Central Flying Academy Landing With A Tailwind
Why Landing With A Tailwind Increases Your Risk Of An Accident
From the moment you start learning to fly, you're taught to land into the wind, if at all possible. There's no doubt that while you can land with a tailwind, it increases your risk of things going wrong. But at the same time, most GA airplanes have performance charts that let you calculate takeoffs and landings with up to 10 knots of tailwind.
So what's the big deal with tailwinds? There are two major factors: performance, and controllability.
Tailwinds And Landing Distance
Most GA aircraft performance charts give you the same guidance: for operation with tail winds up to 10 knots, increase distances by 10% for each 2 knots.
That means if you're landing with a 10 knot tailwind, your landing distance increases by 50%. That's a big performance penalty. But that's not the only problem.
Tailwind Touchdown Controllability
Controllability on touchdown is another issue. When you're landing with a tailwind, you have a higher ground speed on touchdown (assuming you're flying standard pattern/touchdown speeds). When pilots land fast, they have a tendency of braking more aggressively than usual, and that's where the problems start.
In most tricycle gear planes, 80%-90% of the airplane's weight is on the main gear. But that all changes when you land and hit the brakes. Your brakes are trying to slow you down, but your airplane wants to keep moving forward.
You feel it in the cockpit when it happens. When you brake aggressively, you get thrown forward against your shoulder harness. The same thing happens with your tires. When you aggressively brake, a lot of the airplane's weight is 'transferred' to the nose gear, even though your CG hasn't moved an inch. In many cases, you could have more weight on the nosewheel than the main gear during aggressive braking.
When you combine that load transfer with the crosswind component of a quartering tailwind, you could put yourself in a situation where one of your main gear has little or no weight on it, affecting your ability to keep the plane under control and on the runway.
How Much Tailwind Is Too Much?
When it comes to landing accidents, how much tailwind is too much? Ultimately, it depends on your proficiency. Below, we've picked three landing accidents where the pilot faced less than 10 knots of tailwind. In each of them, there were different factors at play, but all three led to an accident.
Accident 1: Runway Overrun With 5 Knot Tailwind
A Cirrus SR22 was landing on runway 22 with a 5 knot tailwind at KAVX. The airplane, which was near max gross weight, reportedly touched down within the first few hundred feet of the 3,000' runway. However, the pilot wasn't able to bring the aircraft to a stop, and it overran the runway, coming to rest on a 45 degree downslope past the departure end of the runway.
According to the NTSB, at maximum gross weight in the weather conditions of the airport at the time of the accident, the airplane had a calculated ground roll of about 1,250 feet, with a total landing distance of about 2,500 feet. Taking into account the 5 knot tailwind and the 1.69% upslope, this airplane's final ground roll was calculated to be about 1,300 feet, and the total landing distance was about 2,650 feet.
So what happened here? First, runway 22 was being used by other aircraft, which may have pressured the pilot to use the same runway. While the tailwind component was only 5 knots, it increased landing distance by 25%, and gave the pilot little margin for error, especially if they landed long.
While aircraft controllability (left/right control) wasn't at play here, landing distance was. The pilot's decision to land with the tailwind, combined with the fact they only had a 500' margin of error on landing distance, ended with the plane going off the end of the runway. It only took 5 knots of tailwind, but had the pilot chosen to land with a headwind instead, they most likely would have had enough runway to safely stop.
Accident 2: Tailwheel Landing With 8 Knot Tailwind
Anyone who flies a tailwheel aircraft knows how challenging they can be to land in any kind of wind. And when there's a tailwind, landing safely is even more difficult.
In this accident, a Cessna 140 was making a landing with a 5 to 8 knot tailwind. During landing, the airplane touched down hard, and the pilot lost directional control.
The aircraft began side-loading, causing the left main gear to collapse and the left wing to strike the runway, substantially damaging the aircraft.
As with any hard landing or porpoise landing, maintaining control of the aircraft is the first priority. But in this case, the tailwind increased the aircraft's ground speed, and amplified directional control problem.
Landing into the wind may not have prevented the hard landing, but it would have made maintaining directional control and going around much easier.
Accident 3: 7 Knot Tailwind On AN IFR Approach
A Cessna Turbo 210 was on an RNAV approach in IMC. Based on radar data, the approach was unstabilized from the final approach fix inbound, and the aircraft broke out of the clouds significantly left of the runway.
The pilot made a right turn and maneuvered the aircraft toward the runway. But because of the aircraft's position and the 7-knot tailwind, the pilot touched down approximately half way down the wet runway.
Even though the pilot had 40 degrees of flaps in, they were unable to bring the aircraft to a stop on the remaining portion of the runway.
The aircraft overran the departure end of the runway at approximately 45 knots, and impacted terrain, collapsing the nose gear.
So was tailwind the only factor in this accident? Obviously there were a lot more problems with the approach, but the wind played a crucial role. Had the pilot faced a headwind, and not a tailwind, they would have most likely been able to land earlier on the runway. And had the pilot touched down even half-way down the runway, they may have had enough stopping distance to stay on the pavement. According to Cessna 210 landing performance charts, a 7 knot tailwind increases the aircraft's landing distance by 28%.
Obviously a missed approach would have been the best decision, but by continuing the landing, the tailwind was a major factor in the accident.
The Moral Of The Story: Try To Avoid Tailwind Landings
It's pretty clear that when you land with a tailwind, you're demanding a lot more from yourself as a pilot. Whether it's a long touchdown, increased rollout distance, difficult control on the ground, or a low initial climb performance on go-around, landing with the wind at your back is a lot more challenging, and it takes considerably more space.
In most GA aircraft, landing distance is increased by 10% for every 2 knots of tailwind. That means if you have a 10 knot tailwind, you're facing a 50% increase in landing distance. So the next time you're faced with an option of landing with even a "little" tailwind, take a minute to think about the convenience and time savings, versus the possibility of a problem on landing.
It's acceptable to land with tailwind, and that's why manufacturers provide landing distance data for it. But whenever you can, pick the headwind runway instead. From what we've seen here, the few extra minutes it might take to maneuver and land is worth it.
This is not an original article. It first appeared on boldmethod.com on 28 December 2017. To read the original article click here.
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