Iranian investigators have disclosed that an ATR 72-500 captain ignored repeated suggestions from the first officer not to proceed with a landing at Tehran during a storm, before the aircraft sustained damage during the touchdown.

The Iran Aseman Airlines aircraft (EP-ATX) conducted an unstable approach in the adverse weather, with high levels of acceleration, says the Iranian Civil Aviation Organisation, citing flight-data recorder information.

It states that the turboprop, arriving from Rasht on 11 June last year, was travelling at 168kt below 2,000ft despite a limitation of 145kt and, as it passed through 850ft, it was descending at more than 1,000ft/min. The crew received glideslope warnings as well as a ground-proximity warning at 810ft.

Upon touchdown the aircraft bounced four times with a maximum impact of over 1.9g.

The inquiry refers to "non-compliance" with crew resource management practice, stating that the captain "did not pay attention" to the first officer's suggestions to divert to Isfahan, or hold, or execute a go-around at different points during the flight.

It says this was part of a "chain of errors" by the captain including failure to comply with requirements regarding take-off or landing in thunderstorm zones, including that prohibiting landing if a storm involving lightning and windshear is within 5nm of the airport.

Tehran Mehrabad weather data showed cumulonimbus cloud at 3,500ft and thunderstorm activity.

The captain had claimed that a forecast from Rasht had mistakenly predicted light stormy conditions, and that this had influenced the decision to proceed with the landing.

But the inquiry says the captain demonstrated no situational awareness regarding information from other flights and Tehran Mehrabad airport controllers, and relied instead on his visual interpretation of the weather.

The investigators rejected suggestions that the aircraft had insufficient fuel to divert, stating that it had enough to fly to Isfahan.

While none of the 68 occupants was injured the ATR sustained damage to its nose-wheels, and components including probes, windows, and static dischargers.

Source: Cirium Dashboard