Tragic United Airlines Flight 173: Pilot Fatigue and Situational Awareness

Table of Contents

1. Introduction
2. The Aircraft and Crew
3. The Flight
4. The Landing Gear Issue
5. Troubleshooting the Problem
6. Fuel Quantity and Management
7. The Final Moments
8. Aftermath and Investigation
9. Lessons Learned: Crew Resource Management
10. Conclusion

United Airlines Flight 173: A Tragic Tale of Pilot Fatigue and Loss of Situational Awareness

On December 28th, 1978, United Airlines Flight 173 was scheduled to land in Portland, Oregon, after a cross-country trip from New York. However, disaster struck when the plane was stuck in the air, unable to land. The story of Flight 173 is one that is synonymous with pilot fatigue and how the focus on just one aspect of their situation created a far deadlier one that went undiagnosed.

The Aircraft and Crew

United Airlines Flight 173 was a Douglas DC8 aircraft, a symbol of a long-gone era in aviation. The four-engine, narrow-body jetliner first flew in the late 1950s and was still popular well into the 1970s and 80s. In 1978, Flight 173 was their cross-country service from New York to Portland. The plane made a stopover in Denver, which went off without issue. The DC8 took off again on that late December day for the rest of the trip to Portland, with 181 passengers occupying the cabin, including 6 infants. Up on the Flight Deck were 3 pilots, usual for the DC8.

The Flight

The flight was uneventful up until approach. The pilots first contacted the controllers in Portland at 5:05 pm. The plane had descended from its cruising altitude, down to around 10,000 feet. An Approach Controller gave the flight crew instructions for a visual approach onto Runway 28 at Portland. The pilots even radioed to the tower they could see the airport despite being several miles out from it. Visibility that evening was very good, the clouds clear of cloud and haze.

The Landing Gear Issue

The pilots for landing, obviously wanted to lower the landing gear. A component that secures the right underside landing gear had broken so when the landing gear was lowered, instead of gradually lowering into place, it fell and locked into place quickly. This was noticed by passengers in the cabin as an abnormally loud noise and vibration. The pilots also noticed the rapid descent of the landing gear with them even noticing a yawing effect to the right, perhaps linked to the sudden increase in drag that would have been created following the gear’s sudden shift. This also created an abnormality in how the status of that landing gear was shown to the pilots.

Troubleshooting the Problem

Following the activation of the landing gear lever, the pilots Never got the expected illuminating green landing gear lights as a confirmation the gear was down. According to the captain in a post-accident interview as detailed in the accident report, only the nose landing gear light illuminated green. The possibility of a landing gear failure could have posed a danger to passenger safety. The captain with this information now at HAND, takes the opportunity to troubleshoot the problem and does not go in for a landing just yet.

Fuel Quantity and Management

The DC8 had just over 21 tons of fuel loaded in the tanks when it left Denver, enough for not only the trip to Portland but also an extra one hour and 5 minutes of flying time. This extra fuel came from Federal Regulations mandating an extra 45 minutes of flying time on top of the expected trip. United Airlines also had a policy of carrying an extra 20-minute worth of fuel on top of that. However, the plane was burning into its reserve fuel while the safety of a runway was just a few miles away.

The Final Moments

The plane was nearly 20 miles south of the airport and had only begun flying in a North-easterly direction. From their position, they needed to line up for runway 28 adding extra flying time to make it to the runway. With just 1,300 kilograms of fuel, around 3000 pounds, the Flight Engineer once again highlighted the fuel remaining. Another turn was made towards a North-westerly heading. By 6 pm, the plotted flight data shows the plane heading towards the airport. At this point though, the captain was not satisfied to make an approach, a conversation between the captain and first officer arose about how much time the flight attendants had to prepare the cabin.

Aftermath and Investigation

The investigation put this accident down to a loss of situational awareness by the captain, who he himself was held responsible for. Captain Malburn McBroom soon retired afterwards. Aside from the breaking of that one component in the landing gear, there were no other faults with the plane and the aircraft functioned perfectly. This was an accident that was purely pilot error.

Lessons Learned: Crew Resource Management

The crash of United 173 shares a lot in common with other accidents that had occurred over the years. The distraction of potential landing gear problems echoes that of Eastern Airlines Flight 401, another case of a pilot’s loss of situational awareness. It's accidents like United 173 that became case studies in the development of Pilot Crew Resource Management, known simply as CRM for short. The culture of the cockpit all across the world was prone to a hierarchical structure of command. These days, pilots work in a horizontal and democratic workplace where all pilots are encouraged to engage with one another and even challenge each other if necessary.

Conclusion

The crash of United Airlines Flight 173 was a tragic event that could have been avoided. It serves as a reminder of the importance of situational awareness and the need for effective communication and decision-making in the cockpit. The lessons learned from this accident have helped to Shape the aviation industry and ensure that such a tragedy never happens again.