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 codes were originally based on a two-letter-system and were identical to the airline codes used by IATA. After an airline joined IATA its existing ICAO-two-letter-code was taken over as IATA code. Because both organizations used the same code system, the current terms ICAO code and IATA code did not exist until the 1980s. They were commonly called two-letter-airline-designators. At this time it was impossible to find out whether an airline was an IATA member or not just by looking at its code. In the 1970s the abbreviation "BA" was the ICAO code and the IATA code of British Airways while