Analyzing Tara Air Flight 197
BREAKING: Preliminary report released
I love writing on aviation, especially in Nepal. Views from aircraft there are the best in the world. Airports in Nepal are nostalgic, and can remain that way, but some things have to change…
On May 29, 2022, Tara Air Flight 197 killed 22 people when it crashed about 12 minutes from Pokhara’s then-regional airport (VNPR). Operating the flight was a de Havilland Canada DHC-6 Twin Otter, registered as 9N-AET. The flight left Pokhara at 9:55 am (NPT) and its wreckage was discovered nearly a day later near Sano Sware Bhir in Thasang, Mustang. It was bound for Jomsom Airport (VNJS) in Gandaki Province, Nepal. Two pilots were in control of the flight. One, Captain Prabhakar Ghimire, was the pilot-in-command. He was known in the industry as a pilot who did not take chances. In addition, he was an instructor pilot with “vast experience” flying Twin Otters. His co-pilot was Utsav Pokhrel, who had just about one year of service with Tara Air.
Tara Airlines is a subsidiary of Yeti Airlines, the company whose ATR-72 crashed in Pokhara on January 15, 2023. Formed in 2009, Tara took over operations of Yeti’s STOL (Short Takeoff and Landing) flights in Nepal, using its de Havilland DHC-6 Twin Otters and Dornier 228s. According to its website, Tara Air now operates three Twin Otters (DHC6-300 and DHC6-400). Below is pictured the accident aircraft, taken prior to the incident at an unknown date at Jomsom Airport.
The preliminary report (the final report will be released following review by the International Civil Aviation Organization [ICAO]) states that the probable cause of the accident was “the flight crew’s failure to monitor and maintain the proper course while inadvertently flying in IMC conditions with the aircraft Terrain Avoidance and Warning System [TAWS] inhibited which resulted into a CFIT accident.” It adds 8 contributing factors:
1. The flight crew’s failure to follow the SOP of the company
2. The aircraft flight operation with TAWS inhibited during deteriorating en-route weather condition.
3. Loss of situational awareness of crew
4. Deteriorating en-route weather
5. Less experienced copilot for that sector and high crew gradient
6. Poor CRM during the flight
7. The whole cockpit duties [both PF and PM] were undertaken by the PIC, which likely impaired his performance.
8. Underutilization of the available Navigation instruments.
There is a lot to break down there. So, let’s start with the asserted probable cause. “IMC conditions” means that the weather conditions require pilots to fly primarily in reliance on their instruments. Flying “inadvertently” into IMC conditions suggests that either the conditions changed quickly and the pilots were not prepared for such changes, or the pilots were flying under VFR (visual flight rules) initially, and thus either did not have the equipment and/or training to fly under IFR (instrument flight rules). To put this simply, VFR flying requires the pilots to be able to see certain distances in order to safely operate the aircraft. IMC describes weather conditions that makes VFR difficult or impossible. When a flight is expected to encounter IMC conditions, the pilots are required to have training and the necessary instrumentation to fly without relying on external visual cues. Therefore, as the weather conditions deteriorated on this flight, the pilots were expected to turn to flying by their instruments without relying on external visual cues. Also of note, a CFIT accident refers to a “Controlled Flight into Terrain.” I have previously explained what that is here. In short, a CFIT is an avoidable crash into the ground.
That brings us to the second probable cause factor: the “inhibited” TAWS. Terrain Avoidance and Warning Systems use a radio altimeter reading to calculate the proximity and closure rate of nearby terrain. As obstacles become dangerously close to the aircraft’s trajectory, an alert notifies the pilots so they can take evasive action. There are different classes of TAWS, but what is more important here is the description of the TAWS on this flight, “inhibited.” Investigators who spoke to the Kathmandu Post stated that either the TAWS was not functioning correctly, or at all. One investigator stated that the system provided a warning three times, but did not make an audible sound suggesting the pilots were unaware of the alert. Deteriorating weather combined with malfunctioning or absent terrain proximity warnings appear to have caused the pilots to lose awareness of where the aircraft was relative to its surroundings. These circumstances comprise the probable cause and factors 2, 3, and 4 of the contributing factors.
Before delving into the other factors, it is worth noting that flying to and from Jomsom Airport is particularly challenging. To start, it is located at 8,976 feet elevation. Its runways 06 and 24 are just 2,674 feet long and 66 feet wide (815 X 20m). The terrain around it is rugged, high, and unforgiving. Because of the height of the surrounding terrain, pilots fly a portion of the flight through gorges. From 1960 through April 2019, the Jomsom route was the second most lethal in Nepal. Moreover, remote weather coverage in the area is lacking, leaving pilots to rely on other pilots to ascertain the viability of flight. In the case of Tara Air Flight 197, it began the day with a weather-related delay. Two Summit Air flights ended up departing Pokhara ahead of the Tara flight, but the pilots of those aircrafts apparently told Tara Air Captain Ghimire that weather conditions at 12,500 feet were sufficient for flying. Thus, Captain Ghimire elected to start his flight. Unfortunately, irrespective of whether the Summit Air pilots correctly reported the weather, conditions on the Pokhara-Jomsom route are often treacherous because they swiftly change and the surrounding mountains can cause sudden turbulent air. Furthermore, the area is quite remote. Rescuers searching for the Tara accident flight resorted to tracking ping locations of Captain Ghimire’s phone to help locate the downed aircraft because the weather made it so difficult to find it.
This brings us to contributing factors 5, 6, and 7. Each of these relates to how the flight crew managed the duties of the flight. Nepal’s Civil Aviation Authority (CAAN) was quite critical of how the flight crew operated during this flight. It noted:
5. Less experienced copilot for that sector and high crew gradient
6. Poor CRM during the flight
7. The whole cockpit duties [both PF and PM] were undertaken by the PIC, which likely impaired his performance.
Captain Ghimire, 62 years of age, was the “PIC” (pilot-in-command). This is customary for senior officers on potentially challenging flights. While the report does not say how—or if—the crew determined their roles ahead of time, it appears that Captain Ghimire was flying the plane (PF), which normally would mean then that co-pilot Pokhrel had adopted the role of pilot monitoring (PM). “CRM” here refers to crew resource management. CRM means utilizing all of the available tools at a flight crew’s disposal to effectively and safely operate a flight. This includes instruments, but also means sharing tasks, information and observations between the operators. During the Tara flight, good CRM would have had one pilot handling the controls and safely operating the aircraft, with the other monitoring the instruments, making proper callouts and generally observing the conditions both internally and externally. In the event of sudden changes or problems, crews exhibiting good CRM split the duties necessary to restore order or bring the flight to a safe resolution in response to the circumstances. To do this well requires excellent communication between crew members.
The report explicitly states that this crew exhibited poor CRM and that the “whole cockpit duties [both PF and PM] were undertaken by the PIC, which likely impaired his performance.” In plain language, Captain Ghimire seems to have taken on all the responsibility of the flight, perhaps ignoring his co-pilot or possibly because his co-pilot simply remained silent or unhelpful for whatever reasons. This may be the result of what CAAN’s report referred to as a “high crew gradient.” The gradient of a crew refers to the power disparity between the pilot and co-pilot. In some airlines, there is a culture in which very senior or ranking pilots do not expect—or like—to be questioned by inexperienced or lower ranked co-pilots. Other times, this dynamic is more culturally driven by the society in which an airline operates, even if discouraged by the airline itself. And in still others, this gradient only exists in the minds of specific pilots and is not encouraged by either the airline or home culture of the crew. Whatever happened here, investigators stated that crew gradient is a frequent problem in Nepal. CAAN’s National Aviation Safety Plan for 2023 to 2025 noted that an advisory was circulated recommending airlines implement a Crew Resource Management Training Program, but it is currently unclear how this may (or may not) have been incorporated into Tara Air’s policies. Ideally, CAAN would make such training a requirement, instead of an advisory, moving forward. Such training is extremely helpful for overcoming the obstacles created by crew gradients.
Another contributing factor mentioned in the report was the “underutilization of the available Navigation instruments.” This statement is nebulous at best. It seems to suggest that there were functioning navigation instruments that investigators somehow determined were not used by the pilot(s). Until the full report is released, all we can do is speculate, which I will not do here. Equally vague is the contributing factor regarding failing to follow company SOPs. I could not find a publication of Tara Airlines’ SOPs (which stands for Standard Operating Procedures), so it is impossible even to speculate about what investigators are referring to there.
Finally, from a wider perspective, there remains the question of the condition of the aircraft and its requisite instruments. The Twin Otter aircraft was originally delivered to Air Botswana on May 2, 1979, under registration A2-ABL. It moved to Lesotho Airways in December, 1983. On April 2, 1984, the aircraft suffered damage to its right wing upon striking a tree just 200m before landing in Quthing, Lesotho; it was later repaired. The aircraft changed hands a few more times before Garud Air of Nepal acquired it in 1998. Yeti Airways then acquired the aircraft in 2010. I was unable to find more recent mechanical records on this aircraft. Hopefully, release of these records will provide more clarity on what navigation systems were mounted on the aircraft, what condition they were in during the accident flight, and most importantly, will reveal more about what was going on with the TAWS system.
The Questionable History of Yeti and Tara Air
From 2004 to present, Yeti and its subsidiary Tara have had a less-than-stellar safety record. Tara and/or Yeti Air has repeatedly made headlines as among the world’s most dangerous carriers in 2015, 2019, 2022, and 2023, at least. While these are not scientific assessments, in a country like Nepal that highly depends on tourist dollars, even the perception is unacceptable. Over the last 20 years, these two airlines have had 7 fatal accidents and several other dangerous incidents. Aside from the fatal flights of May 2022 and January 2023, Tara experienced fatal flights in 2010 and 2016, and Yeti in 2004, 2006 and 2008. Among those, the flights in 2004, 2006 and 2008 were attributed to the pilots’ violations of various regulations and SOPs, poor training, and/or the company putting profits over safety. The 2010 flight was attributed to “the [] unwise decision taken by the crew to descend without taking the harsh mountain terrain into consideration.” And the 2016 incident was attributed to the “crew’s repeated decision to enter into cloud during VFR flight and their deviation from the normal track due to loss of situational awareness aggravated by spatial disorientation leading to CFIT accident.”
In my previous article discussing Yeti Airlines Flight 691, I spoke at length about CAAN’s moves toward improving safety in Nepal’s aviation sector.
I believe CAAN’s National Aviation Safety Plan for 2023 to 2025 makes many progressive proposals that will definitely improve Nepal’s aviation industry if implemented. An issue the report less explicitly addresses, however, is how it will deal with problem airlines. I created the following charts indicating visually how Yeti and Tara Air compare to the rest of Nepal’s most prolific domestic airlines.
There is a clear indication that Yeti and Tara Airlines have comparatively more issues than the other domestic airlines operating in Nepal. This is not pointed out to embarrass those airlines. Nepal’s reputation as a global tourist destination, however, depends on rehabilitating the perception of its aviation industry. Without question, the broader issues highlighted in my previous article require attention, and CAAN has articulated a concise plan to deal with them. Nevertheless, if targeted areas require enhanced scrutiny, CAAN should not hesitate to take action. With tourism generating over 500,000 jobs and an increasing portion of Nepal’s GDP each year, it is too important not to protect this critical area. Moreover, as if it needs to be said at all, the lives of hundreds of people should not be lost to negligence, corporate shortcuts, or other avoidable reasons.
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