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Takeoffs and climbs are as deadly as approaches, descends and landings - What can we do about it?

Corrected

Administrator
Shoreham EGKA, United Kingdom

It seems to me that Vx is really quit low on most of types

For propeller aircraft it is quite close to Vs1, around 1.1-1.2x and in some types very close – eg 45 mph IAS in the 150 HP Super Cub with flaps extended, Vs1 is only 43 mph.

Oxford (EGTK), United Kingdom

Peter wrote:

Probably another reason for takeoff accidents is that any overweight condition is present there, whereas it will be very unlikely to exist on landing. And lots of people fly overweight as normal practice

I have a feeling that this sums up a big part of the take-off accidents. Some people seemingly have never heard of W&B calculations, let alone know how to do them. And some types have surprisingly little useful load. This can bite especially if a sub-type is significantly different from the rest of the fleet.

I don’t know. Statistics is just that. Flying a SEP is a risky business (according to statistics), and drilling down to the details doesn’t necessarily show anything but the details of the statistics. There has to be some causes for that risk, but that doesn’t necessarily mean each actual individual cause really is all that interesting.

I mean, we have walked into this with open eyes, knowing what the risks are and the cumulative magnitude. Human error is a rather random process, it can happen at any time and is usually caused by a mix of simple ordinary things (small distractions, over confidence in one self and the equipment, complacency, poor stick and rudder skills, “won’t happen to me-ism” and all sorts of other stuff). So, in phases where the stick and rudder skills are of more importance, is also where you find most of the accidents that shows lack of this skills and so on. Mix that with a small distraction, a piece of over confidence and a dash of complacency, and you have a nice soup that makes up the statistics.

To handle that soup only two things are needed:

  • Airmanship
  • Flying skills

More focus on that is the only thing that will improve the statistics. IMO the key is to fly in such a way that enables you to have a plan B at all times (airmanship). To do that you also need to know the limitations of your flying skills, and fly inside that envelope with some margin. To do that you need to know that margin, both skill vise, but also mentally, how much can you handle before your thought process is saturated – and act correct when that happens.

One more thing. I read about drones (fighter aircraft drones) the other day. Statistics from wars show that only 5% of fighter pilots were responsible for 50% of the enemy kills. Which is the main reason to use drones instead of pilots in fighter aircraft. Similar, the statistics for GA accidents may show a similar relation. Only a small percentage of pilots are actually responsible for the majority of accidents, only there is no way of knowing. It may also show that 5% of us is not in particular risk of accidents, but there is no way of knowing that either. I believe the former is the more correct.

Last Edited by LeSving at 17 Jul 07:34
The elephant is the circulation
ENVA ENOP ENMO, Norway

RobertL18C wrote:

45 mph IAS in the 150 HP Super Cub with flaps extended, Vs1 is only 43 mph.

But of course Vs is effectively more than 43 mph at full power

Darley Moor, Gamston (UK)

It is horribly misunderstood, and not at all trained that fixed wing aircraft, like helicopters, have a “height/velocity” or “avoid” curve. For every helicopter, it is presented in the flight manual, and type training requires understanding it. It is the combination of airspeed, and height above the ground, slower or lower than which, a safe gliding/autorotating return to landing is not possible. Every fixed wing aircraft, even multi engined, can be flown so slowly, that a loss of altitude will be required to accelerate to a safe gliding speed. And the “best glide” speed presented in the flight manual may not be that speed, it may be faster. “Best glide” might get you to the field, but does it allow you the reserve of speed you would like to have to spend arresting your descent rate prior to touchdown (the flare)? Maybe not so much for the unpracticed.

I see those horrifying “STOL” takeoffs, apparently customary at the Valdez Alaska competition, and it worries me when pilots go out to do that with no good reason. Sure, it’s fun to get your aircraft off the surface in the least distance, but then for safety, remain in ground effect, and accelerate to a safe climb away speed, rather than hanging on the prop up to a few hundred feet. If these silly pilots have an engine stop while climbing away at slower than Vx, they’ll be on the ground before attaining gliding speed, with a reserve to flare.

And, when comparing to a helicopter, In addition to having altitude to spend, it can store a reserve of energy for flare as both excess airspeed, and rotor RPM – the fixed wing can store it only as airspeed. Fail to attain that, or waste it, and a crash is certain. I rarely see approaches flown slower than Vx, so why fly a departure that way? Yes, if there’s an obstacle, slow to climb over it – you’re taking your chances in that segment of flight, but then accelerate so you can store energy.

If pilots were actually practicing low altitude EFATO’s they would soon scare themselves into learning this. I’ve done the required flight testing, and it’s scary!

Home runway, in central Ontario, Canada, Canada

Pilot_DAR wrote:

If pilots were actually practicing low altitude EFATO’s they would soon scare themselves into learning this. I’ve done the required flight testing, and it’s scary!

I guess with some bounces or jerky pull on the stick, you can still take-off well bellow Vx, Vs1 or even Vs0 due to vertical accelerations while hanging it on the prop and ground effect but for it to end-up well is once acceleration is dampens you should end up with V>Vs0

To sum up all those equations, you can only make it out alive by simple luck as you have to deal with:
- Free-fall mechanics that mix speed, height and power (V = function of hight, power)
- Ground effects that mixes speed and height (Vs0 > V > Vge = function of height, AoA and speed)
- Smooth transition to free-flight where height does not matter (V > Vs0 = function of AoA)

Even if speed is 20kts, you would not call it a “stall” as AoA is always way bellow its critical values with ground effect and the airflow does stay laminar behind, it is just you can’t cross the Vs0 wall without hitting the ground never mind best glide Vbg (similar to the other way around, without low Gs you can’t fly bellow Vs0 without stalling)

You only appreciate that slow flight bellow Vs0 stall speed on under-powered types (e.g. 30hp ) as the only way to takeoff without PIOs is to do nothing for a long time, otherwise you have the impression that your elevator has been mis-rigged in the opposite way….

Last Edited by Ibra at 17 Jul 22:29
Paris/Essex, France/UK, United Kingdom

fabian wrote:

After a very recent tragic accident during takeoff, involving the plane I used to fly the most,

The french registered 172 at LOAV? I saw that one in the papers… any idea what happened? The pictures were rather puzzling, looks like they went in with an alarming pitch down attitude.

fabian wrote:

What can I do to avoid these dangers, what can we all do?

Any take off needs to be planned as much (or even more so) than any landing. Performance must be checked and re-checked, W&B, Density Altitude, ground roll distance, distance over 50 ft, climb out data. V-Speeds must be briefed and be present. Take Off abort criteria need to be defined and adhered to. Scenarios need to be developed in case of EFATO: where will I be able to land when it happens along the flight path of the initial climb.

Clearly, there are riskier and less risky take offs. Taking off on a 3000m runway will leve a lot more options than taking off on one which hardly exceeds the 50 ft distance or even does not reach it.

fabian wrote:

Speaking of rotation speeds, I know there are many people who aren’t fans of using those in small GA planes, but maybe a very premature rotation or a delayed one would be immediate cause for alarm and an aborted takeoff.

People who don’t use V-Speeds even on very small airplanes are giving away performance and safety all at once. What speaks against it? Nothing really, but there is a lot to be said for using them.

When I started flying on C150’s I was taught to “relieve the load of the nose wheel” early and to wait for it to fly off the runway. That was ok on the runway at Altenrhein, where you had 1300m of concrete. It also worked sort of with the school plane we had, as the prop was configured for climb, consequently the airplane was slow enroute. When I got my own plane after my license, it had a cruise prop and take offs became a stressful thing, that airplane simply glued to the runway for much too long. Why? Because with this technique of lifting the nose wheel too early, it never had the chance to accelerate at a normal rate.

I then went for my IR and CPL on first a Baron and then the Seneca II, both of which were operated using Vr. As I commuted from and to Bern with my C150, after the fist Baron Session I thought, why not try this with the Cessna. A re-read of the POH talked of lifting the nosewheel at 55 mph, which incidently is the Vs at zero flaps. For some reason we always took off at flaps 10 for which there are no figures, but for flaps 25 Vs straight is 49 mph. So with Flaps 10, a Vr of 55mph sounded reasonable. And it worked: gone was the ground hugger, this airplane leapt of the ground positively.

Later I learnt that Vr usually is calculated as Vs * 1.1 and V2 as Vs * 1.2. That is what I keep doing today in the Mooney and it corresponds pretty closely to the figures the POH suggests. POH figure for rotation is 65-75 mph as described in the take off section with a Vx of 80 mph and Vy of 105 mph. At Gross Weight, Vs with flaps 15° is indicated at 64 mph, so Vr would be roughly 70 mph using the 1.1 factor.

And these things were not even a very old science: the need to adhere to Vr came with the first jets, particularly the Comet. When a comet crashed at Rome Ciampino by simply refusing to get airborne, it was found that the crew had followed the old moniker of unloading the nosewheel to such an effect that the drag they created overcame the airplane’s capability to accelerate. Yep, same thing… same aerodynamic.

So quite a few POH’s will not indicate any specific Vr, but all of them do indicate Vs, consequently it is easy enough to figure out what Vr should be.

Obviously unloading the nosewheel can be important on rough surfaces and on soft fields, but then don’t expect to get book values for a dry hard runway! Increments are indicated in the POH if you are lucky.

After unstick, Vx to clear obstacles and Vy thereafter should be 2nd nature.

As for how to define an abortion speed, V1 per se does not really make sense for a single, as the actual abort criteria for anything but an engine failure would be the time when the airplane lifts off. Even after that, runway lenght permitting, a reland is not impossible but requires quite fast reactions. Almost no SEP however gives an indication of accelerate and stop distance (ASDA), which would be the distance to accelerate to Vr and then stop the plane again.

Some people I know work it this way: Use the ground roll distance for take off from the POH and add the ground roll for landing with the same conditions and add a factor for the time you need to initiate abort at Vr. So e.g. for the C150 at MTOW on a standard day at 2500 ft DA this would give 910 ft to lift off and 470 ft to stop, so a total of 1380 ft (420m) plus say 20% reserve would mean a minimum runway lenght of 500m . For the Mooney, same conditions, roll for take off is 1030 ft and landing ground roll is 640 ft which results in 1670 ft (510m) plus 20% means about 610m . Calculating this ASDA like this gives a good indication if not a guarantee but it is better than nothing. Commercial air transport often use a factor of 1.6 to define the minimal runway lenght.

Of course this is not binding and you have to calculate it for each take off, unless you make yourself a nice excel sheet where you put your take off calcs in or even more sophisticated program it into a small app where you then can enter the conditions.

WnB is a huge issue, granted. Lots of people fly overweight all the time. As a former load controller for passenger and cargo planes i never understood how they can do that. Granted, WnB used to be complicated to do in the old paper days, not anymore, anyone with mediocre Excel knowledge can make a sheet where you can enter the figures in 2 minutes. Flying overweight is not only illegal it’s dangerous. Flying out of balance is deadly.

MedEwok wrote:

Personally I always feel uncomfortable when take off is performed at relatively low speeds, such a Vx or Vy. These speeds give little to no reserves in case of gusts or a sudden loss of engine power. Also climbing with a higher speed is much more comfortable due to less nose-up attitude.

It is always a case of weighing performance needs vs operational desirability. Most people do indeed climb in a cruise climb configuration for the reasons you indicate. This does work well enough but you need to take into account that doing that will change your performance envelope. That is why it is very important to understand what figures e.g. the time-fuel-distance to climb graphs take into account. Mooney for instance is a perfect example how a POH opens more questions than answers so I use that as an example.

In the operating section, they indicate correctly the Vy=80mph and Vy=105 mph values (which obviously change with altitude) but then go on to say “for increased visibility and cooling” you should climb at 115-120 mph IAS. It is also mentioned you should retract the flaps. In the performance section, you can’t find a time-fuel-distance table but only a rate of climb table which (big surprise) indicates climb with Flaps 15 and a Vy which decreases from 105 mph at sea level to about 80 mph at 20k ft (IAS). So how can you plan a flight with that?

The answer is, you can’t really unless you go and test fly it and gain experience. 115 – 120 mph IAS are fine in low altitude, but obviously the higher you climb, flying IAS will increase TAS but it won’t help you to climb, it may in fact stop you from reaching the indicated service ceiling. So in order to get yourself a TFD table for climb, all you can really do is test fly it as the information in the POH is useless for practical flight, or find someone who has done it. As our planes are not around since yesterday, most of them have been calculated to death in the user groups. In my case, I did find a table done by Bob Kromer, former test pilot and CEO, which gave a good indication on what a constant IAS climb will do and I did some verifications myself. What I came up with is a climb procedure which will start at 120 mph and gradually reduce to 100 mph above 10’000 ft, which will get me to 10’000 ft in about 15 minutes at max gross and to 17000 ft in about 30 minutes. Fuel flow and TAS calcs will give you an approximate fuel and distance for this exercise or rather check your totalizer at top of climb. After a few climbs, you’ll know what to put into your performance calculator.

Bottom line, the more you know about your airplane, it’s speeds and limitations, the less you will risk ending up in a situation where you run out of runway, altitude, power and ideas. And messing around with figures in excel is actually fun.

Last Edited by Mooney_Driver at 17 Jul 22:54
LSZH(work) LSZF (GA base), Switzerland

For Cessna tricycle planes I fly, I will hold the nosewheel at least light, if not full up elevator, relaxing as needed as the speed increases. Three reasons: It reduces wear and tear on the nosewheel/strut/steering, allows the rudder to affect directional control, rather than nosewheel steering, and keeps the prop up out of loose surfaces as much as possible. Only for the most short takeoffs, will I allow much weight to remain on the nosewheel. Yes, the difference between a climb prop (48" pitch) and a cruise prop (52" pitch") on a C 150 will make a noticeable difference in takeoff performance (and endurance!). Funny that the POH for the 150 really never says which prop is on the plane for which performance figures were published!

Yes, there will be aerodynamic drag resulting from the up elevator. For all operations with Cessnas out of normal length runways, it’s not enough drag to change the outcome of the takeoff. Worn out nose struts are expensive to repair. I’m a bit more cautious with Cherokees, and Tomahawks. Tomahawks tend to have the tail become effective rather suddenly, so nose up elevator held early can surprise you, and initiate a PIO. Cherokee’s stabilators tend to develop a lot of drag when deflected full up. Heavy, on a hot day, you can get a Cherokee stuck in ground effect if you force the aircraft into the air too early. I’ll still keep the nose light, but that’s all, I minimize soft field technique when flying Cherokees.

Some types I have flown (Bellanca Viking, Twin Comanche come to mind) will wheelbarrow if pitch up control is not applied during acceleration. They can start runway excursions something like a ground loop if the nosewheel takes too much weight during takeoff. It is helpful to get to know your type, and get type training for odd types if possible.

Home runway, in central Ontario, Canada, Canada

Pilot_DAR wrote:

It reduces wear and tear on the nosewheel/strut/steering,

Quite valid, my 150 did have recurring shimmy damper issues.

To be clear, i did not apply forward yoke like you would on a jet, but simply kept it neutral or slightly up. The way I was taught originally was, as you also suggest, full elevator up. That however in the C150 I flew had the effect that ground roll went way past book figures, sometimes double the ground roll figure.

Pilot_DAR wrote:

Funny that the POH for the 150 really never says which prop is on the plane for which performance figures were published!

LOL, very true. I sometimes get the idea that they took whichever prop was yielding best results. Most of the performance figures were science fiction…. particularly the range. I wonder how many C150’s have landed before the intended destination because they looked at those figures.

Pilot_DAR wrote:

Some types I have flown (Bellanca Viking, Twin Comanche come to mind) will wheelbarrow if pitch up control is not applied during acceleration.

I believe the Twin Commanche has an STC for a smaller diameter nosewheel to counter that trend.

Pilot_DAR wrote:

It is helpful to get to know your type, and get type training for odd types if possible.

Absolutely. My attitude is that you can never know enough about the type you are flying. Sometimes I despair with people who will only read the POH properly once they actually have flown the plane and wonder why it doesn’t do what they expect it to. Whenever I get to fly a new type, I will get the POH first and read it cover to cover and play with the figures. Admittedly, that sometimes is enough to forget about certain types but mostly it will give the best preparation for actually flying it.

LSZH(work) LSZF (GA base), Switzerland
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