Ahmedabad, June 14: Even as the precise reasons that led to the crash of London-bound Air India flight in Ahmedabad on Thursday continue to be unknown, aviation experts pointed out, that the crash might be led by failure of its Ram Air Turbine (RAT), a small emergency electricity generator that activates only in the most critical situations to power the aircraft’s essential systems.
If this technical aspect is yet to be analysied and highlighted, the scene before the crash indicates so, opined some Aviation Trainers and veteran Captains.
The fierce video, before and after the crash, showed that the aircraft's wheels down at an altitude of approx. 600 feet and the flaps leveled—a low murmur, which could be the sound of the Ram Air Turbine (RAT).
The RAT operates only when all primary power systems—those drawing power from the engines—fail. It also activates if the Auxiliary Power Unit (APU) does not work, and even the battery unit fails. Only then the RAT begins functioning automatically.
Unlike in other aircraft, pilots in Dreamliner planes cannot manually switch on the RAT—it activates automatically in extreme emergencies, the experts underlined.
Activation of the RAT indicates that all major power systems on the Boeing 787 Dreamliner, which depends entirely on electric systems, may have failed at that altitude of 625 feet.
According to a retired Air India Pilot and aviation trainer, both engines could have been failed, along with the generators they power.
Otherwise, the engines were running, but both Integrated Drive Generators (IDGs) were not functioning, and the APU also failed, along with insufficient battery power.
The pilot's message—“No thrust, losing power & plane not taking lift”—must be understood in this context. However, the pilot did not say the engines totally failed. Saying “no thrust” and “no lift” more likely means that although the engines were on, they were not producing thrust or lift, he pointed out.
This could mean the engines were in idle mode and not generating enough power, or only one engine was working. “No lift” could also point to the flaps being in a neutral position.Additionally, an imbalance in the distribution of cargo and passengers could make it harder for the plane to gain altitude, leading to such a scenario, suspected the experts.Since the engines are ultimately controlled by the electrical system, any failure there can eventually render the engines non-functional, they added.
The fact that the engines alone wouldn’t have triggered the RAT it implies that the APU and battery both failed due to technical glitches. However, the aviation experts said that the RAT alone could not have helped this aircraft land safely. It only provides temporary power until the other systems are restored. The fact that the pilots could not identify or fix the root cause in that short span led inevitably to the disaster and the Boeing 787 Dreamliner ultimately crashlanded on a medical hostel in the Ahmedabad City.
Thus, it’s obvious that , in case of a loss of primary power, the RAT ensures vital systems remain operational, enabling pilots to maintain control and land the aircraft safely.
However the redundancy of RAT despite power- failure might have caused the crash that wrecked the around 600 feet aircraft into ashed and killed almost 270 lives instantly in volcanic blaze.
Worth mentioning, the RAT in an US Airways Fligt was proved miraculuous in the past.
The "Miracle on the Hudson" in US Airways Flight 1549 demonstrated the importance of the RAT when the aircraft lost both its engines and the batteries ran out all of a sudden in mid-air, allowing pilots to control the aircraft and land it safely on the Hudson River.
