded, "negative, we'll stay with you. We'll stay at five. We'll maintain about a hundred and seventy knots. We got a gear problem. We'll let you know." Portland Approach replied, "United one seventy-three heavy roger, maintain five thousand. Turn left heading two zero zero." The flight acknowledged the instructions. At 17:14, Portland Approach advised, "United one seventy three heavy, turn left heading, one zero zero and I'll just orbit you out there 'til you get your problem." Flight 173 acknowledged the instructions. For the next 23 min, while Portland Approach was vectoring the aircraft in a holding pattern south and east of the airport, the flight crew discussed and accomplished all of the emergency and precautionary actions available to them to assure themselves that all landing gear was locked in the full down position. The second officer checked the visual indicators on top of both wings, which extend above the wing surface when the landing gear is down-and-locked. About 17:38, Flight 173 contacted the United Airlines Systems Line Maintenance Control Center in San Francisco. The captain explained to company dispatch and maintenance personnel the landing gear problem and what the flight crew had done to assure that the landing gear was fully extended. He said they were planning to land in about twenty minutes. About 17:44, the captain and the first flight attendant discussed passenger preparation, crash landing procedures, and evacuation procedures. At 17:46, the first officer asked the flight engineer, "How much fuel we got...?" The flight engineer responded, "Five thousand." About 17:50, the captain asked the flight engineer to "Give us a current card on weight. Figure about another fifteen minutes." The first officer responded, "Fifteen minutes?" To which the captain replied, "Yeah, give us three or four thousand pounds on top of zero fuel weight." The flight engineer then said, "Not enough. Fifteen minutes is gonna really run us low on fuel here." Some calculations were made and at 17:52 the flight engineer talked to Portland and discussed the aircraft's fuel state, the number of persons on board the aircraft, and the emergency landing precautions at the airport. A fuel check at 17:57 learned that there were 1,000 lb in each tank, totalling 4,000 lb of fuel. From 17:57 until 18:00, the captain and the first officer engaged in a conversation which included discussions of giving the flight attendants ample time to prepare for the emergency, cockpit procedures in the event of an evacuation after landing, whether the brakes would have antiskid protection after landing, and the procedures the captain would be using during the approach and landing. At 18:01, the flight engineer reported that the cabin would be ready in "another two or three minutes." At 18:02, the flight engineer advised, "We got about three on the fuel and that's it." The aircraft was then about 5 nmi south of the airport on a southwest heading. Portland Approach then asked Flight 173 for a status report. The first officer replied, "Yeah, we have indication our gear is abnormal. It'll be our intention, in about five minutes, to land on two eight left. We would like the equipment standing by. Our indications are the gear is down and locked. We've got our people prepared for an evacuation in the event that should become necessary." At 18:03 Portland Approach asked that Flight 173 advise them when the approach would begin. The captain responded, "...They've about finished in the cabin. I'd guess about another three, four, five minutes." At this time the aircraft was about 8 nmi south of the airport on a southwesterly heading. At 18:06, the first flight attendant entered the cockpit and reported that they were ready in the passenger cabin. At this time the aircraft was about 17 nmi south of the airport on a southwesterly heading. The captain then said, "Okay. We're going to go in now. We should be landing in about five minutes." Almost simultaneous with this comment, the first officer said, "I think you just lost number four ..." followed immediately by advice to the flight engineer, "... better get some crossfeeds open there or something." At 18:06:46, the first officer told the captain, "We're going to lose an engine..." At 18:06:49, the first officer again stated, "We're losing an engine." Again the captain asked, "Why?" The first officer responded, "Fuel." The captain replied, "Why?" Between 18:06:52 and 18:07:06, the CVR revealed conflicting and confusing conversation between flight crewmembers as to the aircraft's fuel state. At 18:07:06, the first officer said, "It's flamed out." At 18:07:12, the captain called Portland Approach and requested, "...would like clearance for an approach into two eight left, now." The aircraft was about 19 nmi south southwest of the airport and turning left. This was the first request for an approach clearance from Flight 173 since the landing gear problem began. Portland Approach immediately gave the flight vectors for a visual approach to runway 28L. The flight turned toward the vector heading of 010 degrees. At 18:09:21, the captain advised Portland Approach, "United, seven three is going to turn toward the airport and come on in." After confirming Flight 173's intentions, Portland Approach cleared the flight for the visual approach to runway 28L. At 18:10:17, the captain requested that the flight engineer "reset that circuit breaker momentarily. See if we get gear lights." The flight engineer complied with the request. At 18:10:47, the captain requested the flight's distance from the airport. Portland approach responded, "I'd call it eighteen flying miles." At 18:12:42, the captain made another request for distance. Portland Approach responded, "Twelve flying miles." The flight was then cleared to contact Portland tower. At 18:13:21, the flight engineer stated, "We've lost two engines, guys." At 18:13:25, he stated, "We just lost two engines - one and two." At 1813:38, the captain said, They're all going. We can't make Troutdale." The first officer said, "We can't make anything." At 18:13:46, the captain told the first officer, "Okay. Declare a mayday." At 18:13:50, the first officer called Portland International Airport tower and declared, "Portland tower, United one seventy three heavy, Mayday. We're--the engines are flaming out. We're going down. We're not going to be able to make the airport." This was the last radio transmission from Flight 173. About 18:15, the aircraft crashed into a wooded section of a populated area of suburban Portland about 6 nmi east southeast of the airport. There was no fire. The wreckage path was about 1,554 ft long and about 130 ft wide. Two crew members and eight passengers were killed, 34 other occupants were injured.

Shortly after a night takeoff from Portland-Intl Airport, while climbing in foggy conditions, the twin engine aircraft lost height and crashed in an open field, bursting into flames. Four passengers were killed while six other occupants were injured.