This blog post explores the function and deployment of the Ram Air Turbine (RAT) in the Boeing 787, particularly in the context of the recent crash in India. It details how the RAT operates, the conditions that trigger its deployment, and the implications for the ongoing investigation into the crash.
On June 13th, a significant aviation incident involving a Boeing 787 occurred in India, prompting an investigation into the circumstances surrounding the crash. A key component in this investigation is the Ram Air Turbine (RAT), which plays a crucial role in maintaining aircraft control during emergencies. This post delves into the function of the RAT, the conditions under which it deploys, and its implications for the crash investigation.
The Ram Air Turbine is a small turbine that deploys in emergencies to provide hydraulic and electrical power to an aircraft. In the case of the Boeing 787, the RAT is located on the fuselage behind the landing gear. When deployed, it operates as a constant speed propeller, generating power even as the aircraft's speed decreases. This is crucial for maintaining control of the aircraft during critical phases of flight.
The deployment of the RAT produces a distinctive sound, similar to a propeller at full takeoff power. Audio evidence from the crash site has confirmed the RAT's deployment, indicating that the aircraft encountered significant issues either during takeoff or prior to it. The sound serves as an important clue for investigators.
The RAT provides hydraulic power to the center hydraulic system and electrical power to the aircraft. The Boeing 787 relies heavily on both hydraulic and electrical systems for its operation. It features three hydraulic systems: left, center, and right. Each system has its own pumps, with the left and right systems powered by engine-driven pumps, while the center system utilizes electrical pumps.
The design of the 787 allows it to operate with just one functional hydraulic system, thanks to its redundancy. The RAT is not intended to raise the landing gear but is designed to maintain control of the aircraft by supplying enough hydraulic power during emergencies.
The RAT can be manually deployed by the flight crew, but it can also deploy automatically under several conditions:
These conditions highlight the RAT's critical role in maintaining aircraft control during emergencies.
The deployment of the RAT in the recent crash suggests that the aircraft faced severe issues during takeoff. Investigators will need to determine the configuration of the aircraft at the time of the incident, particularly regarding the landing gear and flap settings. The 787 has a robust takeoff warning system that alerts crews to improper flap selections, which could have contributed to the crash.
The Boeing 787 allows for specific flap settings during takeoff, primarily flaps five and fifteen. The flap configuration at the time of the crash will be crucial in understanding what went wrong. Preliminary analysis of the wreckage should provide insights into the flap settings and overall aircraft configuration during the incident.
The investigation into the 787 crash in India is ongoing, and the role of the Ram Air Turbine is central to understanding the events that transpired. As more information becomes available, it will be essential to analyze the RAT's deployment and the aircraft's configuration to uncover the causes of this tragic incident. With over a thousand Boeing 787s operating worldwide, the findings will have significant implications for aviation safety and operational protocols.
