44 years ago this week, on December 28, 1978, United Airlines Flight 173 crashed in Portland, Oregon killing ten of the 189 passengers and crew. The aircraft involved in the accident was a 10-year-old Douglas DC-8 60 series with the registration N8082U. United Flight 173 was a regularly scheduled flight from John F. Kennedy International Airport (JFK) to Portland International Airport (PDX) with a stop at Denver International Airport (DEN) in Colorado.United Airlines Flight 173 route mapIn charge of the aircraft was 52-year-old Captain Malburn "Buddy" McBroom, assisted by First Officer 45-year-old Roderick "Rod" Beebe and 41-year-old Flight Engineer Forrest "Frosty" Mendenhall. Captain McBroom had worked for United for 27 years and was one of the airline's most experienced pilots. At the time of the crash, he had accumulated 27,600 flying hours, of which 5,500 were on the Douglas DC-8. First Officer Beebe had worked for United for 13 years and had more than 5,500 flying hours. Flight Engineer Mendenhall had been with United for 11 years and, between him and the first officer, had 2,500 flying hours on the Douglas DC-8.

When the plane departed Denver, it had plenty of fuel to get to Portland

After completing the first leg of the journey from New York to Denver, the aircraft took off from Stapleton Airport at 14:47 for the two-hour twenty-six-minute flight to Portland. When the aircraft left the gate in Denver, it had around 46,700 lbs of fuel onboard, and according to the flight plan, they only required 31,900 to get from Denver to Portland.

As the crew approached Portland, they lowered the landing gear and felt an unusual vibration. The indicator light that should have lit up to show that the landing gear had been successfully deployed did not light up, leaving the pilots to worry about the landing. The plane then contacted Portland air traffic control (ATC) to ask permission to perform a holding pattern while they tried to diagnose the problem.

The plane circled over Portland for an hour

For the next hour, the plane circled over southeast Portland as the pilots eventually decided they would need to perform an emergency landing. During the entire time they spent trying to solve the problem, they didn't check how much fuel the plane had left. During the holding pattern, the fuel burn had been exacerbated because the wheels were down, and the plane had its flaps at 15°.

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Photo: Piergiuliano Chesi via Wikimedia Commons.

As a result, as they were landing, the no.3 and no.4 engines flamed out. Lining out to land on Portland's Runway 28L, they lost power to the remaining engines. After declaring a Mayday, the plane crashed into a wooded area six miles southeast of the airport. Of the 189 passengers and crew, the flight engineer and one of the flight attendants, and eight passengers died in the crash. An emergency rescue was launched, and the survivors were quickly taken to local hospitals.

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The investigation and report into the crash of United Airlines Flight 173

While looking into what caused the crash, the National Transportation Safety Board (NTSB) discovered that the right main landing gear was corrupted and fell freely when deployed. The freefall motion caused the vibration when the wheels locked into place. The abrupt fall also damaged a circuit that indicated to the pilots that the gear was down and locked.

In its final report, the NTSB said that the captain had been preoccupied with the landing gear issue as he was thinking about performing an emergency landing. It added this led to neither him nor the other crew members noticing that the plane had exhausted its fuel.