Как выполнить посадку на лес?

[preacher]

Начал читать тут одну книжечку, буду выкладывать потихоньку.
Первый фрагмент еле разобрал, поэтому выложил перевод, с переводом остального, проблем не возникло.

September 2005 Article of the Month
By Rod Machado
In­flight Emergencies ­ Part 1
How to Crash­land an Airplane

My wife was considering the purchase of a handkerchief for my last birthday
present. Unfortunately she didn't know my nose size. She kids me about this
because my nose size keeps changing. I keep running into solid objects with it.
Several months ago I walked into a door at 2 mph, bounced back and fell on my
derriere. That hurts! Now, my nose is so big that, when I lie down in a sailboat, it
changes direction.
Running into a door at 2 mph is a very uncomfortable experience. It is not,
however, a deadly one. But imagine hitting something solid in your airplane at
100 mph. If a 2 mph collision can swell a nose, a 100 mph collision can
eliminate one.

Pilots sometimes face similar consequences when an engine
failure occurs over inhospitable terrain.
In the event of an engine failure, you typically have several emergency landing
options to choose from. Roads and fields are just a few of the opportunities you
have to make your own impromptu airport. But suppose a reasonable landing
surface isn't available? Suppose you have only trees, rocks or structures to
choose from? How might you handle an emergency landing under these
conditions? As you're about to discover, there is more science than superstition
to this process.
High speed collisions require the dissipation of enormous kinetic energy (energy
associated with motion). This energy varies with the square of the airplane's
speed. Double the speed of impact and you quadruple the amount of energy
involved in the crash. Or, think of it this way. Crashing an airplane at 85 knots is
twice as hazardous as crashing one at 60 knots (Figure 1). The fact is that
speed kills. Knowing how to dissipate energy in a crash is vital to your survival
when forced to land in unfavorable terrain.
Let's explore three simple but very important rules regarding how to crash­land
an airplane under these conditions. We're concerned about dissipating the
kinetic energy and minimizing bodily damage to you and your passengers. The
three rules are shown in Figure 2:

groundspeed determines the amount of energy involved in the impact. You want
to do everything possible to touch down at the slowest possible groundspeed .
Even a small wind can make a big difference in the survivability of a crash
landing. For instance, a 12.5 knot wind makes the difference between a 60 knot
crash and an 85 knot crash. If I'm approaching at 72.5 knots indicated airspeed
and have a 12.5 knot tailwind, my touchdown groundspeed is 85 knots (72.5 +
12.5 = 85). Make a turn into the wind and that 72.5 knot indicated airspeed
becomes a 60 knot groundspeed (72.5 ­ 12.5 = 60). Comparing touchdown
speeds of 85 knots to 60 knots, you can see that landing into the wind (instead
of landing with it) allows you to reduce the impact energy by 50%. (See Figure 1
again.)
If there was ever a good time to use the groundspeed function of a GPS, it's
when you're descending over inhospitable terrain with a failed engine. If you're
going to plant the airplane in rough terrain, you might as well do it as slow as
possible. Assuming you have enough time to do this and assuming your GPS
has a reasonably quick refresh rate, you can make a 360 over the chosen
landing site and monitor groundspeed readings on the way down. The heading
with the lowest groundspeed should factor heavily into your choice for the final
landing direction. Yes, yes, yes, I know, I know. We're talking theory here, but it
can be done (and I'd do it, if possible!).



Род Мачадо
Летные происшествия

Моя жена собиралась приобрести мне носовой платок, в качестве подарка, на мой день рождения. Но к сожалению, она не знала размер моего носа. Она с детьми, говорили мне о том, что размер моего носа постоянно меняется. Это из-за того, что я столкнулся, с твердым предметом на бегу.
Несколько месяцев назад я ударился в дверь, со скоростью в 2 мили / ч, отскочил назад и упал на копчик. Это больно! Теперь, мой нос настолько велик, что, когда я сажусь в парусник, он меняет направление. Столкновение с дверью на 2 мили / ч очень неприятный опыт. Однако это не смертельно. Но представьте себе удар чем-то твердым в самолете, при скорости в 100 миль / ч. Если от столкновения в 2 мили / ч, может опухнуть нос, то при столкновении в 100 миль / ч, нос может просто расплющить в лепешку.

[preacher]

Additionally, keep in mind that surface winds normally shift about 30 degrees to
the left from their direction at 2,000 feet above the ground (Figure 3). Therefore,
if the wind is from 300 degrees at a few thousand feet above the surface,
expect it to blow fromapproximately 270 degrees at the surface. The plain truth
here is that it's worth going to all that trouble to know the wind direction when
it's not obviously apparent. Even a few knots can make a very big difference.
Applying flaps also allows you to reduce the airplane's impact speed. Some
flaps have more of an aerodynamic effect than others. Cessna's Fowler flaps
are very effective in reducing the airplane's stall speed. On the other hand, plain
type flaps don't affect the stall speed as much. Nevertheless, it's probably worth
deploying them anyway.
One consideration to be wary about with flaps concerns how they affect the
airplane's cabin. Figure 4 shows the impact of a Cessna between two trees with
flaps deployed. Notice how the flaps penetrate the passenger seating section of
the cabin. In this situation, if I elected to use flaps and expected to have the
wings absorb the impact, I'd consider having my passengers assume the typical
airline crash position. You know the one I mean. It's where you bend over and
touch your chest to your legs and grab your ankles. This may prevent
passenger injury from flap intrusion into the cockpit. I have a feeling that this
position is also very effective for helping digest airline food, which may explain
why the flight attendant is always trying to get you to look at the emergency information card after boarding. Humm?
Examine your airplane and take into account flap size, flap position and
possible flap movement if the airplane's wings were used to absorb the energy
of impact. If you deem full flaps to be a danger to rear seat passengers, you can
use partial flaps instead of full flaps during an emergency landing. You're the
pilot of your airplane. Decide for yourself what's best for the conditions under
which you fly.

under any circumstance, lose control of your airplane during an emergency
landing. For instance, some pilots think that it's better to stall the airplane onto
the tops of trees (assuming this is their only choice, of course) rather than fly
the airplane directly into the tree tops at slightly above the stall speed. I'd opt for
controlled flight into the trees any day. Here's why.
General aviation airplanes are designed to withstand force from the forward
direction and from underneath the airplane. If the airplane stalls and rolls
inverted (begins to spin) during a tree top landing, the impact energy may be
applied to the top of the airplane as you descend through the trees. There's
very little structural protection provided by the upper portion of the cockpit of
most airplanes. Additionally, seat belts don't work very well in restraining loads
applied in the upward direction. Anyone who's ever hit their head on the roof
during turbulence knows what I mean. Remember, all bets are off if you can't
maintain control of your airplane during an emergency crash landing.
Rule number three requires you to let the airplane and the environment absorb
the energy of impact . The fact is that the human body is pretty resilient. Yet it

 no sense to subject yourself to trauma if you can avoid it. Therefore, our
objective is to minimize the amount of G force we're exposed to during an
emergency crash landing. We can do this by understanding how impact speed
and G force are related.
A pilot traveling at 50 mph who stops in two feet experiences approximately
43G's. The human body can't withstand this amount of force without
experiencing severe or fatal injuries. The same pilot traveling at 50 mph who
stops in five feet pulls only 17G's. This is easily more survivable than a 43G
deceleration. Three feet means the difference between a survivable and
nonsurvivable accident.
The secret to surviving a crash is to let the environment slow you down in such
a way that breakable parts of your airplane (horizontal stabilizer, gear, propeller,
wings, etc.) absorb impact energy. Now you know why returning to the airport
after an engine failure from too low an altitude is very risky. If you stalled and
spun into the ground at 50 mph, you'd probably stop in less than two feet. In
other words, there's probably less than two feet worth of crushable structure
ahead of you. You'll pull over 43G's and get a chest implant to boot (the control
column).
Personally, if I had a choice to stall into the ground or make a controlled crash
into the side of an aluminum warehouse, I'd choose the building. No question
about it (assuming, of course, those were the only two choices). Your job is to
make sure those aren't your only two choices!
Most general aviation airplane cockpits are designed to give each occupant
every reasonable chance of escaping serious injury in a minor crash landing
under the following assumed conditions. First, seat belts and shoulder
harnesses are properly used (more on this in Part 2). Second, the airplane
experiences no more than 9G's worth of linear deceleration in the forward
direction.
The secret to handling the emergency crash landing is deciding how to keep the
deceleration down to 9G's or less. You'll be amazed at how little distance it
takes to decelerate without pulling more than 9G's.

[preacher]

Кто-то хоть читает? Продолжать или нет?

[yatsevsky]

Может лучше ссылку на книжку, не? Или хотя бы полное название на англ. чтобы найти. Спасибо)

[Геннадий Хазан]

Продолжайте. Очень полезная информация

[yatsevsky]

Нашел оригинал - http://www.pdfio.com/k-1807637.html

[лазарь]

Кто-то хоть читает? Продолжать или нет?

Продолжать. Спасибо.

[ded]

«…Разница в направлении ветра на высоте 2000 футов и над землей обычно составляет около 30 градусов. Это важно знать, даже несколько узлов уменьшения скорости дают большую разницу в травмах…
Пилот, двигаясь со скоростью 50 км/ч и остановившись на отрезке 2 фута, испытывает примерно 43 G, получает тяжелые или смертельные травмы. Если  с той же начальной скоростью остановится в пяти футах, то это  17 G, шанс уже есть…
…Секрет выживания в том, чтобы среда замедлила работу таким образом, чтобы части самолета поглотили энергию удара. Теперь Вы знаете, почему возвращаться на аэродром после отказа двигателя на слишком низкой высоте слишком рискованно, т.к. разворот в землю на 50 миль/ч – это остановка менее, чем два фута. Конструкции самолетов разрабатывают так, чтобы перегрузка линейного торможения в прямом направлении составила 9 G и менее. Вы будете удивлены, как мало расстояние замедления в 9 G…».

preacher, конечно, читаем, ждем продолжения. Спасибо за Ваш нелегкий поисковый труд.

[preacher]

Может лучше ссылку на книжку, не? Или хотя бы полное название на англ. чтобы найти. Спасибо)

В посте №15 даны все данные о книге.
И поскольку многие заинтересовались, вот ссылка:
http://www.ultraligero.net/Cursos/cursos_vuelo/tecnicas_aterrizajes_de_emergencia.pdf

Плюс к этому хочу высказать несколько своих мыслей. Подход к выбору сценария аварийной посадки, должен быть сугубо индивидуальным, и отталкиваться от конкретного типа ВС. К примеру большинство "туристических" ЛА имеют 2-3 класс прочности, а большинство пассажирских аж 5, ну и множество других особенностей.
Еще пример, если низкоплан садится на грунт, с выпущенными закрылками, - какова вероятность, что ударившись ими о землю, ВС получит дополнительный импульс к зарыванию носа, и быстрой остановке, с вытекающими?
Почему так много свалов было при аварийных, - как много пилотов, четко помнят скорость сваливания своего ВС, но без выпуска закрылков?

[Горелов]

... При посадке да воду, минимальна опасность возгорания, и сама посадка мягче, что и дает возможность остаться при сознании и покинуть ВС после приземления (пардон приводнения).

прменимо только для самолетов с убирающимся шасси.

[Горелов]

Почему так много свалов было при аварийных, - как много пилотов, четко помнят скорость сваливания своего ВС, но без выпуска закрылков?

мало кто начал свой летный путь с планера. отсюда - ошибки в расчете захода без двигателя, желание дотянуть (перетянуть препятствие) и сваливание.

[preacher]

прменимо только для самолетов с убирающимся шасси.

А если не убирающееся, а кругом вода - что лучше кувырком, или целенаправлено вверх брюхом? Хотя конечно если летать, там где кругом вода, то поплавки существенно лучше.

[Геннадий Хазан]

Если кругом вода то кувырком НЕ лучше! Уже раза четыре эту тему обсуждали.

[AVIATIK]

Один раз довелось на мотодельте садиться на заброшенный сад,
практически лес,все закончилось благополучно.Конечная точкой
касания была яблоня, которую разложили пополам.Выбрались с
товарищем с мотодельты, отряхнулись,посмотрели назад,а за нами
просека.В такой ситуации, я думаю, лучше было завесить аппарат
и свалить на крыло.

[Тэги:]

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