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What is: Flying VFR into IMC?

Old 27th Jan 2015, 10:04
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What is: Flying VFR into IMC?

I've seen this around the forum, as well as a number of YouTube videos stating that this is a top killer of Pilots, and I can't really seem to understand what it means.

I know VFR is Visual Flight Rules and IMC is Instrument meteorological conditions, but Google can't seem to provide an answer in Layman's terms, hopefully some of you guys can?
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Old 27th Jan 2015, 10:20
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CM

Put simply.

In VFR flight you look out of the cockpit window and see the horizon and the ground features and use your visual senses to tell you what is what.

In IMC you can't see the ground and have to rely on the instruments to keep you straight and level, on course and at the correct altitude.

This requires learning and knowing to trust your instruments rather than your senses.

As I said, this is simplistic - in VFR flight you still use your instruments to check speed heading and altitude, but you are not reliant on the instruments, whereas in IMC you are.

Flying VFR into IMC is therefore the transition from one to the other, and can result in accidents, especially among those not fully trained/conversant with relying solely on their instruments.
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Old 27th Jan 2015, 10:32
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VFR into IMC

Is something that when you do it for the first time your heartbeat goes up to around 130bpm, your blood pressure goes up and you pray that if you get out of this you'll never put yourself in that situation ever again!

DIVOSH!
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Old 27th Jan 2015, 10:45
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More serious answer

In VFR flight you look out of the cockpit window and see the horizon and the ground features and use your visual senses to tell you what is what.

In IMC you can't see the ground and have to rely on the instruments to keep you straight and level, on course and at the correct altitude.

This requires learning and knowing to trust your instruments rather than your senses.

As I said, this is simplistic - in VFR flight you still use your instruments to check speed heading and altitude, but you are not reliant on the instruments, whereas in IMC you are.
Absolutely! I'd go further and point out that as a VFR pilot you're not aware HOW MUCH you rely on "Blue is UP and Green DOWN" until you lose the reference. Because even when you're looking elsewhere you generally have the horizon somewhere in your field of vision and your brain uses that.

When flying IMC (no autopilot) your resting point for your eyes is on the A/H. You spend no less than 50% of your time looking at the A/H and the rest of the time is spent flicking to another instrument (such as the VSI) and then immediately back to the A/H. At no time would you spend more than a few seconds looking anywhere else but the A/H. This isn't a natural skill and has to be learned by the budding IFR pilot. And, sadly, it's not like riding a bike. It is a perishable skill.

I've read somewhere that the time it takes for the average VFR pilot to enter IMC and completely lose control of his/her aircraft is around 90 seconds.

DIVOSH!
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Old 27th Jan 2015, 11:11
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Could you elaborate furthermore on: "I've read somewhere that the time it takes for the average VFR pilot to enter IMC and completely lose control of his/her aircraft is around 90 seconds."

I don't understand how they lose control from using their visuals, to their instruments!
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Old 27th Jan 2015, 11:20
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Two words

Spatial disorientation.

Google is your friend



Spatial disorientation - Wikipedia, the free encyclopedia
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Old 27th Jan 2015, 11:22
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Mike:
Simply speaking, it's that they value what their senses are telling them over what the instruments are telling them. It's extremely easy to become disoriented when you have no visual reference to the ground/horizon.
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Old 27th Jan 2015, 11:23
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Yep Mike and read the link fully.

All you'll ever need to know to answer your question.
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Old 27th Jan 2015, 11:24
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Actually I believe the theory is roughly 90 seconds for any pilot to completely lose control in IMC if they have zero instruments to rely on. No matter how experienced, the inner ear tells us what we feel, but it may not always be what is happening.

For example, flying straight and level, you feel 1G. That is one times the force of gravity. A shallow banking decending turn also feels 1G, and being completely inverted, pulling slight back pressure and rocketing towards the ground feels the same. Without visual cues, ie. able to see out the window, or have instruments to rely on the pilot has no idea what is actually happening. Hence the accident rate.
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Old 27th Jan 2015, 11:31
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Old 27th Jan 2015, 11:34
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Craviatior,
As a private pilot you are trained to look out of the window at the picture. It's as advertised - Visual.
If you take a visual only pilot and stick them into a cloud, there is a high probability that they will believe whatever their body (inner ear) is telling them. And that will normally induce spacial disorientation.

When I was working on my instrument rating, my instructor took me up, put the hood on, and made me take my hands and feet off the controls.
He spent a matter of 90 seconds turning, climbing, descending and then asked me what attitude the aircraft was in without looking at instruments or outside.
And boy was I wrong. Every time. It's to do with the inner ear and how we balance.

As Di-Vosh says, if you are not an instrument pilot, you will find it very hard to switch from outside the plane to the instruments. Trust me, been there, seen it, done it, changed underwear and prayed to the gods of all things in the air to save me.... And been lucky. Never did that one again.
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Old 27th Jan 2015, 22:15
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Please read the story about the one seat aircraft that crashed at Bulli today to understand the almost inevitable result of VFR into IMC.

VB

http://www.pprune.org/pacific-genera...a-tonight.html
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Old 27th Jan 2015, 22:58
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Could you elaborate furthermore on: "I've read somewhere that the time it takes for the average VFR pilot to enter IMC and completely lose control of his/her aircraft is around 90 seconds."
From the CASA guide that Clearedtoreenter linked,

Spatial disorientation is the big danger. And it can happen a lot faster than you might think just 178 seconds on average, about the length of a commercial on TV .
That estimate is based on studies in the 1990s by aviation researchers at the University of Illinois. They took 20 VFR pilots and got them to fly into IMC in specially programmed flight simulators.
All of the pilots in the study went into graveyard spirals that would have ended in uncontrolled flight into terrain or roll- ercoaster-like oscillations that became so intense that they would have resulted in structural failure of the aircraft.
In repeated tests on the simulator the result was the same all pilots lost control of the aircraft. The outcome differed only in the time required before control was lost which ranged from just 20 seconds to 480 seconds.
It is counter intuitive but very real. Part of ATC refresher training for this scenario involves a tape replay of such an incident. One of the scariest parts was the pilot saying "I think I'm upside down".
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Old 27th Jan 2015, 23:00
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I don't understand how they lose control from using their visuals, to their instruments!
Instrument flying skills are acquired by training and practice. It's not intuitive - in fact quite the opposite.
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Old 27th Jan 2015, 23:02
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It is the mixing of terminology that gets people confused.
RULES and CONDITIONS.

Think of it the way it used to be referred to way back.
Flying in visual meteorological conditions ... You can see where you are going ALL the time, clear of cloud.
And
Instrument meteorological conditions where you can slip into a cloud and see nothing but fog.

Have a go at driving at 40 kph in fog in your car. Wont take long before you hit something and all you are doing is steering in the horizontal plane NOT three...pitch, roll and yaw.

Just trying to keep control of those three axis for the first flying lesson was usually a schemozzle. Most of us could handle two but for me I wondered how the hell I was looking at the bay when I'd started off flying towards the Dandenongs.

Concentrating so hard on keeping the nose on the horizon and wings level was as much as I could do as I very slowly skidded to the right. It was a Tiger Moth which aren't as easy to fly as modern balanced aeroplanes.

Sadly too many people believe that they can get themselves out of cloud when inadvertently going in, but your bum tells lies and you will firmly believe you are in total control because you are pulling positive G force. When the engine is screaming, you are getting buffeted by the unexpected turbulence in cloud you get confused instantly.

Nasty experience to come screaming out the bottom of a cloud at max revs, airspeed needle close to the red, in an attitude you haven't seen since you did unusual attitude training, throws common sense out the window and too many people YANK the controls and break up a perfectly good aeroplane and die.

Since soon after Wilbur and Orville, perhaps tens of thousands of pilots have killed themselves believing they could handle flying in a bit of cloud.

There are enough episodes of air crash investigator on TV showing trained airline pilots from say the north west of us, losing it and not believing their instruments because their bum tells a different story. Not enough practice.

Sadly too many people get a false impression of their flying ability playing flight simulator. Try it with moderate turbulence. Suddenly instruments are jumping.
The problem is, flt sim doesn't have motion which will soon have you confused and ignoring that screaming engine while you concentrate on two axis of flight and think you are going great.
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Old 27th Jan 2015, 23:34
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Quote: Victa Bravo: Please read the story about the one seat aircraft that crashed at Bulli today to understand the almost inevitable result of VFR into IMC.

VB

Lighty down in the Bulli Tops area tonight
Seems we don't need the ATSB on-site as VB has it licked
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Old 27th Jan 2015, 23:43
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CRMike,

This is worth turning the volume up for. Despite the stick we give the regulator (deserved), one of their better efforts here.

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Old 28th Jan 2015, 02:14
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Good onya 7700.

Dribbler!
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Old 28th Jan 2015, 06:55
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Despite the stick we give the regulator (deserved), one of their better efforts here.
Very true Jaba but CASA then disbanded the unit that put this together. So I think the stick is still deserved.
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Old 28th Jan 2015, 08:01
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Back in the old days an RPPL required a minimum of 3 hrs IF training, and a PPL required an additional min. 2 hrs IF training - for a total of min. 5 hrs for the PPL.

Was that enough for a low time non-instrument rated PPL who had flown into IMC to get themselves safely out of the shit?

Well it was for this one!

And then some bright bunny thought it would be a good idea to reduce the requirement.

Dr
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