This Pilot Was Not Fit To Fly (British European Airways Flight 548) - DISASTER BREAKDOWN

3:39 in the afternoon. Flight 548 received its clearance. At 4 o'clock, the plane was pushed back from the gate and for the next few minutes, the Trident was taxied to what was at the time labeled Runway 28 Right, the westbound exit on the side. north of Heathrow. Immediately after takeoff, Flight 548 was expected to turn left to the south, passing over the multiple reservoirs near Heathrow Airport before flying over the town of Staines upon Thames. Before takeoff, the

pilot

s would have executed pre-takeoff checklists that require the leading and trailing edge flaps to be deployed. This is a key point of interest in

this

accident.

The Hawker Siddeley Trident has a rather unique method of setting up the fins. Many airplanes have a single flap lever that operates the hydraulic flap system for both the leading and trailing edges. As we mentioned in previous videos, flaps create a physically larger wing that can generate more lift. They are essential during the takeoff phase and must be deployed accordingly. The Trident had two levers to control the leading and trailing edge flaps independently. It was the flap lever that extends the flaps at the back of the wings. Then there was the drop lever. The Droops were the leading edge flaps of the Trident.

They are not the same as the slats you may already know on other airplanes, although they are similar. In

this

case, the Droop Flap effectively carries the entire leading edge as a single flap forward to give a similar longer life effect while also increasing the performance of the wing in high angle of attack situations. On

flight

548, the aircraft was configured correctly for takeoff. At 4:08 in the afternoon, the plane was taxiing on the runway. Once in the air, Captain Stanley Key banked the plane to the left according to his

flight

plan. There are a number of strict rules that apply to Heathrow and its departures.

In this case,

pilot

s had to follow noise reduction procedures. This required engine power to be reduced 90 seconds after takeoff to reduce noise pollution in residential areas. It is a fairly common practice in many airports, even today. The pilots should also have followed the speed recommendations and that day the plane flew slower than normal. Captain Stanley Key, who was at flight controls, was believed to be under the influence of his undiagnosed heart condition. This could easily have contributed to his poor performance as a pilot at this time. By comparison, he was known at the airline for his efficiency, typically flying textbook departures from Heathrow.

As in his radio broadcasts, this time he showed poor performance as a pilot, which again was unusual for him. But it was what happened next that really set in motion the events that led to a swift

disaster

. You see, after takeoff, and assuming the pilots are following the recommended speeds, the flaps should retract. In this case, it was going to be done incrementally and based on the data interpreted from the flight data recorders, the flaps were setting as expected. The speed of flight 548 was already below the recommended speed. When engine power was reduced 90 seconds after takeoff based on noise reduction requirements, the next stage of flaps was also expected to be raised.

And it was at that moment that a critical error was made on the flight deck. Basically what happened here was that at too low a speed, the drop lever inadvertently lifted. We don't know who raised the flap, although in theory it should have been the co-pilot, Jeremey Keighley. However, the investigation also believes that Captain Key could easily have done this as well if he was suffering from increasing pain that was affecting his judgment. Obviously, the plane responded accordingly and the Droops joined. This decreased the size of the wing and therefore decreased lifting capacity. Enough so that the plane was already out of its flight orbit.

The aircraft had too low an airspeed to operate without the Droops extended. They were approximately 60 knots short of a safe airspeed to execute the Droop retract. The pilots, without realizing it, had stalled and the plane began to fall. At no time from now on will Droops be extended again. Flight 548 had entered an aerodynamic stall from which it would not recover. This is called a "Configuration Change" lock. At the onset of the stall, the Trident's stall recovery lever was activated and the control wheel was pushed forward. We can see this   in the recorded flight data. The input pitch dropped sharply almost immediately after Droops' accidental retraction.

However, as you can see in this graph, the next question is: why is the tone going up again? Inexplicably, the Trident's stall prevention system was manually inhibited during the crisis. It went out, again we don't know who did it. Regardless, it was allowing the pilots to freely lift the nose again, exacerbating the stall. The Trident being a T-tail aircraft, it suffered from a unique design quirk that could have further induced the stall. The horizontal stabilizers that control the plane's pitch could have entered a shadow region behind the wings in a nose-high attitude. This can prevent necessary airflow from reaching the stabilizers.

Like wings, stabilizers and their elevators need airflow to function. There have been similar accidents with T-tail aircraft in which exactly this played a major role. It makes controlling the plane extremely difficult or almost impossible. In a nose-up attitude, the aircraft fell to the ground at considerable speed. The plane had flown over a reservoir, crossed a major road into London and crashed in a field between the road and a residential area in Staines. The impact itself killed most of the people aboard the plane. Numerous witnesses, residents and other members of the public saw the plane go down and first responders quickly arrived at the scene.

One of them was a nurse who was able to care for only two survivors of the initial accident. These two initial survivors were barely alive. They suffered serious injuries in the accident and died before more help could arrive. This devastating accident killed everyone on board the plane; 118 people had died. The investigation found numerous deficiencies in the operation of the plane. It was concluded that the captain failed to pilot the plane properly and that his poor performance was most likely induced by his subtle incapacitation, as stated in the accident report. But there's more to it than that if things weren't bad enough already.

The deteriorated physical condition of the captain and the lack of experience of the co-pilot, the multitude of alerts, the stick shaker, the stall alarm and the stick pusher could have overwhelmed the pilots, to the point of not having been able to deduce the problem. . In the end the pilots lost control and moments later the plane crashed. Many recommendations would emerge from this research. These included requiring commercial airplanes to be equipped with a cockpit voice recorder. Even after this accident, not all aircraft were equipped with one, as it only applied to aircraft of a certain size. The investigation found that pilots could easily confuse the two flap levers, so in the future they should be given different shapes to differentiate them.

Further recommendations were made in the areas of pilot training to highlight the dangers of a “configuration change” type of stall. The Trident pilots had to learn more about the operation of the aircraft's agitator and stick pusher stall prevention systems. The use of the folding seat in the cabin was also criticized. Investigators were keen to note that additional flight crew members who were not at work could have distracted active flight crew members. Excluding acts of terrorism, the Flight 548

disaster

was and remains to this day the deadliest air disaster to occur in Britain. However, it is not the worst air disaster involving the UK or a British aircraft.

Since then other accidents have occurred with substantially higher death tolls and Trident itself was involved in one of them. Next week we'll take a look at that mess. Patreon Outro Well, this was a video that I didn't expect to be as long as it turned out to be. I'm glad we were finally able to talk about this plane and that this accident had a lot to go over, a lot of different things happening. I can certainly say that I have found a new love for the Trident. I have learned a lot about the investigation of this plane, this accident and also the one we will discuss next week.

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