Airbus is developing a fix to an A321neo pitch-up issue, featuring a flight-control system update, which it expects will become available in the third quarter of 2020.
The anomaly is the subject of a European Union Aviation Safety Agency directive requiring operators to introduce temporary revisions to the flight manual.
EASA issued the directive following analysis of behaviour by the A321neo's elevator and aileron computer.
FlightGlobal has learned that issue – which can result in excessive pitch-up – only affects the A321neo in particular remote conditions when combined with specific commanded manoeuvres.
Four conditions are required. These comprise a low approach altitude, below 100ft, in a specific landing condition, with the aircraft characterised by a particularly aft centre-of-gravity, and the crew engaged in performing a dynamic manoeuvre – such as a go-around.
Under these conditions the aircraft could enter a pitch-up situation which EASA has described as "excessive".
FlightGlobal understands the crew would be able to react to the pitch-up to bring the aircraft immediately under safe control, and that there would be no automatic take-over of manual crew input by automatic aircraft systems.
Airbus is offering customers a mitigating strategy involving operational dispatch limitation, which focuses on the area of the flight envelope affected by unusually aft centre-of-gravity balance configurations. No modification is necessary to operational and training procedures.
The airframer insists the situation is "nothing to do" with the fuselage length or the location of the re-engined aircraft's powerplants.
Airbus adds that it has supported EASA's decision to issue the directive and points out that there has been no notification of an issue from in-service aircraft. Development tests, it adds, enabled the airframer to identity a "pro-active improvement".
"Customers have been informed and we are working with them," the airframer says, adding that a final fix, which would remove the centre-of-gravity limitation, is scheduled for the third quarter next year.
Airbus stresses that the A321neo issue has "clear dissimilarities" to scenarios under discussion regarding non-Airbus aircraft, although it does not specifically mention the Boeing 737 Max – grounded in March following concerns over pitch behaviour.