Investigation into the Ethiopian Airlines Boeing 737 Max crash is likely to be scrutinised as much for impartiality and independence as for its analysis of technical and operational circumstances.

Under ICAO standards Ethiopian authorities are poised to lead the inquiry into the 10 March accident involving the Nairobi-bound flight ET302, which occurred just outside Addis Ababa.

But Ethiopian investigators are likely to face pressure for full transparency – not just to satisfy concerns over the 737 Max, following the airline’s decision to ground the type, but to ensure there is no repeat of the controversy which tainted a previous fatal 737 accident probe involving the same carrier.

Lebanese investigators conducted an inquiry into the loss of Ethiopian flight ET409, a Boeing 737-800, which crashed into the sea just 4min after taking off from Beirut in February 2010.

The inquiry concluded that the crew lost control of the jet as a result of “inconsistent” flight-control input and “mismanagement” of airspeed, altitude and attitude, adding that the aircraft was out of trim.

It stated that the first officer failed to demonstrate sufficient assertiveness to intervene despite multiple warnings – including stick-shaker activation – and evidence that the captain, who was flying, was showing signs of disorientation and loss of situational awareness.

The inquiry attributed the crash to a combination of “failure in basic piloting skills” by the captain, combined with inadequate crew resource management from the first officer, and queried the decision to pair the two.

While the pilots met Ethiopian’s criteria for pairing the inquiry pointed out that their levels of experience “did not constitute a comfortable margin”, particularly for operation under demanding conditions.

Despite the in-depth analysis by the Lebanese investigators, both Ethiopian Airlines and the Ethiopian Civil Aviation Authority strongly condemned the conclusions.

The ECAA claimed the inquiry report was an “unbalanced account” containing “factual inaccuracies, internal contradictions and hypothetical statements” which were not supported by evidence.

In an extraordinary formal statement the authority insisted that the most probable cause of the crash was the break-up of the jet following an explosion – the result of sabotage, a lightning strike, or being shot down.

The ECAA rejected the findings of crew mismanagement of the 737-800, claiming that flight-data recorder information revealed stabiliser and roll movements suggestive of damage to the tail section.

Ethiopian Airlines backed the civil aviation authority’s stance, with chief executive Tewolde Gebremariam – who still heads the carrier – stating that the inquiry “wrongly” alleged that the captain lost situational awareness.

“The [flight recorders] clearly show that the pilot was making appropriate inputs in an effort to control the aircraft,” he said, following the release of the investigators’ conclusions.

Gebremariam also stressed that both pilots were “properly trained and qualified” – with the captain having logged over 10,000h in total despite having only 188h in command of 737-800s – and insisted that any contrary characterisation was “pure fabrication”.

Preliminary information disclosed by Ethiopian Airlines following the 737 Max crash states that the captain had logged more than 8,000h, but the carrier has yet to clarify his experience on type. The first officer had accumulated a total of 200h, it says.

Gebremariam, who was photographed at the Max accident site handling wreckage, provided few other details about the crew beyond stating that the captain had been a senior pilot since November 2017 and had an “excellent” record. He was not questioned about the airline’s position over the ET409 accident.

But the Ethiopian side’s hostile reaction to criticism of the crew during the ET409 probe, and its firm claims that external elements brought down the aircraft, could put the inquiry into flight ET302 on a shaky foundation from the outset – particularly against the backdrop of suspicion regarding the 737 Max which emerged after the loss of a Lion Air Max 8 last October.

This suspicion has already prompted Ethiopian Airlines, and a small number of other operators, to ground their Max jets as a precaution, although there is no conclusive evidence linking the Ethiopian and Lion Air accidents.

Flight ET302 came down some 6min after take-off from Addis Ababa, in daylight and good weather conditions – unlike ET409 which had departed in darkness over water in the vicinity of thunderstorm activity.

There is no immediate indication that the Ethiopian authorities would consider delegating the inquiry to a third party.

Investigators will be supported in their inquiry into the 737 Max accident by technical representatives from the US National Transportation Safety Board which is sending a team of four to assist and which will be backed by advisers from the US FAA, Boeing and CFM International.

Source: Cirium Dashboard