Ten percent of the 40 crashes by Russian-built Tupolev Tu-154s have been in Iran. But Russian experts say its a reliable jet.
The ubiquitous Soviet-era passenger jet remains the chief workhorse of airlines throughout the former USSR.
Almost 40 of the machines (out of some 1,000 produced) have been lost in fatal accidents since it was introduced in the early 1970's, a record that Russian experts insist is equal to that of comparable Western aircraft, such as the Boeing 727 and 737.
Four crashes in Iran
But four of those Tu-154 accidents - a disproportionate 10 percent of them - have occurred in Iran over the past 16 years, killing almost 450 people and leading some experts to scratch their heads for an explanation.
"They have a long experience with the Tu-154 in Iran," says Oleg Panteleyev, editor of the Russian-language online aviation newspaper Aviaport.ru. "They have dozens of these aircraft in service, along with lots of highly qualified specialists and local servicing centers."
Though Iran has trouble purchasing new airliners due to international sanctions, Mr. Panteleyev says there is no difficulty in obtaining spare parts for the old Tupolev planes, which are not subject to any restrictions.
Three of the Iranian accidents have occurred with planes flown by Iran Air Tours, a mainly domestic charter operator that lists ten Tu-154's in its inventory.