Prima facie, the AirIndia Express incident is intriguing. The aircraft on the left is the one involved in the incident of contact with obstacle after takeoff.
1. Both aircraft have the similar acceleration to 130kts. They cover roughly the same distance. Their mass may vary but for the same ground speed, the distance seems to be the same.
2. Passing 130kts, the aircraft’s acceleration seems to have slowed down considerably to reach 150 kts .
3. 76kt – 135 kt 3395′ covered 135kt- 150kt 3049′ covered Acceleration rate dropped by a substantial 62% after passing 125 kts G/S.
4. The aircraft climbed at normal ROC to reach cruising altitude as the other aircraft.
Possible first impressions.
a. There was no issue with the aircraft weight since initial acceleration was normal and the climb to cruise was also normal as compared to a previous flight on an earlier date. b. The acceleration rate sudden dropping after passing 125-130 kts by 62% could be due to sudden tailwinds of >20kts or a loss of thrust.
c. The crew did not realize the loss of thrust till acceleration or thrust reduction altitude after takeoff. Thereafter the aircraft rate of climb was normal. Points to ponder and wait for the facts to reveal in the preliminary report after 30 days.