Aircraft Accidents and Lessons Unlearned LII: Eastern Airlines Flight 980

Mount Illimani with La Paz in the foreground Picture by Donald

On January 1, 1985, Eastern Airlines flight 980 (EA980), registration number N819FE, a Boeing 727-225A crashed at 2040 (8:20 PM) local time while descending towards a landing at La Paz airport in Bolivia. The aircraft impacted Mount Illimani at the 19,700-foot height mark; the aircraft was destroyed by impact forces.

A file (the only one found) of the Bolivian accident report, ‘Eastern%20980%20and%20Letter.pdf’ included Appendix A: a November 5, 1985, Letter to the NTSB Chairman; Appendix B: the Republic of Bolivia Ministry of Aeronautics report and Appendix C: the safety recommendations of Captain Don McClure. The Bolivian report in Appendix B stated, “… since the cockpit voice recorder [CVR] and flight data recorder [FDR] could not be recovered because of bad weather conditions and the inaccessibility of the terrain, the conclusion of this report has not been fully confirmed.” This statement was important as, among other reasons, the National Transportation Safety Board (NTSB) planned to get the FDR and CVR recorders at a later date.

The accident investigation and its subsequent report were accomplished and prepared by the Comision Investigadora de Accidentes e Incidentes de Aviacion (Board of Inquiry on Aviation Accidents and Incidents) of the Direccion General de Aeronautica Civil (Civil Aeronautics Bureau). The EA980 accident was assigned NTSB Accident Identification number DCA85RA007. Per the NTSB website, the foreign authority – Bolivia – was the source of accident report information. There was no NTSB docket information.

Working from air traffic control recordings of communications between EA980 to both Santa Cruz and La Paz control, the events that led to the accident were adequately pieced together. EA980’s last transmission: “La Paz, EA980 leaving flight level 250 [25,000] for 18,000 at this time,” was normal, relaying no sense of urgency or confusion from the flight crew. There was no reason to question that EA980 impacted Mount Illimani without an emergency taking place; EA980’s course, as discovered by post-accident analysis, had deviated twenty-six degrees from the assigned approach, which would account for the aircraft wandering into a course that would align with the mountain’s location.

In absence of any conflicting information, the aircraft hit terrain; given the time of night and the lack of identifiable landmarks, it is clear the flight crew became either disoriented or they intentionally veered away from the assigned flight path. No emergency calls or desperate transmissions, the aircraft, which was mechanically sound, had likely flew a controlled flight into terrain. This was a practical answer; the loss of recorders and survivors would not contradict this possibility.

Yet, Mount Illimani is a sizable land mass; would the flight crew have not seen it? Eastern 980 may have had a similar disadvantage as the Titanic, in that meteorological and astronomical conditions may have assisted in dooming the flight. With the Titanic, the calm sea and the dark of night hid the iceberg from view until the last moment. Could something similar have happened to Eastern 980?

Through the report, there is no reference to Lunar illumination, such as if the Moon was ‘out’, what time the Moon was seen and at what phase it was in. On January 1, 1985, the Moon was in Waxing Gibbous; this phase of the Moon appears from daytime to early evening and its brightness is from 59% to 99%, depending on what point of the Waxing Gibbous phase it was in. If the Moon was overhead, it might have provided an adequate illumination on the terrain below. However, the Moon would have been close to or below the horizon during EA980’s last minutes.

Were there adequate ground lighted references, e.g., cities, towns or highways for the crew to get a visual reference. It is unclear, but unlikely that in this part of Bolivia, these types of illuminations would have been enough to aid the flight crew in their situational awareness. Would Mount Illimani have suddenly ‘appeared’ as Eastern 980’s lights painted it? Were the B727 aircraft’s Krueger flaps even extended past five degrees, allowing the wing lights to point forward or were the wing root lights illuminated? Not likely as EA980 had not reached the point in its approach to run the landing checklist. The B727’s landing lights were most likely off.

What was the weather like? Did meteorological conditions hamper EA980’s flight crew by blotting out any celestial illumination from the sky, perhaps a starfield behind Mount Illimani or even the descending Moon? The accident report stated that, per La Paz control on January 1, 1985, the following weather was at the La Paz field: “La Paz 080/12 unlimited, 3SC500 iCB750-3AS2400-07/04 QNH millibars 1034 inches 30/53. Cumulonimbus SE of airfield.” Several pilots familiar with reporting international aviation weather were consulted, but the language of this transmission has changed since 1985; it was unclear what conditions were above 12,000 feet. However, EA980’s last weather report reflected the weather on the La Paz airfield, not where EA980 was flying near Mount Illimani. In addition, investigators believed EA980 drifted off course to avoid flying through inclement weather.

Finally, had the flight crew turned on the interior lights, thus eliminating their night vision? Was the pilots’ night vision compromised by the instrument lights enough to nullify any possibility of discerning shapes outside the windscreen? If they looked out, could they have separated Mount Illimani’s silhouette from the inky blackness of dark? It is reasonable to conclude that EA980 flew a controlled flight into Mount Illimani; that is a practical conclusion, almost impossible to disprove. Any responsible organization would have accepted the logic of that probable cause.

In Appendix C, Captain McClure retraced each leg of EA980’s accident flight plan and provided several observations and recommendations, based on his flying experiences and familiarity with La Paz. He gave insight into cultural and procedural problems that he felt contributed to unsafe practices that led to the flight 980 confusion as well as concerned him regarding ground crew practices. It was unclear whether any of Captain McClure’s recommendations were acted upon, indeed even added to the accident record.

It was the Appendix A letter that was most confusing. Among the items found in the Google search was a letter allegedly written nine months after the accident, outlining an attempt by inexperienced climbers to find the CVR and FDR recorders. To be clear, for professional climbers to ascend Mount Illimani to rescue survivors would have been a noble effort. However, EA980’s impact was too catastrophic; there never were any survivors to save; this fact was known within hours of the accident. To recover the deceased and/or their effects, an effort, though well-intentioned, would have been fool-hardy, even for the most experienced climbers; it would have had to be weighed against the risk – by professional climbers. Would the ends have justified the means? The odds for costly loss of further lives might have outweighed the benefits. There were no survivors, no effort would have changed that.

The letter to the NTSB Chairman, written by the field NTSB investigator who made the climb to the 19,700-foot level of Mount Illimani, detailed how he led a team of other inexperienced climbers to recover the recorders. The undertaking was hampered by team members’ health issues, equipment problems, food and water problems and other necessities, such as adequate shelters not being available during the ascent. The field investigator explained how he researched his ‘training’, “… about high-altitude mountain climbing so as to be well informed on the physiological factors associated with the high altitude and lack of oxygen.” Research? Why not hire experienced climbers or take a qualified climber with the team? The climb, as executed, was accomplished with arrogant inexperience.

If a ‘lack of oxygen’ affected one’s reasoning, then oxygen deprivation was present in the meeting that led to the expedition. It would have been incumbent on NTSB management to terminate any plans by this or any NTSB investigator from attempting something so foolhardy, but even NTSB management could not be depended on to do their jobs and stop such an unsafe venture.

Then there was the recorder recovery. The field investigator made it to the accident site, only to be defeated by a basic lack of knowledge of where the recorders were in the fuselage. Recorders are found in the rear of the aircraft, but their exact location can vary from operator to operator. For instance, a cargo operator may have the recorders located in the aft airstair while a passenger operator might have located them in a belly cargo hold, overhead bin or at the aft bulkhead. It was clear from the letter that the field investigator did not know where in the airplane the recorders were.

It is discouraging to read about these exploits and to accept that personal safety was not at the forefront of NTSB investigations; I would hope that NTSB field investigators today do not follow such foolish actions but accomplish their jobs safely with common sense dictating their actions – not government bureaucrats and employers of mismanagement. Not all accident sites are accessible, whether because of a lake’s depth, a mountain’s summit or the threat of carnivorous wildlife, no recovery of evidence is worth more lives to acquire. When I investigated the LAS DC-9 accident outside Mitu, Colombia, I did not drop into the jungles occupied by the drug cartel to recover evidence; the Colombian Army did with support aircraft and trained experts. That is common sense.

The Eastern Airlines flight 980 accident was tragic. Was it preventable? Most likely. It certainly was not intentional; there was no action taken by air traffic or the flight crew to misdirect the B727 into the mountain. To be clear, ‘preventable’ is often a hindsight view; we often cannot see far enough to prevent something unless it is clear what we are doing is wrong. Past successes (prior flights into La Paz) lull us into a false sense of security where we cannot see the forest for the trees. That is why we must get it right. But it also means that we learn from the best root cause possibilities. Could we prove, beyond a shadow of a doubt, that Eastern 980 was a controlled flight into terrain? No. But the NTSB could have allowed the assumption to dictate safety procedures to prevent controlled flight into terrain, nonetheless. And perhaps, they should have given Captain McClure’s recommendations another look.

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