A lack of IT testing led in part to the disastrous opening of Heathrow's Terminal 5, British Airways' chief executive, Willie Walsh, told MPs this week.
The building of the terminal was not finished on time, and IT testing and staff training were "compromised" as a result, Walsh said at the Transport Select Committee on Wednesday.
The terminal opened on 27 March. It immediately ran into a range of problems that "cascaded" and led to losses of £16m for BA in the first five days of operation.
Software problems were a main cause of the airline's problems. Walsh said the main IT problem with the baggage system was a software filter that was mistakenly left in place after the system - designed by BAA - went live.
Walsh said the filter was used during the testing period to ensure the messages generated were restricted to the BAA operation, and were not sent out further than that. But because it remained in place after the terminal opened, it interfered with the messages coming into the system, meaning the system could not recognise a number of bags.
One other IT problem at the terminal concerned server capacity. Walsh said the servers had not been able to cope with the "significant increases" in the volume of bags going through.
The amount of messages the servers were coping with was significantly more than the amount run on them during modelling, and more server capacity is still required.