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SupremoUser is Offline
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10/08/2010 8:45 AM  
Perhaps we can get going with some specific student questions? Quick Stop was the term used years ago and now its an oxymoron, rapid deceleration. For the new pilot in rotorcraft it can be a lot of information and control inputs without really knowing why you are doing it? It teaches the pilot how to plan ahead of the event even if its rapid fire and done without much concious thought. Difficult at first and then becomes a fun maneuver as you learn to flare like a duck coming to land on water! With helicopters you certainly don't want to tilt the axis of the machine to the point you get a tail strike. There are some very rapid changes that take place as you begin the flare with aft cyclic lowered collective, watching rpms, pedal pressure forward cyclic pulling collective pedal pressure and rpm to get to a hover. I just sat here trying to chair fly it while typing and may have got some out of order but its hard to type and fly! This is a maneuver that is common to ag operations and we did it/do it many times daily. To watch an ag pilot in a helicopter is to watch someone work the machine rather than just fly it. I have many thousands of hours in helicopters and a lot of it instructing but even more doing utility work in which I worked the helicopter often to its limits. Looking forward to more inputs from the pros and students alike. Semper Fi

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10/08/2010 12:20 PM  
Supremo's first point is worth repeating since what the maneuver is called frames it for the student. The "Quick Stop" is really neither quick nor a stop, hence the oxymoron label. Rapid Deceleration, or, from an instructional perspective, Control Coordination Exercise are much more accurate terms.

The reason I like "Control Coordination Exercise" is that it better fits the maneuver into the continuum between the student being able to coordinate the controls under fairly stable flight conditions (climbs & descents or take offs) and conditions where larger control inputs--and therefore more control coordination--are used (max performance take offs and autos).

The way I was taught it was to level-lower collective-flare-level and descend. This was taught as an Air Taxi/Quick Stop maneuver, but it's components are are a stepping stone to autorotations (including the same sight picture for the flare). Instead of making that connection though, that school's philosophy was to use it as a "quick stop", and the next step was that you'd be air taxiing somewhere and your instructor would start saying "wires...wires...wires..." (Which elicited reactions other than those desired usually.) I get the idea (it's the same way they'd do engine out/forced landing training) but completely misses what I think of as the main value of the maneuver. Supremo brings in something that I missed having trained under that philosophy: you can also throw in monitoring the RPMs, which provides an additional stepping stone to doing a good auto.

Anyway, those are my thoughts on it. If you haven't noticed, I run a web site to share and refine teaching techniques, and I've set up a page just for this topic.

Also, I'll throw in my practical application for the RD since it is a fun maneuver that you'll really use outside of flight training. This summer I flew with BoatPix for a few weekends, and the RD is all part of the routine. Catch up to a boat, RD, circle it, scoot on to the next. It's never a quick stop, but a very smooth, controlled maneuver that you use to position the aircraft. Finesse is key, since the Mariners we were flying are especially sensitive to being out of trim at high speed because of the big ol' floats they have on the skids.

dempdUser is Offline
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10/08/2010 2:24 PM  
Posted By kodoz on 10/08/2010 12:20 PM
Supremo's first point is worth repeating since what the maneuver is called frames it for the student. The "Quick Stop" is really neither quick nor a stop, hence the oxymoron label... 

 ...It's never a quick stop, but a very smooth, controlled maneuver that you use to position the aircraft. Finesse is key, since the Mariners we were flying are especially sensitive to being out of trim at high speed because of the big ol' floats they have on the skids.


When I learned the "Quick Stop" it was quick, and we did stop!  The point of the maneuver is to avoid an unexpected obstacle, therefore you need to stop, quickly!  That is how I did the maneuver for the DPE (a seasoned veteran), and that's how I still do it today (when practicing).


However, these days, whenever I fly with a Cfi (for recurrent training, BFR, or whatever), they say I'm too abrupt, and insist that I "slow it down".  That maneuver is fine (I use it whenever I end an Air Taxi), but it is not a "Quick Stop"!


These are two seperate maneuvers (albeit very similar), and should be taught seperately.  You can call one a "coordinated repositioning, or slow down", but don't rob us of the actual "Quick Stop"!  Its my favorite maneuver!


By the way, I get your comment on the Mariners.  Having flown with Boatpix, I know.  At about 75kts the nose likes to "tuck under", due to the floats.  Still,... fun flying!
 
SupremoUser is Offline
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10/08/2010 4:10 PM  
If the "quick stop"i used for avoiding running into an obstacle, someone isn't planning far enough ahead! that is not to say something can't pop up in front of you requiring some fancy maneuvering to avoid. But, I would think a turn or pullup is more apropos rather than stopping in front of the obstacle. Certainly there are many different scenarios and none of us can lay out all of the potentials.
The "Quick Stop" or "Rapid Deceleration" is more of a coordination effort for training in this context. To be sure, we use them on a daily basis and sometimes in an "abrupt" or more severe attitude, but that is usually because we weren't paying attention to wind or ??? and got behind it.
With more than 9K hours in rotorcraft and more than 13K in ag operations I'm quite familiar with the lower reaches of the airspace system and max performance required as daily ops.
Nothing is cast in concrete except death and taxes. Flight is a constantly changing environment and the alert pilots are adapting to it on a minute to minute basis. Just as a minor point, fuel burn changing the weight in flight? Constant change requiring constant inputs and adjustments.
The quick stop maneuver is just one of many for rotor pilots to learn and practice. I enjoy doing them but after a 10-12 hour flight hour day they get raggedy after doing them 40-50 times to a precision landing on a truck or to a loading pad.

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dempdUser is Offline
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10/08/2010 5:05 PM  

This is how I set it up in my lesson plans;

Quick Stop:

Fly along the taxiway.  Just before reaching an intersection, say "quick stop".  The student "quickly", and "abruptly", "jams on the brakes"!  The point being to stop just before reaching the intersection.  (20-25ft / 40kts) (similar to a takeoff run)

 

Slow Down:

Initiate an Air Taxi to a specific point (compass rose, helipad, etc.).  Then slowely "tap the brakes" to transition from flight to a hover just above the LZ.           (50ft / 55kts)

Both of these maneuvers require the same coordination of the controls.  The "Quick Stop" is just done faster, and more abruptly.  I wouldn't call the transition to land on a cart, or truck a "Quick Stop".  But, then again, we're all pilots, and we can call these maneuvers whatever we want. 
 

Trans LiftUser is Offline
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10/08/2010 5:38 PM  
I have to disagree Dempd. I think the Quick stop, Rapid Decel of whatever you chose to call it, is a co-ordination maneuver. Yes it can be put to use in the real world but the point of the maneuver is co-ordination. If you can do it slowly and controlled without gaining or losing altitude, then you can do it fast if you have to. I would be more impressed with a student who can do it in a slow, controlled manner than abruptly.

JAA and FAA have different techniques to perform the maneuver too. The FAA want you to slow to a sufficient speed and then descend to a hover without stopping. The JAA like you to stop the aircraft, pause and then decend to a hover. The difference being the pause before the descent, supposedly to stop you from settling. They do them at 70 kts too. We also do downwind quick-stops on the JAA Commercial course too and are examined on them. Again a controlled maneuver starting on a downwind leg (low level), initiating flare and turn simultaneously (30 degree bank) to bring the aircraft around into the wind. You don't want to be too abrupt in this one.

I would call a transition to land on a truck or cart a quick-stop, especially when you are decelerating rapidly followed by the descent and a landing. In the ag world yo don't alway s have time to slow up and make a nice little approach, time is money!
iMac__User is Offline
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10/09/2010 2:46 AM  
Posted By dempd on 10/08/2010 5:05 PM

This is how I set it up in my lesson plans;

Quick Stop:

Fly along the taxiway.  Just before reaching an intersection, say "quick stop".  The student "quickly", and "abruptly", "jams on the brakes"!  The point being to stop just before reaching the intersection.  (20-25ft / 40kts) (similar to a takeoff run)


In the teaching environment we should all be cautious of the words we use and how they maybe misunderstood. You’re correct in that the Quick Stop can be preformed with a quick and/or rapid cyclic application. That would then require an equally rapid application of collective and pedal to maintain coordination. The Quick Stop, in any case, is still preformed with smoothness and coordination.

 

There should never be any abrupt control movements, except in case of emergency. Abruptness is a sudden unexpected (unplanned) action lacking continuity.

http://www.youtube.com/watch?v=Z1rJ34kl0oo&feature=related

 

Lets define the terms:

 

Quick:

Moving fast or doing something in a short time; prompt; happening with little or no delay.

 

Rapid:

Happening in a short time or at a fast pace; characterized by great speed.

 

Abrupt:

Sudden and unexpected; not flowing smoothly; disjointed; lacking smoothness or continuity.

 

 

The FAA’s PTS sets the standard for training and testing in the U.S. As such, the PTS references the standards for the Rapid Deceleration in FAA-H-8083-21 (pg. 10-3), which calls for the maneuver to be performed slowly and smoothly with the primary emphasis on coordination.

 

COMMERCIAL PILOT 

Practical Test Standards

FAA-S-8081-16A, pg. 1-16

 

A. TASK: RAPID DECELERATION  

REFERENCE (S): FAA-H-8083-21; Helicopter Flight Manual.  

Objective. To determine that the applicant:   

1. Exhibits knowledge of the elements related to rapid deceleration.  

2. Maintains RPM within normal limits.  

3. Properly coordinates all controls throughout the execution of the maneuver.  

4. Maintains an altitude that will permit safe clearance between the tail boom and the surface.  

5. Decelerates and terminates in a stationary hover at the recommended hovering altitude.  

6. Maintains heading throughout the maneuver, ±5°.

http://www.faa.gov/training_testing/testing/airmen/test_standards/pilot/media/FAA-S-8081-16A.pdf

 

RAPID DECELERATION (QUICK STOP)

FAA-H-8083-21, pg. 10-3

In normal operations, use the rapid deceleration or quick stop maneuver to slow the helicopter rapidly and bring it to a stationary hover. The maneuver requires a high degree of coordination of all controls. It is practiced at an altitude that permits a safe clearance between the tail rotor and the surface throughout the maneuver, especially at the point where the pitch attitude is highest. The altitude at completion should be no higher than the maximum safe hovering altitude prescribed by the manufacturer. In selecting an altitude at which to begin the maneuver, you should take into account the over all length of the helicopter and the height/velocity diagram. Even though the maneuver is called a rapid deceleration or quick stop, it is performed slowly and smoothly with the primary emphasis on coordination.


http://www.faa.gov/library/manuals/aircraft/media/faa-h-8083-21.pdf


Regards,
Chris




ozloadieUser is Offline
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10/09/2010 2:52 AM  
I think there's an important add on here, particularly if you are considering a quick stop in confined spaces, planned or unplanned - it's the inclusive ability to be able to assess the wash off of momentum, as well as airspeed, to refine the technique as you go, or abort at a predetermined point. As Rocky pointed out, not all situations are going to be blueprint and what was ideal may fall over in the latter stages. There could also be "multiple" interupters unassociated with each other to create a flow of "re-decisions" for want of a better term, and you'd want that first decision point still in front to be ideal for an escape. Quick stops at altitude are an interesting exercise for preciion, because most of your references (apart from the panel) are below you. Practice makes perfect (again!) Steve.

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