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Hovering whats?


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Something I was thinking about recently (based on this comment on wikiRFM) is the importance of using the right terminology. So, even though we all call that thing we're supposed to do when the engine quits in a hover a "hover auto", is that the right term? Why or why not? Does it matter what we call it?

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It seems as if there are a lot of improper aviation terms, Coriolis, ground effect being a cushion of air, but I feel like the FAA and DPE's have to be the ones who change the terms.

 

 

I have some questions about the maneuver though.

 

There is a comment in your link about not doing them to grass, yet at the Robinson school they are done on the grass.

 

Also, is it worth the risk to practice hover autos with forward movement or surprise autos?

 

What are the upward limits for common aircraft. I've done them above hover height in a high-inertia helicopter, I assume this is not a good idea in a Robinson?

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Hover Autorotation is not really the correct term but it's accepted. Not correct becuase there just isn't enough time for any upward flow of air into the rotor system in which to drive the main rotor. That which is the definition of an autorotation.

 

Why not do them in the grass? Not much of a problem. I suspect though the concern being pointed out is that there is a bigger risk of roll over if the pilot allows the helicopter to drift enough.

 

I taught "hover autos" with forward movement all the time. While going into parking. Of course I made sure to have a smooth surface to allow the slide. The thing this teaches the student is to avoid the aft cyclic movment that is second nature to want to do. Reason being, you can hit the tail boom if you do so. This is true for full down autos as well.

 

I had CFIs mad at me for doing them, I've had them mad for me demonstrating and teaching autos including 180's at night. There is more of a risk I suppose but with a CFI who has the expierence to do them and a student already able to do autos I don't see much of an issue.

 

With the R-22 it is better for CFI's to err on the side of caution. It's such a light weight system. Even though HV curve starts at 10' in a hover it's a work out to do a "hover auto" from that height.

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Pertaining to the not doing them in grass comment....I'm not sure as to the accuracy of it (however it makes sense) the reason I was taught to never do them to grass is that most students (initially) will still have some sort of movement, twisting movement, and the airframe was not designed to handle that stress....Also, when it goes wrong, which to a certain extent it will, and you hit harder than you'd like on grass the skids won't flex, on a hard surface the skids flex out absorbing some of the impact. That's what I was taught and to me it makes sense.

 

And when I say skids flex I mean the cross tubes....I'm not sure if any of this pertains to the 300 with dampers on the skids.

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When I went to fly a 500 once, the Cfi regaled a story to me about another pilot transitioning into one. It seems on approach the RPM had gotten a little low. The Cfi said “add power”, the student “raised the collective!” :o This went on a few times, until the 500 hit the ground hard, pan caking the skids.

 

From my experience I reckoned that the Cfi must have trained in the 300 (where “add power” means “increase throttle”) :mellow: . The student, however, was obviously a Robbie Pilot, where “add power” means “up collective”. :huh:

 

With low RPM the term, “add power”, can produce two completely different results, depending on to whom you are speaking, (especially if they’re not checking the Tach! <_<

 

Beware of your terminology! :)

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It's called a hovering auto because it's initiated from a hover. Whether or not the rotor system ever gets into a complete autorotation is just nitpicking. It might, or might not, and it's entirely immaterial, because the pilot actions are the same regardless. Sometimes it's just a waste of time trying to be too precise, and sometimes close enough is good enough.

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Gomer said ,"it's entirely immaterial, because the pilot actions are the same regardless. "

 

Sorry, mate, but the actions are completely different. The pilot freezes the collective, allows it to sink, then cushions on. He definitely doesn't fully lower the lever and flare for 60kt.

 

That's why in our schools the terminology is "Engine Failure at the Hover " (EFATH) precisely so that the dopey student doesn't associate it with an airborne auto and dump the lever. :blink:

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I'm pretty sure the referral to the pilots actions being the same is in reference to whatever name that the maneuver is called, not differences between an autorotation at altitude vs whatever it is called when the engine poops at a hover.

 

As a wise man once said,

 

"What's in a name? That which we call a rose

By any other name would smell as sweet."

 

 

Romeo and Juliet (II, ii, 1-2)

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I think we should start referring to it as a "Hovering needle split"

 

:lol:

 

Or..

 

The maneuver completed at a hover where a passenger can actually hear the pilot crap their pants before they can smell it.

 

But, that is a lot to say every time it is practiced.

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I have taught "hover autos', "engine failures in the hover" or whatever name you want to call them in the grass, in forward movement and on tarmac. Don't see why not because when it happens, chances are it won't be in ideal conditions.

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That's why in our schools the terminology is "Engine Failure at the Hover " (EFATH) precisely so that the dopey student doesn't associate it with an airborne auto and dump the lever. :blink:

 

I've had that happen. Student had been doing straight-ins, then we did some "simulated engine failures while hovering". He lowered the collective and I grabbed it just before we contacted the ground... Thankfully it ended well and was nothing more than a good lesson for both of us. I now ALWAYS have a discussion about which way they are going to move the collective, prior to practicing simulated engine failures while hovering.

 

Another maneuver I ALWAYS talk through with a student imediately prior to practicing is low RPM recovery. I have them physically raise their hand and show me which way they will roll the throttle during low RPM recovery.

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I've had that happen. Student had been doing straight-ins, then we did some "simulated engine failures while hovering". He lowered the collective and I grabbed it just before we contacted the ground... Thankfully it ended well and was nothing more than a good lesson for both of us. I now ALWAYS have a discussion about which way they are going to move the collective, prior to practicing simulated engine failures while hovering.

 

Another maneuver I ALWAYS talk through with a student imediately prior to practicing is low RPM recovery. I have them physically raise their hand and show me which way they will roll the throttle during low RPM recovery.

 

i either was advised or read somewhere (can't remember which one) to avoid hover autos and autos at altitude in the same lesson for exactly that reason.

 

I do emphasize avoid because sometimes it is necessary because they are both done during checkrides.

 

Our examiners/inspectors typically will space the maneuvers out as far as possible during the checkride.

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In Canada the term "hover auto" is not recognized. It is identified as an engine failure at the hover. Below is the exercise straight from the Transport Canada Helicopter Instructor Manual.

 

 

EXERCISE 11

86

ENGINE FAILURE AT THE

HOVER/HOVER TAXI

GROUND SCHOOL POINTS

Flight Manual - Height Velocity Chart

----------------------------------------------------------------

PREPARATORY INSTRUCTION

Aim

For the student to learn how to land safely following an engine failure at the hover or hover taxi.

Review

Exercise 9 - Hovering

10 - Take-off/Landing

Motivation

Engines can fail just as easily at the hover/hover-taxi as in flight. The helicopter will land very quickly should this

happen and it is vital that the pilot can react quickly and prevent an incident from becoming an expensive accident.

Airmanship

Selection of suitable area for practice.

Teaching Points

(1) Point out that at normal hover/hover-taxi heights, it will not be possible for the pilot to enter autorotation.

In fact, lowering the collective following an engine failure, will result in a heavy landing. This manoeuvre

should not be considered an autorotation, the pilot relies on the inertia in the rotor system to land safely.

(2) Describe the reaction of the helicopter when the engine fails:

(a) yaw (to the left in American aircraft);

(B) drift (to the left in American aircraft) and to the rear; and

© sink.

(3) Explain that the yaw and drift must be corrected before touch-down. Sink should be controlled by use of

the collective as appropriate to type of aircraft and height above ground, to cushion the landing.

(4) Explain that should the failure occur at the hover taxi, the pilot should avoid any rearward movement of the

cyclic, and accept a run-on landing.

Confirmation

PRE FLIGHT BRIEFING

EXERCISE 11

87

AIR LESSON

(1) Engine Failure at the Hover

(a) Demonstrate into wind as follows:

(i) verbal warning;

(ii) close throttle;

(iii) counteract yaw and drift; and

(iv) cushion landing.

(B) Student practice

(2) Engine Failure at the Hover Taxi

(a) Demonstrate into wind.

(B) Student practice.

POST FLIGHT DEBRIEFING

TIPS FOR INSTRUCTORS

(1) This exercise should be introduced by providing the student with plenty of warning before each practice.

The manoeuvre can then be speeded-up to flight test standards where the student is given minimal warning

of the practice engine failure.

(2) Closing the throttle and cushioning the landing with the collective takes a good deal of manual dexterity in

most helicopters. Since the aim of this exercise is for the student to react to an engine failure, there is little

point in his learning throttle control, in other words the instructor should control the throttle.

(3) Tail-rotor failure at the hover/hover-taxi, which does require coordinated use of the throttle and collective

by the student should be practiced at a later stage in training.

(4) Always ensure that the surface is suitable for this exercise, particularly after precipitation.

(5) This is a good exercise to demonstrate to the student the landing stage of an autorotation. It is a good skill

to practise just before starting a full-on autorotation exercise.

(6) Exercise caution as a student may react to a simulated engine failure by rapidly lowering the collective. Be

sure to state a verbal warning before closing the throttle.

(7) The demonstration of this exercise is easily split to show the three control movements separately, do three

separate demos letting the student focus each time on an individual control movement, then combine all

three before student practise.

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  • 2 weeks later...

in regards to responding the same as a simulated engine failure during flight, my stick buddy did just that on his first "hovering auto". IP didn't catch it in time, though. We hit pretty hard. (Much like doing a deck landing, but with a much faster collective reduction...I think between my stick buddy and myself, we took some years off that old fella's life. I can't wait until I become an IP and someone gets to extract revenge for him. lol)

 

WhistlerPilot: I find it amusing that your lesson plan there advises a slow methodology to doing autos (i.e. individual control movements during "EFATH", like learning to hover, and THEN standard autos). I didn't do "EFATH" until several days after I had been doing standard autos. I guess the Army does things a little bit differently.

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