Approach Techniques

[Goldy]

Robinson also recommends the 3-2-1 rule (maybe it's even in one of the Safety Notices...?), but p160 of Principles of Helicopter Flight shows a graph of ROD vs KIAS, with Angle of Descent overlaid. According to that diagram, steep approaches at Angles of Descent >50 degrees, a rate of descent >500 fpm, and airspeed <10 KIAS are when you have to worry.

 

Kodoz- the SN lists it as anytime you are greater then 300 fpm descent and less than 30 knots forward speed....you're in trouble. They also state to always decrease your ROD below 300 fpm before letting your airspeed get under 30 KIAS.

 

SN 22

 

http://www.robinsonheli.com/srvclib/rchsn22.pdf

 

Goldy

[Pohi]

Butters,

 

You are probably flying with inexperienced instructors. Ask them if a helicopter at a light weight or heavy weight will enter VRS at a lower ROD. Most will say a heavier weight.

 

I think Butters is probably flying with instructors who follow what the R22 POH says under normal procedures for approaches. The instructors are probably trying to teach students to follow the procedures and cautions that a helicopter manufacture suggests.

 

IMO, students should fly traffic patterns to the runway/pad then hover taxi to the parking spot at the end of a lesson. Sure helicopters can just do the Hollywood approach across the middle of the airport and runways and drop onto the parking spot, but learning and practicing the recommended procedures can't hurt.

[kodoz]

SN 22

 

http://www.robinsonheli.com/srvclib/rchsn22.pdf

 

Goldy

 

You are correct...it's the Rotorcraft Flying Manual that likes approaches 20% power, and below ETL ("

[RockyMountainPilot]

Yes but you can't see that on an instrument installed in a R-22. Until the student can get their approach under control (to a spot out in the desert they have never been to before) it keeps them out of trouble and helps them make a go around decision earlier if needed. Steep approaches come later and use a normal approach until you get to the obstruction that requires it to be steep.

 

Jerry

 

I don't want my students looking at the the instruments that much when flying VFR. I want them to look outside. And you don't need an instrument to determine approach angles. Just pick spots on the windscreen.

[Inferno]

Allright, I've been watching this thread for a while and feel the need to contribute.

 

There are many ways to do approaches without putting the helicopter at risk. How this came to a discussion of VRS, I'm not sure, as we know all about that and how to avoid it.

 

If I'm in a hurry and not in a training setting, my favorite approach into the airport I fly out of is a fast (50-60 kts) approach transitioned into an air taxi to the parking area. This saves quite a bit of time and in the summer where we fly in 100 degree F weather it saves a ton of cooldown time. (its basically what goldy described, except I add the air taxi onto it usually)

 

If its a training environment, go by the PTS (since this is what the student will be tested on). Shallow, normal and steep to a desired spot (usually on the runway at a taxiway... Then you hover taxi to the parking area.

 

One thing that i constantly see that bugs me is the fly by numbers technique. Flying should be visual. Obviously, you should cross reference your instruments to make sure when you pass through 30 KTS you have

 

That being said, when preforming the normal 3 types of approaches, the rule of thumb on altitude airspeed you should be at when turning final is very handy.

 

Oh well, thats just this poor little CFI's opinion....

[Goldy]

Obviously, you should cross reference your instruments to make sure when you pass through 30 KTS you have >300 Ft/min rate....

 

Agreed, but since we have students reading these, I have to correct you on one little typo. It's <300 FPM not, >300FPM..

 

I hate typos. I make them myself all the time!

 

Goldy

[Inferno]

Hah, thanks. Proofreading was never one of my strong points... And I type way too fast.

Agreed, but since we have students reading these, I have to correct you on one little typo. It's 300FPM..

 

I hate typos. I make them myself all the time!

 

Goldy

[RockyMountainPilot]

One thing that i constantly see that bugs me is the fly by numbers technique. Flying should be visual. Obviously, you should cross reference your instruments to make sure when you pass through 30 KTS you have <300 Ft/min rate.... The whole at x ft you should be a x speed and x decent rate thing is going at it completely wrong.

 

Why cross reference at all? Why not just fly an approach angle of 30 degrees or less. Then you don't need to worry about VRS at all as long you you don't make a downwind approach.

 

30 knots and 300 FPM less than a 6 degree slope angle. At 30 knots, you can have up to a 1500 FPM descent rate and still be less than 30 degrees. Easier to keep the eyes out side and look at approach angles, than you look at your instruments.

[Helo-Pilot]

Butters, keep flying, and always, always try to keep learning.

 

As your skill level increases so will your ability to 'modify' an approach to suit the needs of your flight.

 

As a low time pilot, an approach like you described, 60@60 50@50, etc., would have made me very nervous, and looked like hell. Now that I have a few more hours, I could, and have flown that approach because it was what I need to do in my situation.

 

Study your books, understand how and why things like SWP happen, and then train with your CFI to recognize the onset, and how to recover. Again, as your experience skill level increases, you will be more comfortable with different approaches and all of the variables that come with each one.

[IFLY]

I guess I should add that the students are looking outside BUT do glance at the instruments to verify that what they are doing is not going to get them in trouble. Its just a cross check.

 

Jerry