Pratt & Whitney has redesigned a component of a jet engine being developed for Airbus's top-selling A320neo aircraft after tests revealed "distress" in the engine's hot core.

The problem highlights the strict timetable and performance thresholds in one of the aerospace industry's most closely watched developments, but both planemaker and engine designer said they did not expect any delays or drop in fuel savings.

In an interview, Pratt & Whitney confirmed that it had noticed "insufficient cooling" on a nozzle inside the high-temperature core of the new engine.

The problem developed when the PW11000G engine was being stress-tested, and the redesign is among dozens carried out at this stage of testing, said Bob Saia, Vice President of Development Programs at Connecticut-based Pratt & Whitney.

The United Technologies subsidiary was responding after an industry source, speaking on condition of anonymity, told Reuters that the engine had suffered "significant hot-section damage" during an incident in testing.

Saia declined to go into details of any damage caused, but noted that engineers had been able to complete their tests.

"We saw very local distress, which we corrected by directing cooling for that area of the part," Saia told Reuters.

(Reporting by Tim Hepher, Alwyn Scott; Editing by Peter Henderson)