But after 17 years of United States sanctions that have prevented the Islamic Republic from buying new Western planes and spare parts, he said he now felt ashamed before his passengers and angry over American policies, which he said, were responsible for Iranian plane crashes that have left more than 1,700 passengers and crew members dead.

The sanctions have prevented oil-rich Iran from updating its fleet, forcing it to use substandard Russian planes and to patch up its older jets far past their normal years of service, drawing on spare parts bought with increasing difficulty on the black market. Rarely a year goes by without major airline accidents, and most Iranian planes, including the 727, are forbidden to operate within the European Union.

“Our planes are completely worn out,” Captain Shahbazi said, emphasizing that mechanics were doing what they could to keep the planes flying safely. That was getting harder and harder, he said. “In reality, each flight can be our last.”