Case Analysis Term Paper
United Airlines Flight 173

Embry-Riddle Aeronautical University

SFTY 320

I. Summary
On December 28, 1978, United Airlines flight 173, a McDonnell-Douglas DC-8-61 was a scheduled flight from John F. Kennedy International Airport, New York, to Portland International Airport in Oregon, with an en route stop at Denver, Colorado. When the DC-8 was descending through about 8,000 ft on its way to Portland, 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. Upon request, Portland approach then vectored the aircraft in a holding pattern southeast of the airport. After about an hour and a half of circling southeast of the airfield while the flight crew coped with the landing gear malfunction and prepared the passengers for a possible emergency landing, the captain finally decided to begin the approach to runway 28L. The plane crashed during the approach about 6 nautical miles southeast of the airport in a wooded populated of suburban Portland due to fuel exhaustion. The aircraft was destroyed and thankfully because there was no fuel in the fuel tanks, there was no fire. Of the 181 passengers and 8 crewmembers aboard, 8 passengers, the flight engineer, and a flight attendant were killed and 21 passengers and 2 crewmembers were seriously injured (National Transportation Safety Board, 1979).

II. Problem The problem here is that there was absolutely no use of Crew Resource Management, there was an apparent fear of sternness and assertiveness from the copilot and flight engineer, and a huge lack of communication between crew members, which allowed all of the crew members to become so lost in the landing gear problem, allowing the aircraft fuel tanks to be run dry and the plane to crash in a wooded suburban area. In utilizing the SHELL analysis method, we can find all of the contributing factors and their place of origin in where they relate to the human. The SHELL model can be represented in five distinct ways. The interactions between Liveware-Liveware, Liveware-Environment, Liveware-Hardware and, Liveware-Software. These elements have to be smoothly synchronized in order to have a successful and safe flight, and any deviations from the standard norms may result in a crash or disaster (Perry, 2010). The National Transportation Safety Board concluded that the likely cause of the accident was the failure of the captain to properly monitor the aircraft's fuel state and to properly respond to the low fuel state and the crewmember's warnings regarding the low fuel state, which resulted in fuel exhaustion to all engines (National Transportation Safety Board, 1979). The captain’s inattention resulted from his fixation with a landing gear malfunction and preparations for a possible emergency landing. This is an example of the liveware environment relationship. The environment of the cockpit at the time was very unprofessional, very uncoordinated, confusing, uncomfortable, and intense. The fact that an airline captain of so much experience can become so focused on a landing gear problem to the point of forgetting about how much fuel was left on the plane and consequently crash because of fuel exhaustion makes it clear that the cockpit environment was not professional. The first officer and flight engineer had actually mentioned several times to the captain that the fuel state was becoming dangerous, but he did not heed their warnings. The communication between the crew and the captain during the final evaluation of their fuel should be of concern. The crew’s management of fuel quantity was the biggest problem that caused them to start losing engines. The crew’s inability to work as a team and make a concise decision ultimately caused unneeded casualties. The physical weather environment that day was very nice and clear. The weather had no contributing factors to the cause of this accident as there were clear skies and light winds that day (National Transportation Safety Board, 1979). There are several conflicting elements in the liveware hardware interface. The liveware hardware interface is what initially started the snow ball effect in this accident, as everything followed and developed as a result of the liveware hardware relation. The investigation revealed that when the crew lowered the landing gear, a loud thump was heard. Along with this unusual noise was very irregular vibration and yaw of the aircraft. The right main landing gear retract cylinder assembly had failed due to corrosion, and that allowed the right gear to free fall, and although it was down and locked, the rapid and abnormal free fall of the gear damaged a microswitch so severely that it failed to complete the circuit to the cockpit green light that tells the pilots that gear is down and locked (National Transportation Safety Board, 1979). The unusual indications of loud noise, vibration, yaw, and no green light led the captain to abort the landing, so that they would have time to analyze the problem and prepare the passengers for an emergency landing. While the decision to abort the landing was sensible and practical, the accident occurred because the flight crew became so absorbed with diagnosing the problem that they failed to keep an eye on their fuel state and determine a time when they needed to return to land or risk running out of fuel. The liveware software relation also had discrepancies with negative impacts on the flight. Of course, the biggest discrepancy was that the crew did not follow proper procedures for low fuel levels. Had the captain been properly monitoring the fuel, or at least paid attention to the warnings that his flight engineer was throwing at him, he could have made it back to the airport and if anything done a gear up landing on the runway. When it comes down to choosing between running out of fuel and crash landing in an unknown environment versus landing in a possible gear up configuration on a runway, the correct choice is clear. Another liveware software problem that took place was the fight crew not properly going through faulty landing gear indication procedures. Although the crew did not know, the gear was down and locked. The captain dedicated so much of his time and concentration on the problem of the gear and did not follow standard operating procedures. In hind sight, it has been said that the crew should have been able to figure out if their gear were actually down and locked, had they followed the proper procedures and checklists, potentially avoiding the crash in the woods and saving all the lives that were lost. The liveware liveware interface in this crash is also very apparent. I found some of the most critical factors of the crash to be in the liveware component and this was based on a few things. Initially we have the livewire in which the pilot and the crew are the ever changing factors that affect the outcome of the situation. The crew was well experienced and had no known physical or medical issues that would have contributed to their lack of performance (National Transportation Safety Board, 1979). The Captain appeared to be completely distracted with the landing gear malfunction that he literally lost all of his situational awareness. Another factor that aggravates the situation is the complete lack of CRM at the time resulting from continued efforts by the flight engineer and first officer to bring low fuel state up several times but the Captain neglected to address it and land. By the Captain being distracted with the malfunction and wanting to continue holding to troubleshoot, and the other two crew members not being assertive to effectively communicate their critical state, they all found themselves in the dark as each engine flamed out. This unfortunate situation could have been avoided if CRM was in place. Another minor liveware component that must be addressed is the controller at Portland tower who was on duty at the time. I think that the controller should have been aware of the DC-8’s flight path and that should have thrown up some red flags and caused him to be a bit more concerned about the state of flight 173. Flight 173 flew very irregular patterns as they were trying to fix their gear problem.
III. Significance Of The Problem The fact that a very experienced captain and flight crew of three can become obsessed with a landing gear problem to the point of running out of fuel while circling just a few miles short of the airport screams that this problem must be addressed quickly in order to avoid the same accident from occurring. Human factors analysis and classification system (HFACS) is a extensive human error outline. HFACS allows us to look at the different levels of the parties involved, from the organizational influences down to the acts of the pilots themselves, and find exactly what issues need to resolved before they can slip through the holes of the cheese again (Perezgonzalez, 2011). In looking at the acts of the flight crew, we can see that there were certainly some skill based errors involved. Checklist errors and procedural errors were present as the flight crew did not properly use them to verify the position of the gears. Also proper procedures for a low fuel state were not followed. There was also a breakdown in the visual scan of the flight crew and especially the captain who did not notice that the fuel was almost gone. There were also judgment and decision making errors that took place. Risk assessment during operation was not properly done, resulting in the crash. The crew should have assessed the risk of landing with no gear versus crash landing and chosen the option of a gear up landing as it had less risk in the end. This also relates to the improper prioritization of tasks. Too much priority was placed on the landing gear malfunction and not enough on the fuel state. Necessary action was delayed by the captain when the flight engineer gave warning of the low fuel state. This is also an example of ignoring a caution or warning that was present. The next level of the cheese is the preconditions for unsafe acts. In order to avoid redundancy, I am mainly going to focus on personnel factors, which include crew resource management and personnel readiness. This goes back to training of the flight crew in the area of crew resource management and how a lack of training or lack of motivation may have led to the mishap. While the crew was trying to troubleshoot the gear problem, the captain of flight 173 does take the leadership role, but showed very poor crew and team leadership and cross monitoring performance. He made an effort to properly delegate tasks but did so poorly. Assertiveness was an issue on the part of the flight engineer and the first officer who both were trying to make the captain aware of the low fuel state and seemed to try to imply that they should land but had poor assertiveness when it came to making sure that they landed in time to not flame out, thus also displayed very poor communication of critical information. The captain almost was too confident in that he received warnings of the low fuel state but decided to continue holding for some reason. I think that he was over confident in his abilities as a captain, and was thinking that he would be able to cross feed fuel from more full fuel tanks to less full fuel tanks when actually this did not work. All of these are examples of poor communication, poor coordination, and poor planning which all boil down to very poor crew resource management. Another thing to consider in this case is the possibility pilot fatigue in this case. The crew flew from New York to Colorado with the same day. It is very possible that the lack of adequate rest and being tired played a role in poor judgment by the captain and rest of the crew. In moving up to the next level of cheese, we look at the error of supervision in relation to this case. Supervision was definitely inadequate in this case as the captain had very poor decision making skills and had no one above him to make sure he was making the right calls. This is an example of poor operational leadership. There were also deficiencies in the training and of crews at the time. There was no emphasis on working together as team to overcome any adversity. This is not at the fault of the crew members, but rather the airline as a whole which reflects poor policy. Personality conflicts were also a conflict as the captain of an airline at that time had the mentality that they were untouchable. The captain’s personality seemed to be at conflict with the other crew members. The captain planned and ordered the mission on well beyond its capability. Even with several warnings given to him regarding the danger of not landing soon, he pressed on and seemed to think that he was invincible. Proficiency was an issue here as well as the crew was not proficient in trouble shooting their problem with proficient skill and communication. Risk assessment was not properly carried out by the captain as he authorized an unnecessary hazard of circling for so long with such a low amount of fuel. Personnel and operations management failed to correct the known problems of the lack of using the entire crew as a resource. At the time, crew resource management was not in effect and had a direct contribution to this accident. The highest level of cheese in the HFACS analysis is organizational influences. The upper levels of the organizational influences are examined to figure out the final root cause of the accident. Organizational influences are divided into resource management, organizational climate and organizational processes. When looking into the resource management, we can see that crew resource management training was not in place possibly due to financial limitations of the airline. Costs for training and developing a crew resource management program would have been expensive and a risk for the company, as there is uncertainty of whether or not it will work. The organizational culture at the time of this accident was that the captain was ‘god’ and that whatever he said, no matter what, goes. It was very hard for a first officer or flight engineer to challenge a captain who has the mindset that he cannot be corrected. This was due to the culture that was in place in the airline at the time. When looking at the upper level of the cheese, this is the main problem to be found, which was not only present on flight 173, but also all airline cockpits at that time. The lack of crew resource management was the cause of many previous accidents as well.
III. Development of Alternative Actions Once the problem and the significance of the problem are recognized it is necessary to go through the development of alternative actions. Alternative actions include ways to prevent the reoccurrence of this an accident like this, as well as ways to reduce the consequences of this accident. I believe that the best way to prevent the occurrence of an accident like this from ever taking place again is to develop and implement immediately a crew resource management program that all pilots must go through. This program will teach and train pilots and crew members to have better communication, better decision making, assertiveness, leadership and fellowship, teamwork, task delegation, and management (Helmreich, Merritt, Wilhelm, 1999). All of these elements of CRM were exactly what was lacking in the cockpit of flight 173. The implementation of CRM will have numerous positive impacts on the safety of aviation. This can be done by classroom training, video training, simulator training, and other methods. It was actually this accident that caused United Airlines to create Crew Resource Management training and was adopted by all other US airlines as well as the FAA shortly after (Helmreich, Merritt, Wilhelm, 1999). Another alternative action I have come up with to prevent the reoccurrence of this accident is to give all cockpit crew members PIC authority In the case of a crash being imminent. In this case, the flight engineer and the first officer seemed to have an idea of the low fuel state and seemed to understand the severity of it. I believe that they were afraid of trying to correct the captain who at the time was seen as ‘god’ of the cockpit. I think that had they been given PIC authority in a imminent crash scenario, they may have been able to turn the aircraft toward Portland airport much sooner and potentially saved lives. The downside to the though is it may cause confusion and chaos in the case of who is flying the airplane and who really has the final say. But still, I think that this potential policy could save lives. As far as alternative action for reducing the consequences, I think the first one that I would implement is a better and more obvious visual indication of down and locked gear. Aircraft are always going to have mechanical problem, such as gear position indicators not working. I think that there definitely need to be better indications that can assure crew members of their down and locked position beyond any doubt. Had this been in place and the crew could have known for sure that their gear was down and locked, the decision to land would have been made long before the crash took place. Another alternative action for reducing the consequences would be a system on the controllers radar screen that notifies them of low fuel state aircraft. If the controller had any idea of the condition of flight 173, I think that they would have ordered them to return to the airport in time for a safe landing. This system would assist and possibly prevent many crashes related to low fuel states and fuel exhaustion. The only disadvantage to both of these would be the costs associated with them.

Refrences

National Transportation Safety Board. (1979, June 07).United airlines, inc., mcdonnell- douglas, dc-8-61, n8082u. Retrieved from http://www.ntsb.gov/investigations/reports_aviation .html
Perezgonzalez, J. (2011, November 06). Human factors analysis and classification systems (hfacs). Retrieved from http://aviationknowledge.wikidot.com/aviation:hfacs
Perry, M. (2010, August 21). Shell model. Retrieved from http://aviationknowledge.wikidot .com/aviation
Robert L. Helmreich , Ashleigh C. Merritt & John A. Wilhelm (1999) The Evolution of Crew Resource Management Training in Commercial Aviation, The International Journal of Aviation Psychology, 9:1