On 12 June 2025 at 1:38 pm, Air India flight AI171 (Boeing 787-8, VT-A) in Ahmedabad gave an opportunity to understand how a small technical or operation mistake (configuration error) can turn into a big aircraft accident during the takeoff, that too when both the pilots and the officer can turn into a big aircraft accident. Clive Kundar) was experienced and the weather was absolutely clear (temperature 43 ° C, no bad weather).
What is configuration error?
Configuration error at the time of takeoff means mistake in the settings of the aircraft, which prevents it from flying correctly. This includes mistakes such as wrong settings of flaps, low thrust, premature takeoff (rotation), or landing gear not lifting. All these things affect the aircraft’s ability to rise and height, which can stall the plane or lose control.
Understand the accident
plane: The Boeing 787-8 Dreamliner was a state-of-the-art, long distance aircraft with a GE GENX engine.
flight: London Gatwick from Ahmedabad, a distance of about 4,200 km. The aircraft was completely fuel.
Circumstances: Clean weather, 43 ° C temperature, runway just 180 feet above sea level. The air was thin due to the heat, which reduces the lift and thrust.
Accident: 5–9 minutes after takeoff, the aircraft fell in Meghani Nagar (residential area of ​​Ahmedabad). The aircraft could reach only 825 feet height and its speed was 174 not (320 km/h), while 787 needs a speed of at least 200-250 not on this weight. In the crash video, the landing gear (wheel) of the aircraft was seen below, which should not be in takeoff.
Why is the configuration error considered to be the biggest reason?
The takeoff is the most risky part of the flight. The right flaps, thrust and rotation speed (VR) are very important. The scope of mistake in hot weather decreases even more.
Possible mistake: If the flaps are very low (eg flaps 0), then it becomes difficult to make a lift for the aircraft. At the same time, more flaps (eg flaps 20), the drag increases so much that the aircraft cannot go up. In hot weather like Ahmedabad, pilots have to keep very accurate settings. If the flaps had been wrongly selected here, then the aircraft would not have got the right height.
Human omission: Pilots may have been entangled in the message of an alert or ATC or have not been able to cross them properly. Even though Boeing 787 has an electronic checklist, it can also be ignored under haste or pressure.
Decrease in thrust
The power of the engine decreases due to heat, so it is very important to set the right thrust for takeoff. If the pilots have accidentally selected a low thrust or have falsely calculated the weight, then the aircraft would not have been able to go up rapidly. The aircraft also needed additional strength due to heavy fuel.
What happened in the Ahmedabad incident: This 787 aircraft was going on a long distance flight and its weight was almost the entire limit (227 tonnes). The flight management system (FMS) must have had any mess or the pilots may have made a mistake in setting the thrust (the power of the engine), so that the aircraft could not get the necessary strength to fly. For this reason, the speed of the aircraft (174 knots) and height must have been reduced.
If the aircraft had taken off from the middle instead of the entire 3,600 meters of the runway (interaction takeoff), then this situation could have worsened, because then the scope of mistake decreases further.
Human Factors: Pilots usually rely on the data recorded in the FMS so that the engine strength can decide. But if information like weight, temperature or length of runway is wrong, then the engine gets less strength. Fatigue or pressure to fly quickly (such as flight time) can also be the reason for this- even if the pilots are experienced like Sabarwal and Kundar.
Premature rotation
Rotation means raising the front part (nose) of the aircraft while flying so that the aircraft can rise above the ground. This work is done on fixed speed (VR), which usually contains 140–160 knots for aircraft like 787 (depends on weight). If the aircraft tries to rise up before this speed, the aircraft does not get the lift (power to rise up) properly. Due to this, the back of the aircraft can hit the runway or the aircraft can fall unstable in the air, especially if the speed remains low even after the takeoff.
What happened in Ahmedabad: The speed of the aircraft was recorded (174 knots), it seems that the pilots probably tried to lift the aircraft before the fixed speed, due to which it could not reach the necessary speed (200-250 knots).
The heat of Ahmedabad also reduced the lift of the aircraft, due to which he had to cover a more distance on the ground. If the pilots rotated quickly, this is why the aircraft was struggling to take height (only 825 feet). The landing gear (wheels) were below, which seems that the pilots did not start the process of taking the aircraft to climb (climb)- perhaps due to an emergency of an emergency.
Human Factors: If the VR (Rotation speed) has been fixed wrong due to wrong weight or temperature, or the pilots have not read the speed meter properly, then it can try to lift the aircraft quickly. In addition, if the co-officer (first officer) did not stop the Captain’s mistake (CRM i.e. Crew Resource Management), then this mistake can cause a major accident.
Landing gear not lift
After takeoff, the wheels are turned up so that the drag is reduced and the aircraft can climb easily. In the video of the accident, the wheels were seen below, that is, either the pilots forgot them, or it was deliberately done because of any emergency. But this further weakened the speed and climbing capacity of the aircraft.
Human Factors: Pilots can forget to uplift the landing gear (wheel) due to a wandering thing (eg stall alert or engine disturbance). Or the pilots would have deliberately kept the gear down so that they can get back on the runway quickly. But Mayday calls and accidents seem that the time was over.
Crew Resource Management (CRM) disturbances
The correct crm means that there should be a clear conversation between the two pilots and the words of each other should go ahead and move forward. If Captain Sabarwal misrepresented a setting like flaps or thrust and the first officer Kunder did not check it properly, then the mistake could not have come to see. Many times, Junior hesitates to say something due to more respecting senior pilots in some airlines. However, Air India’s training system is according to ICAO (international standard).
It is clear from the Mayday call that the pilots understood a major problem, but the accident happened in just 5–9 minutes, which seems that the team may not take the decision on time or the coordination was weak.
Trust on automation
The 787 aircraft makes calculations related to the flight management system (FMS) takeoff, but if wrong information (such as weight or temperature) is added to it, then all the calculations may be wrong. Many times the pilots rely in a hurry and do not check the results of its results. Although there is very little disturbance in modern aircraft like 787, if there is any problem in the system, then the pilots have to manually handle.
Environmental tension
In the scorching heat of 43 ° C, pilots may have physical discomfort (such as water deficiency), which can gradually affect the ability to make decisions. Long duty or scheduling pressure (which is common in long distance flights) can also cause fatigue, which reduces vigilance.
Although there is no sure proof of fatigue, the sudden occurrence of the accident indicates that no major mistake could be corrected in time- it is possible that the pilots were not as vigilant at that time as it was necessary.
Other possibilities
-Pilt’s mistake or takeoff disturbances (70–80%)
The aircraft has a very low height (825 ft), low speed (174 knots), and the landing gear down clearly indicate that there was a major mistake in the setting of the takeoff (such as flaps wrong sets, the engine strength is reduced, early rotation, or not to up the gear after the takeoff). The heat and heavy fuel load of 43 ° C made the situation more difficult, which made a small mistake.
–In the engine failure or bird strike (10–15%)
In the video of the accident, the sound of the engine was not heard and the Mayday call seems that there was a lack of strength in the aircraft. There is also a risk of bird strike in Ahmedabad or there could have been a technical fault in the engine. But the failure of the two engines simultaneously is a very rare incident (1 time in 10 lakhs). The 787 Genx engines are quite reliable. Given the wrong situation of the aircraft, the pilot’s mistake seems more possible.
-The decrease in performance (5–10%) due to the cord
The heat of 43 ° C reduced the lift and strength of the aircraft, which required the perfect setting for takeoff. However, this cannot be the only reason for the accident because aircraft like 787 have been designed only for warm and height areas. The FMS system takes into account the temperature. Yes, if the entire part of the runway was not used (interaction takeoff), then this problem would have increased further. Nevertheless, the direct reason seems to be the fault of the pilots.
-Tetal or structure malfunction (2–3%)
Due to any technical or structure malfunction in the aircraft, a sudden decline could come, but the security record of 787 is excellent and no such incident happened before. Seeing the condition of the aircraft (speed, gear down), it seems that it happened not by sudden technical fault, but by human mistake.
-Red or terrorist attack
There is no such information or evidence that there is any kind of conspiracy or terrorist attack in this incident.
-Any other incident on the renovation (1%)
The aircraft had flown up to 825 feet, so there is no possibility of any incident like hitting the runway. Air Traffic Control (ATC) system already stops these risks.
So what is the reason for the accident?
Due to the low height (825 ft) of Boeing 787-8, low speed (174 notes), and gear down in the Ahmedabad accident, it is most possible that there was a big mistake in the setting of the aircraft during takeoff (eg flaps wrong, the engine strength, reduced rotation or gear). Its possibility is believed to be 70-80%.
The heat of 43 ° C worsened the situation, causing the pilot’s mistake. Engine failure (10–15%) or heat related problems (5–10%) may be the second possible reasons, but the main reason seems to be a mistake in the takeoff.