If you haven't flown the sub-continent, this may seem unbelievable. If you have - just another day.
AvHerald Link to StoryIndia A320 at Kolkata and Nagpur on Jul 22nd 2017, "inexplicable" performance degradation.
By Simon Hradecky, created Tuesday, Jul 25th 2017 19:35Z, last updated Tuesday, Jul 25th 2017 19:37Z
An Air India Airbus A320-200, registration VT-EXE performing flight AI-676 from Kolkata to Mumbai (India), was climbing out of Kolkata, however achieved an unuusally poor climb rate, was not able to accelerate to normal cruise speeds and levelled off at FL200 after a continous climb for about 30 minutes. The aircraft subsequently attempted to continue the climb but could not climb above FL240. The crew continued the flight at FL240 and about 310knots over ground for another about 45 minutes then needed to divert to Nagpur (India) due to running low on fuel. While on final approach to Nagpur, when the crew was about to lower the gear, the crew discovered the landing gear had remained extended all the flight. The aircraft landed safely in Nagpur, about 530nm west of Kolkata, about 2.5 hours after departure from Kolkata.
The aircraft remained on the ground in Nagpur for about 2 hours, then departed again, achieved normal climb performance, climbed to cruise level FL360 and landed safely in Mumbai with a delay of 3:45 hours.
On Jul 25th 2017 the airline reported both pilots were de-rostered due to not retracting the landing gear after departure from Kolkata and continuing to fly without detecting that the landing gear was still extended despite the unusually poor performance. The occurrence is being investigated by the airline.