EasyJet plane cleared Lisbon runway at 30m after pilot 'confusion'
A passenger jet cleared the end of a runway at a low height of just 30m (100ft) after pilots wrongly calculated the length of a runway, a report said.
The EasyJet aircraft was taking off from Lisbon for Luton when pilots "were confused" by taxiway names and thought they had an extra 1.4km (0.87 miles).
The Air Accidents Investigation Branch said planes usually cross the ends of runways at at least 150m (500ft).
An EasyJet spokeswoman said safety was the airline's "highest priority".
Lisbon has since changed the naming of its taxiways.
The pilots thought they had correctly calculated take-off distance from the taxiway they were going to use, but they actually began take-off a third of the way down the runway, rather than using its full length, the Air Accidents Investigation Branch (AAIB) report said.
"A lower thrust setting than required was used for the take off... because it had been calculated for the full length of the runway (which had an additional 1,395m available)," the report said.
A spokeswoman for the AAIB said: "During a normal take-off, a modern aircraft might cross the end of the runway above 500 to 1,500ft."
However, she said the figures were approximate and depended on aircraft type and weight and wind conditions.
The EasyJet pilot said the take-off, although successful, "felt wrong" and reported the problem after landing.
Two weeks later another flight made the same error, the investigation found.
The AAIB report said: "The pilots were confused by the... intersection selections because they did not refer to taxiway names, and the selection could be confused between two runway intersections."
Following the two "serious incidents", EasyJet issued a notice to its flight crews regarding take-off positions at Lisbon, the report said.
A spokeswoman for EasyJet said: "We take events of this nature seriously and will always take action to ensure we maintain the highest standards of safety."