Lee Campbell Flight 811 Investigation
Anthony Vallido
Aviation Safety 409 Abstract United Airlines Flight 811 left Honolulu bound for Auckland, New Zealand on February 24, 1989. A few minutes in the flight the cargo doors blew out and because of the decompression, nine passengers were immediately sucked out of the plane. The debris from the cargo door damaged the planes Number 3 and 4 engines. Captain David Cronin prepared for an emergency landing. The parents of one of the fatalities, Lee Campbell, investigated the accident because they want to know what caused the cargo door to open in midair. Kevin and Susan Campbell were very persistent and relentless in their fight to prove that the cause of the cargo door opening is a malfunction in the electrical system of the locking mechanism. It would take them a few years and spend their own money just to prove their theory and prevent future accidents from happening. Their persistence paid off when the NTSB finally issued a report stating what the Campbell’s have been campaigning all along.

Introduction On February 24, 1989, United Airlines Flight 811 took off from Honolulu bound for New Zealand. The flight carried 337 passengers, 3 flight crew and 15 flight attendants. The pilots were Captain David Cronin, First Officer Al Slader and Flight Engineer Mark Thomas. After the plane has been in the air for16 minutes, the passengers heard a grinding sound followed by a loud thud which shook the aircraft. A few seconds later the cargo door blew out and the passengers right beside it were immediately ejected out of the airplane. One of the passengers was Lee Campbell. Engines number 3 and 4 were severely damaged from the debris that came from the cargo door that blew off. The debris also damaged the planes right wing LED (Leading Edge Devices) and dented the horizontal stabilizers on that side. Captain Cronin ordered Flight Engineer Thomas to tell the crew to prepare for emergency landing, however he was not able to contact the crew. He then proceeded to go down to check what was happening. When he got down, he saw the extent of the damage to the aircraft. Immediately after leaving the cockpit, he saw that the skin was peeled off in some areas of the deck revealing the frames and stringers. As he went down to the lower deck, he saw the huge hole at the side of the plane and realized the magnitude of the damage. Thomas returned to the cockpit visibly shaken and reported the damage that he saw. At this point he suspected that it was probably a bomb and suggested that they not go over a speed of 250 knots. With limited information, Captain Cronin was able to land the plane without going off the runway. When the plane came to a halt, all passengers and crew were evacuated in 45 seconds. Some of the flight attendants suffered some injuries. The question here is what caused the cargo doors to open? Was it human error or was it electrical in nature?
Investigation
Lee Campbell was one of the casualties of Flight 811. He was returning home to New Zealand when the accident happened. His parents Kevin and Susan Campbell started an independent investigation from the NTSB. The initial investigation placed the blame on Brian Kitaoka, who at that time worked as a Ramp Serviceman for United Airlines. However, Kevin and Susan Campbell were not satisfied with this cause, which is human error, and continued to pursue their investigation. It took a long time for them to finish the investigation because they could not find the door of the plane. Without that door, they will not be able to check it for electrical errors. They eventually found the door 18 months later, 5km on the ocean floor.
The Campbell’s embarked on a relentless personal investigation. Kevin said you can’t let the death of Lee be for nothing. Two months after the crash when the NTSB held preliminary hearings, the Campbell’s made sure they were there. They soon get frustrated because the NTSB will not complete their investigation for months. That is when they decided to take matters into their own hands. Kevin and Susan decided to get the documents from the NTSB during the hearing without permission. From these documents they found information that was not released to the public. There were reports that there disturbing problems with the forward cargo door going right back to its original design. Instead of a plug door that gets jammed into its frame as the aircraft pressure rises, Boeing opted for an outward opening door which allows for more cargo space but the door is not failsafe like the plug design so Boeing built was they thought was a fool proof locking mechanism. Boeing built in multiple redundancies to make sure the door is properly latched and does not open. They built it to a point where it is extremely improbable for the door to open. The Campbell’s discovered that the problem lies with the locking mechanism. To lock the cargo door on the 747, electric motors rotate C-shaped latches around pins in the door frame. A handle then moves L-shaped arms known as locking sectors over the top of the C-shaped latches to prevent them opening. But as early as 1975, problems were found with the locking sectors. Kevin Campbell, an experienced engineer, built a model to show the weakness of the Boeing design. Initially the locking mechanisms were made of aluminum and in 1975 they did not realize that it was not strong enough. The weakness of the aluminum drastically increased the risk of the door accidentally opening. With the aluminum locking sectors, if the C locks tried to backwind open electrically, it would push the locking sector out of the way. It was not doing what it was supposed to be designed for. For twenty years before the accident of Flight 811, 747’s have been flying with this crucial weakness. The Campbell’s wondered what is left to be revealed. They redoubled their efforts to uncover the full truth behind the accident that killed their son. They went to the US to talk to as many people as they can who was involved in the accident. They started at Seattle then went to Chicago all the way to Washington DC then on to San Diego. The Campbell’s soon found out that a shockingly similar incident to Flight 811 had given clear warning of the dangers of the cargo door. In 1987, two years before Flight 811 a Pan Am 747 had been climbing out of Heathrow when it failed to pressurize at 20,000 ft. The pilots had to turn back. When they got to Heathrow, they found out that the door had been hanging open an inch and a half at the bottom and all of the locks were open. When it got to the maintenance base they found that all the locking mechanisms were either bent or broken.

Locking Mechanism Flaw Why had the C-latches turned and bent back the locking sectors? Boeing claimed that ground crew must have mishandled mechanism. But the Campbell’s investigation uncovered another vital clue as to why the C-latches had turned. A report by Pan Am engineers highlighted problems with the doors electrical system. It had a problem with the S2 master lock switch that should’ve turned off the power to the door when the outer handle was closed. This was an alarming finding. When the outer handle was closed the S2 master lock switch was meant to disconnect the power supply and stop the C-latch motors from turning. So could this have failed allowing the motors to open the door? To find out, Boeing asked the airlines to do a simple test. Close the outer handle then press the switch to open the door and see what happens. When they hit the switch, it actually worked. Boeing thought that it wouldn’t work but it did. There was power to the door locks with the outer handle closed and locks started to move and started to force the locking sectors out of the way. A few days later the airlines started calling saying that it was damaging their planes so Boeing stopped the test. This meant that on those aircrafts the S2 locking mechanism had failed and those aircrafts has the potential of having the same problem as Flight 811. It would just take a short circuit to open the doors in mid flight.

The Campbell’s now became convinced that the accident on Flight 811 began with a failure of the S2 switch. Power remained on the C latch motors. All it took was a short circuit on the 20 year old wiring which had been found to be frayed on other aircraft to start the motors up. The aluminum locking sectors were too weak to stop the latches turning and the cargo door burst open. After a year of investigation the NTSB had a different version of the events. The Campbell’s were in for a shock. After waiting for a year, the Campbell’s expected the findings to match their theory on what happened. They assumed that the report will come out and that it would state that it was a malfunction but were surprised when it was reported that the door had been mishandled. For the Campbell’s, the NTSBs flawed explanation and failure to mention the electrical problems just wasn’t good enough. They went back to investigating the accident and soon found disturbing evidence of how it could and should have been prevented.
Resolving the Problem After the Pan Am incident in 1987, it turned out that Boeing had issued a directive to the airlines on how to correct the weak aluminum locking sectors. The directive that came out was to replace the aluminum sectors with steel sectors that could not be bent. There were also going to be interim inspections to be performed until the steel sectors were installed. The fix was cheap and simple but getting it done was not. The actual cost for the modification and changing the locking sectors to steel was $2000 per aircraft but it will take 10 hours to do it and that is what made it expensive. The airline would lose money if they take the aircraft of service for 10hours which could translate into millions of dollars. The Campbell’s discovered that back in 1987, the FAA whose role was to enforce improvements had given the airlines 18 months to comply. United made no plans to install the steel locking sectors. Within a year, Lee Campbell and 8 others will die in an avoidable accident. So why were the airlines not forced to fix the problem sooner? If these large commercial airplanes are grounded it will be an economic disaster. What the airlines does is to lobby to the FAA to allow them to do the fixes over time when the airplanes are in for their normal maintenance. In that way they are not taken out of service. However, when they allow the airlines to fix it over time, the FAA is actually gambling with the lives of the passengers and crew who are flying on these airplanes. After the deaths on Flight 811, the FAA instantly shortened the deadline for fixing the cargo door from 18 months to just 30 days. The pressure of the Campbell’s campaign eventually began to pay off. The vital piece of evidence can prove them right, the cargo door which lay 2 km on the ocean floor. But as articles appeared in the American Press, the NTSB commissioned the US Navy to search for it. A hundred miles south of Honolulu, a deep submersible began to trawl the seabed. They recovered the door and the Campbell’s were notified of this. But before the Campbell’s can see it, the door was quickly transferred to Boeings plant in Seattle. The Campbell’s went in hot pursuit. When they got to Boeing, they would show the door to the Campbell’s which led them to believe that the crucial pieces were already sent to the NTSB. So once again they went to Washington DC. After 3 hours they finally got the pieces they needed from the NTSB and they told them that they were right that it was an electrical malfunction. They assured the Campbell’s that they will fix the airplanes so that the accident will never happen again. However, the Campbell’s were also informed that despite of the findings, the report will not be changed. Even with the evidence of an electrical malfunction in their hands, the NTSB refused to change their report. Then in June 1991 fate intervened. A four year old United 747 was in the airport when the C latch motor started up and the door opened itself. The Campbell’s said that there is no way that the NTSB can deny it any longer that it was an electrical malfunction.
Conclusion
Finally the NTSB issued a revised report that concurred with the Campbell’s version. In a press conference, the NTSB stated that there was inadvertent failure of either the switch or the wiring that caused an uncommanded opening of the door. The Campbell’s felt vindicated after the announcement and happy that they were right all along. They spent thousands of dollars of their own money in their campaign. They were never interested in the financial settlement for Lee’s death. But they did persuade United and Boeing to set up a university scholarship in his name. Susan Campbell said that she would not have been able to live with herself if she did not investigate the death of her son. The Campbell’s knew it was something they had to do and did not even discuss it. But despite long and public campaigns like that of the Campbell’s, critics fear that airline industry has not learned the lessons from Flight 811. The FAA has a dual role. One is to promote the aviation industry and the other is aviation safety and when they are put in a situation where they are between economics and safety, they tend to lean towards economics. Serious accidents caused by known defects continue to occur. In the 1990 known problems in aircraft de-icing systems led to crashes. At least 3 planes have had fatal fires due to known dangers of flammable insulation materials. In 1998, a fully laden 747 blew itself up over the Atlantic when known faults in the wiring ignited known hazards in the fuel tanks. Inevitably, experts are skeptical about the industries record of balancing profit against prevention.

References
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Baehr, B. (2011). Victim's parents absolve hawaii man of role in air disaster. Hawaii News Now, Retrieved from http://www.hawaiinewsnow.com/story/15002555/victims-parents-absolve-hawaii-man-of-role-in-air-disaster

(n.d.). United airlines flight 811. Wikipedia, Retrieved from http://en.wikipedia.org/wiki/United_Airlines_Flight_811

Bridgeman, S. (2009, February 27). Flight 811: The untold story. Sunday Star times. Retrieved from http://www.stuff.co.nz/sunday-star-times/features/1400976/Flight-811-the-untold-story