LOT Polish Airlines Flight 7 increased engine wear, since the engines were under greater load. NK-8-4 engines were not reliable enough. Warranty service life was only 5000 hours, and about half of LOT engines failed after 2000–3000 hours. Because of this, Polish pilots often called the Il-62 "flying coffins". In spite of the low reliability, the airline decided to increase overhaul life intervals to reduce the frequency of repairs, which were carried out in Soviet factories and quite expensive. LOT sent a letter to the Ilyushin Design Bureau containing the results of a test in which it was found that the engines could operate normally
Airline codes accounting or prefix code. This number is used on tickets as the first three characters of the ticket number. The ICAO airline designator is a code assigned by the International Civil Aviation Organization (ICAO) to aircraft operating agencies, aeronautical authorities, and services related to international aviation, each of whom is allocated both a "three-letter designator" and a "telephony designator". These codes are unique by airline, unlike the IATA airline designator codes (see section above). The designators are listed in ICAO Document 8585: "Designators for Aircraft Operating Agencies, Aeronautical Authorities and Services". ICAO codes have been issued since 1947. The ICAO