Brief Summary
This video discusses an incident involving an Air France crew who experimented with full thrust takeoffs on empty flights to recreate a strange indication they experienced. This led to unintended consequences, including a near miss with another aircraft due to an extreme climb rate. The video highlights the importance of following standard operating procedures and using simulators for practicing unusual maneuvers, rather than risking real-world scenarios.
- Pilots experimented with full thrust takeoffs on empty flights.
- The experiments led to unintended consequences, including a near miss with another aircraft.
- The video emphasizes the importance of following standard operating procedures and using simulators for practicing unusual maneuvers.
Introduction
The video introduces a scenario where pilots experiment in the cockpit, specifically checking how aircraft systems work, and discusses why this might not always be a good idea. It sets the stage for a story about an Air France crew whose experimentation led to unintended consequences.
Flight 1414: The Initial Flight
On March 28, 2017, an Air France crew prepared for a flight from Paris to Zurich. The crew consisted of two experienced pilots who were also good friends and preferred flying together. The captain had 9,500 hours of total time, with 6,700 hours on the Airbus A320 family, while the first officer had 5,500 hours, almost all on the A320. The video highlights the CRM aspect of friendship in the cockpit, noting that while familiarity can improve operational smoothness, it can also reduce the necessary authority gradient. The flight had only 35 passengers, making the Airbus A318 very light, which can lead to a more twitchy aircraft and excess engine thrust.
Full Thrust Takeoff Experiment
The pilots decided to perform a full thrust takeoff to experience this unusual scenario, which they briefed beforehand, noting the higher acceleration and need for a higher pitch attitude. The video explains that while it's important for pilots to gain practical experience, it should be done safely and with proper briefing. The video also explains the flex temperature system used to artificially limit takeoff thrust, reducing wear on the engines and minimizing fuel consumption and noise.
The Takeoff and Toga Lock
During the takeoff, the first officer pitched up more than usual due to the excess thrust, eventually reaching 24.6 degrees. This activated the Airbus's nose-up protection, causing the flight directors to disappear. The high pitch and back stick input then triggered the alpha floor protection, causing the aircraft to momentarily go into toga mode, indicated by "Toga Lock" on the FMA. The pilots likely didn't notice the brief activation but later reset the system. They continued the flight normally, but were puzzled by the Toga Lock indication.
The Ferry Flight Opportunity
After landing in Zurich, the first officer was asked to conduct a ferry flight from Toulouse to Paris. He invited the captain to join him, seeing it as an opportunity to recreate the strange indication they had experienced. The video explains the standard methods for pilots to troubleshoot technical issues, including consulting manuals, using technical support channels, and utilizing simulator training.
Recreating the Scenario
Two days later, the pilots prepared for the ferry flight in an Airbus A321. The captain, now pilot flying, briefed the first officer about the risk of tail strike due to the aircraft's length and reiterated their plan to recreate the Toga Lock indication with a full thrust takeoff. The video notes that while ferry flights should follow the same procedures as passenger flights, the atmosphere can be more relaxed, sometimes leading pilots to try things out more.
Alpha Floor Activation Again
During the takeoff, the captain pitched up, again triggering the alpha floor protection and Toga Lock. This time, the pilots noticed it and quickly disengaged and re-engaged the auto throttle. The video emphasizes that activating the aircraft's protections on purpose is not the pilot's job and that such maneuvers should be practiced in a simulator.
The Rocket Ship Climb
After being cleared to flight level 140, the pilots leveled off at flight level 100 but maintained climb thrust, causing the aircraft to accelerate to 350 knots. They then selected open climb and a new speed of 220 knots, resulting in an extreme climb rate of over 15,000 ft per minute. The video explains that the pilots were essentially exchanging kinetic energy for potential energy, leading to the unusually high climb rate.
Unintended Consequences and Near Miss
The extreme climb rate triggered a traffic warning in another aircraft cruising at flight level 400, 25,000 ft above them. However, the TCAST system in the Air France aircraft deactivated its warnings due to the climb rate exceeding 10,000 ft per minute, a feature the pilots were unaware of. Air traffic control noticed the unusual climb rate and instructed the pilots to reduce it.
Conclusion and Lessons Learned
The flight landed safely, but the incident highlighted the dangers of experimenting with aircraft systems without fully understanding the consequences. The report concluded that pilots should use simulators for practicing maneuvers and utilize available technical support. The video emphasizes that while nothing dangerous occurred, the outcome could have been different in a more congested area. The video concludes by stressing the importance of learning from such incidents and following standard operating procedures.
