The faulty gauge, the altitude director indicator (ADI), failed on the Boeing 747's penultimate flight from Tashkent to Stansted, and despite being worked on by ground crew at the airport failed again shortly before the plane crashed minutes after taking off on December 22.
A Korean Air engineer killed in the accident along with three other crew members was among those who examined the instrument.
The report, which reaches no conclusion about the cause of the crash, says the crew was warned that the instrument was faulty after take-off.
Both captain and co-pilot would have had ADIs, and the fault became apparent on the previous flight.
The flight engineer told a Korean Air ground engineer the captain's gauge was faulty and that he and a Stansted-based maintenance engineer had worked on the fault.
The local engineer told investigators that "the operator's [Korean Air] engineer said that he would complete the technical log". No copy of the log was left at Stansted.
Last night it emerged that the tail of the 747 contained 300kg of depleted uranium as a counter-weight, and that emergency services may have been exposed to radioactive uranium oxide.
A Boeing spokesman said: "The company began using depleted uranium in the early 1960s. Boeing replaced it with tungsten ... in the early 1980s. The Korean 747 was delivered to the airline in June 1980."
The spokesman said the depleted uranium would have had to be heated to a temperature in excess of 800C before uranium oxide was emitted, and that emergency workers would not have been at risk.
