Did You Receive Good Training Part 2

[Mikemv]

Breaking away from Part 1 to keep thoughts flowing for everyone.

 

Original Info:

I list four situations and then ask a few questions to see what pilots have been taught or not!

 

We can use an R22 or S300 for thinking this through but the actual aircraft does not matter as much as the pilots thinking and response to a situation.

 

What have you been taught to do if the engine quits and:

1. you are at 40kts and 100' in level flight?

2. you are on climb out at 40kts and 100'?

3. you are descending to land and at 40kts and 100'?

4. you are in autorotation at 40kts and 100'?

 

Which of items 1 thru 4 are in a HV shaded area?

 

You can see the airspeed and altitude numbers are the same in all four cases.

 

Now for two questions:

 

1. Has anyone been taught to lower the nose to gain airspeed, do a no flare touchdown and slide?

2. Hold the attitude, flare appropriately, level and cushion?

 

If possible, please only answer the questions without explainations in this thread. Discussions can take place in another thread.

 

I am truly trying to research what pilots are taught and how they feel they would react?

 

OK, the new comments and hints!!!!!

 

Reading the 4 Scenarios, note that that ENGINE has QUIT! This is not a selective training autorotation! Some of you answered that in #4 you would recover?

 

What three aerodynamic transitions take place when going from powered flight to autorotative flight?

 

 

"Avoid pitching the nose forward on entry, especially if you are slow to lower collective, as the rotor speed could decay below limits." by Andy Roe

 

The "correct rotor speed in steady autorotation is specified in the flight manual and is set by increasing or decreasing the length of the pitch change links. Pitching the nose up in the descent will speed up the rotor and pitching forward will slow it down, until attitude is stabilized". A Quote from Andy Roe of Vertical Magazine in discussion of autos!

 

Now think about the time in seconds you have in an auto from 500'?

 

A few of these are for entry and a few more (3 or 4) during the flare and touchdown!

 

OK, now how many seconds do you have from 100'?

 

For those of you that said you would pitch for increase in airspeed, how much time do you have to do this before you must initiate a flare? (3 seconds maybe)

 

Will you reach 65kts as you stated?

 

What are the aerodynamics of the rotor system during entry, pitch over and flare all in about 7 seconds? Any aerodynamic stability here?

 

Pitching over will only decrease rotor rpm and increase sink rate! You want to do this at this point in time right?

 

What 3 things do we accomplish in a flare?

 

More hints: What parameters are used to establish the lower portion of the HV Diagram?

(say Take Off)

 

Only Scenario 2 is in the HV shaded area!!!!!!

 

The most successful autos will be completed with minimum rate of descent and ground speed and with maximum rotor rpm available.

 

OK, read thru the 4 scenarios again, think about the hints I have given you.

 

What are your answers now?

 

My point is that so many pilots have not been given instruction about so many things if it does not lead to discussion or testing by the PTS. This instruction could be done in a good ground school session if a CFI understood all of this.

 

It is all made clear in my "C&E Seminars". Safety through Education!

 

Be Safe,

 

Mike

Edited December 1, 2010 by Mikemv

[Mikemv]

Here is a link to Andys' article in Vertical Mag.

 

http://www.verticalmag.com/control/news/templates/?a=15368&z=21

 

Mike

[apiaguy]

I disagree that only #2 is in the hv curve.

All are in the curve, BUT the curve is based on "take-off" parameters would be a better way of discussing this.

If you changed the numbers to 15kts airspeed and 100ft would you still contend only #2 is in the HV curve?

Do you think it is possible to do a vertical 0 airspeed autorotation and land successfully without regaining forward airspeed?

1 and 2 are obviously the closest to what the published curve represents and your success would closely resemble the success associated with being on the outer edge of the curve.

3 and 4 would provide you a little leeway as your already in low power or unpowered flight and the precious time at 100 ft. and 40kts is not a good representation of success in the curve operations as you are close to the border already and not pushing forward would be an ok trade-off at that height.

 

If you change those numbers to 15kts and 100 ft... you MUST push forward or you are a pancake.

 

Stan's experience could be better summarized by saying he should have flared more and applied collective in the flare until he needed to level the ship...his decision to push forward to attempt to gain some more airspeed was maybe not the best choice but was not incorrect either in this situation.

Edited December 1, 2010 by apiaguy

[Mikemv]

apiaguy, you can disagree but Certification and formulation of HV are not up to you. You can change numbers but when the HV curve is formulated around Take off in the lower section and cruise in the upper section, pitch is in the blades and a climb is taking place in the lower section. If you are not climbing, you are not in the lower section by definiton and formulation. I did not make this up. Read FAR Part 27.

 

Switching numbers around does not change that #1 you are level, #3 you are descending and #4 you are in autorotation so yes, only #2 is in HV diagram by certification, formulation and aerodynamics!!! You made my point in showing the lack of understanding of how aerodynamics is part of HV not just numbers of A/S and Alt.

 

There is no HV shaded area that is formulated around a helo in level flight in the lower portion, a descent or autorotation. Descents and autos are not part of the certification or data to make HV. The certification/test pilots climb in the lower section and never plot any numbers in a descent or auto.

 

Pushing forward from 100' only decreases rotor rpm and increases rate of descent! Why would you think you could gain any useable airspeed to use in a flare to transfer energy to the rotor in a few seconds. Pancake is not reality by holding attitude, conserving rotor rpm, flare as you can/desire, level, use inertia to cushion in a level attitude.

 

From 100' and zero airspeed you ask could I do an auto without getting airspeed? I have done these in training environment, rolling off the throttle in various airframes. The key here is to know what to do with the collective, rotor loading and timing! How much airspeed do you think you can get from 100', flare and use to make a difference?

 

 

Again this is not about Stans' event. This was a thread to see how many pilots do not understand the HV diagram and the aerodynamic transitions that take place.

 

You did not answer the question about what aerodynamic transitions take place?

 

Mike

[apiaguy]

your right... I'm way out there... probabally because I haven't attended one of your motivational seminars where you spell it out.

[Pohi]

 

There is no HV shaded area that is formulated around a helo in level flight in the lower portion, a descent or autorotation. Descents and autos are not part of the certification or data to make HV. The certification/test pilots climb in the lower section and never plot any numbers in a descent or auto.

Mike

 

I'll just leave this here...

 

§ 27.87 Height-speed envelope.

top

 

(a) If there is any combination of height and forward speed (including hover) under which a safe landing cannot be made under the applicable power failure condition in paragraph ( of this section, a limiting height-speed envelope must be established (including all pertinent information) for that condition, throughout the ranges of—

 

(1) Altitude, from standard sea level conditions to the maximum altitude capability of the rotorcraft, or 7000 feet density altitude, whichever is less; and

 

(2) Weight, from the maximum weight at sea level to the weight selected by the applicant for each altitude covered by paragraph (a)(1) of this section. For helicopters, the weight at altitudes above sea level may not be less than the maximum weight or the highest weight allowing hovering out-of-ground effect, whichever is lower.

 

( The applicable power failure conditions are—

 

(1) For single-engine helicopters, full autorotation;

[280fxColorado]

Ok Mike, I'll play. Be gentle...

 

"What have you been taught to do if the engine quits and...:" You are spot on about deficiencies in initial training. You ask what we've been taught to do in these situations. By and large, we are not taught how to handle these specific critical situations--certainly not out of most POHs or the RFM. This is what I've picked up over the last 5 years...

 

"1. you are at 40kts and 100' in level flight"-- Drop collective asap, gentle aft cyclic to maintain level attitude = preserve rotor RPM, add right pedal. Stabilize in glide, begin flare at 20-30ft' agl. Slower airspeed than normal auto will require a more aggressive flare to reduce rate of descent. Slower airspeed will also make the flare less effective--you will sink through it--requiring a prompt leveling of the ship (to avoid TR strike) and anticipate a run on. DO NOT expect to bring helicopter to a standstill at a 3-5 foot hover. Flare duration and effectiveness will be less than ideal/practiced autos. Everything will happen very quickly so it's hard to break down the control inputs into steps--it will be a smooth, rapid, coordinated, progressive maneuver. Perhaps a gradual upwards collective movement through the flare and leveling, into the cushioned run-on? Use all the collective you've got! Pump it to the roof!

 

"2. you are on climb out at 40kts and 100'?"-- Roughly the same as #1 except this situation is more critical. Higher pitch angles during climbout means rRPM will decay much more quickly. Dump collective to floor ASAP and aft cyclic as necessary to get RPM back in the green arc. Descend in a level attitude and flare through 20ft, leveling out just prior to touch down. Smooth upward collective as you flare and maxing out up-collective just prior to touchdown. Expect a hard landing and a run on and hope you don't bend any metal (...nice work Stan...). This is a bad situation and I'm not sure that I've nailed it. Anxious to hear YOUR method.

 

"3. you are descending to land and at 40kts and 100'?"--Similar to above but pitch angles will be low on descent and RPM will not decay as quickly. Again, dump collective to floor, maintain level aircraft attitude, begin flaring at 20-30 feet coupled with a collective bump-up, well timed smooth forward cyclic to level ship before 3-5' agl, and collective to the roof to cushion (as before, throughout the flare and leveling). Like before, I anticipate a run on of ~15kts (and hope for forgiving terrain).

 

"4. you are in autorotation at 40kts and 100'?--" This is the most manageable and probably the only situation in which I would consider nosing over for speed. In practicing advanced autos (0-speed entry or decelerate-to-increase-RoD/shorten glide distance) I've found that diving for airspeed costs 100ft altitude per 10mph gained (ie. it takes 100ft to dive from 40kts to 50kts and regain a level flight attitude). We're only at 100ft here so not much wiggle room! But, you are already autorotating and IFF RPM is stabilized top of green, might a smooth momentary nose over into an aggressive flare be beneficial? The increased speed will put us closer to the bottom of the airspeed/RoD bell curve, decreasing RoD. But the airflow will become more horizontal over the disc, reducing our blades AoA. This decreases the lift produced by the driving region, but would it also shorten the size of the stalled region increasing total rotor thrust? The increased airspeed should make the flare more effective... but at what cost? Ahh!! so many variables, hard to balance them out. What IS the official recommended procedure, Mr. Franz?

 

What three aerodynamic transitions take place when going from powered flight to autorotative flight?

 

#1. Entry-- induced flow from above the disc is replaced with airflow from below and forward (a combination of forward airspeed and rate of descent). the total aerodynamic force vector tilts forward, the nose tends to dip, and rpm decreases.

#2. Steady state descent-- The changed airflow across the rotor disc divides the blades into three regions--stalled, driven, and driving. total aerodynamic force vector continues to move forward and maxes out when RoD, RPM, and airspeed stabilize.

#3. Flare -- AoA increases, RPM increases, total aerodynamic force vector increases and inclines rearward, rate of descent and forward airspeed decrease.

 

 

"Now think about the time in seconds you have in an auto from 500'?"

25-30 seconds

 

"OK, now how many seconds do you have from 100'?"

6-8 seconds?

 

"Will you reach 65kts as you stated?"

hell no.

 

This is a great topic for discussion and I am anxious to hear your recommendations.

Edited December 3, 2010 by 280fxColorado

[Spike]

 

"Now think about the time in seconds you have in an auto from 500'?"

25-30 seconds

 

"OK, now how many seconds do you have from 100'?"

6-8 seconds?

 

 

One of my colleagues had the engine fail at 500 feet in an AS350. He was on the ground in 17 seconds. I had a failure at 500 feet in a S300. I hit the ground in about 8 seconds. Theory teaches what may be possible…….

[Mikemv]

280FX, thank you for a sincere reply. This is what I hoped for in Part #1, so I could get an understanding of the knowledge base of posters. Many previous posts where just quick statements without actually answering the questions. Maybe I hoped for too much.

 

I intend to make a Thread #3 and give out info about the questions even though some of it is inter mixed in #1 & #2. All of you are not alone in this, we need to fix these areas of lack of understanding, lack of training and misconceptions to reduce accidents and produce better pilots & CFIs. No telling when you could find yourself at 40/100 and have to face this. If we at least discuss it here or in C&E Seminar, or with your educated CFI, you will do the best you can based on what you know. I am working on it and ask everyones help in doing so.

 

Document attached.

 

Thanks,

 

Mike

280FX response.doc

[Mikemv]

One of my colleagues had the engine fail at 500 feet in an AS350. He was on the ground in 17 seconds. I had a failure at 500 feet in a S300. I hit the ground in about 8 seconds. Theory teaches what may be possible…….

 

Yo Spike, how could this be? 500'/8= 62.5'/sec. or 3,750'/min. Rate of Descent

 

We we consider that the flare takes about 3 second time to cushion, then ROD goes to 6,000'/min!

 

Great job getting the ROD stopped.

 

How did things turn out for pilot, pax and airframe?

 

Mike

[Pogue]

280FX, thank you for a sincere reply. This is what I hoped for in Part #1, so I could get an understanding of the knowledge base of posters. Many previous posts where just quick statements without actually answering the questions. Maybe I hoped for too much.

From your initial Part 1 post:

"If possible, please only answer the questions without explainations in this thread. Discussions can take place in another thread."

 

That may have something to do with the short responses.

[Mikemv]

From your initial Part 1 post:

"If possible, please only answer the questions without explainations in this thread. Discussions can take place in another thread."

 

That may have something to do with the short responses.

 

Pogue, what should I say to get posters to answer the questions, other than please only answer the questions? Most did not answer the questions!

 

Mike

[Pogue]

PM sent to avoid wandering off topic.

[Spike]

Yo Spike, how could this be? 500'/8= 62.5'/sec. or 3,750'/min. Rate of Descent

 

We we consider that the flare takes about 3 second time to cushion, then ROD goes to 6,000'/min!

 

Great job getting the ROD stopped.

 

How did things turn out for pilot, pax and airframe?

 

Mike

 

About 8 seconds.

 

I apologize for not following your rules when posting my short reply. I just thought some reality based information is better than theory.

 

To answer your question; I cant tell you what the rate of descent was. I was too concerned about not dying. My point is; the real deal is vastly different then training. Therefore, I can only assume this is the reason why the math doesnt add up. As a teaching tool, Id say with all of your scenarios, you do what you have to do in order to survive.

 

The ship and pax turned out fine.

 

Again, sorry for the slight highjack....

Edited December 3, 2010 by Spike

[Mikemv]

Spike, obviously you handled the emergency situation extremely well. You are correct that math is just math but your skills in flying are what saved your butt. Being a pilot and flying the helo all the way to the ground, never giving up is the way to go! Bravo.

 

Having the knowledge and skill sets to handle emergencies are what pilots need and what the Industry has me trying to fix.

 

Keep flying save, handle what comes up, best wishes,

 

Mike