Correct way to fly the Procedure Turn?

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Hop Harrigan
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Correct way to fly the Procedure Turn?

Unread post by Hop Harrigan » Sat May 28, 2016 6:02 pm

Hi,
My IF instructor taught me to fly the Procedure Turn in what appears to be a bit of a non-standard way. The DFE raised his eyebrows when I did the test but passed me anyway. So my question is what is the correct way to fly this manoeuvre?
The standard way to fly is (with acknowledgement to D L Howarth) is to:
Overfly the beacon on the outbound heading for a calculated time and then execute a 45 deg. offset for 1 minute, followed by a turn back to the inbound heading. See attachment.
I was taught to:
Overfly the beacon and immediately execute a 45 deg. offset for 1 minute, turn to the outbound heading for a calculated time followed by a turn back to the inbound heading.
My instructor was of the opinion that this was the 'modern' thinking and that it reduced the workload in the overfly position.
I am not convinced...any opinions??
Hop
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Re: Correct way to fly the Procedure Turn?

Unread post by DipStick » Sat May 28, 2016 6:45 pm

Hi Hop,

I disagree with your instructors "thinking".

See below excerpt from ICAO Doc 8168:
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Re: Correct way to fly the Procedure Turn?

Unread post by Hop Harrigan » Sat May 28, 2016 8:06 pm

Hi Aidan,
Yes, the top line in that diagram is the standard method. You ever tried the other method I described?
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Re: Correct way to fly the Procedure Turn?

Unread post by DipStick » Sat May 28, 2016 8:37 pm

Hi Hop,

Nope, never heard of that method until now.

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Re: Correct way to fly the Procedure Turn?

Unread post by Romeo E.T. » Sat May 28, 2016 8:50 pm

Hop Harrigan wrote:Hi Aidan,
Yes, the top line in that diagram is the standard method. You ever tried the other method I described?
Hop
hello Hop

your described method, although contrary to the theoretical writings, has only one advantage, in that instead of attempting to attain and maintain the outbound QDR/Radial before commencing the turn thru 45deg, you immediatelly do the 45 deg turn, then parrallel until the required DME/Time before commencing a normal inbound turn to intercept the inbound QDm/Radial

too many new IF students spend inordinate amount of time and effort to attain the accurate outbound QDR/Radial, and then overshoot their desired point at which to commence the 45 deg turn, and this invariably leads them to exceed the lateral outbound DME/Timing, due to overload and loss of Situational Awareness.

That is the only reason why some "modern" instructors believe that to get the 45 deg turn out of the way ASAP, then the remainder of the concentration can be on the lateral limits of DME/Timing before commencing the inbound turn
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Re: Correct way to fly the Procedure Turn?

Unread post by CLFO » Sun May 29, 2016 8:40 am

In a stiff crosswind you might end up either too far away from or too close to the inbound radial.
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Re: Correct way to fly the Procedure Turn?

Unread post by Hop Harrigan » Sun May 29, 2016 9:10 am

Hi Romeo,
That makes sense...so why is this method not more widely used?
Considering that this is different from the legal published method, do you guys think this is actually legal,
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Re: Correct way to fly the Procedure Turn?

Unread post by Wildcat_003 » Sun May 29, 2016 9:47 pm

Hi guys. Let's take FABL runway 20 VOR as an example. On passing the facility(BLV) you must intercept the outbound radial for 1-3 minutes or you can even go to 6 DME and now comes the important part: timing starts as the turn to 45 degrees is started and it's for 1 minute. If you started the 45 degrees at 6 DME and after 1 minute you turn back onto the outbound heading you will, in no wind conditions get 8 DME as you turn through the outbound heading and you just continue your turn inbound to intercept the inbound radial. If you went outbound 1-3 minutes it's no problem. Timing is also 1 minute from initiating the turn and after 1 minute just turn onto the outbound heading and continue to 8 DME and then commence the inbound turn. The criteria is to get to the 8 DME position. With wind you just have to correct for it. Why intercept the outbound radial: all turns are rate one and if you don't fly the procedure correct how will you get to the 8 DME position?
Flying the procedure as above is the only way to fly the procedure turn correctly. Been doing this for many years ....and it works.
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Re: Correct way to fly the Procedure Turn?

Unread post by Hop Harrigan » Mon May 30, 2016 8:09 am

Hi Wildcat,
But why not make the 45 deg turn directly over BLV and then fly for 1 minute, turn onto the outbound heading and at the 8 DME point turn back to the inbound? I understand that this is not the 'normal' way of doing it but I'm trying to establish the 'best' method so that I can stay current on one method only.
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Re: Correct way to fly the Procedure Turn?

Unread post by Iceberg » Mon May 30, 2016 9:58 am

Hop Harrigan wrote:Hi Wildcat,
But why not make the 45 deg turn directly over BLV and then fly for 1 minute, turn onto the outbound heading and at the 8 DME point turn back to the inbound? I understand that this is not the 'normal' way of doing it but I'm trying to establish the 'best' method so that I can stay current on one method only.
Hop
I would also stick to the standard way of doing it.
When you pass over the beacon for the outbound portion, stick to the outbound radial using the VOR.
Then if there is a crosswind, add 5-10s in the 45 deg portion if you are into the wind, otherwise subtract say 5s if you have a tailwind.
If you can go out further - say 2 minutes - you have more time to correct the inbound course if the wind is strong.
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Re: Correct way to fly the Procedure Turn?

Unread post by Wildcat_003 » Mon May 30, 2016 12:36 pm

Hop, I have not seen your type of approach ie turning 45 degrees overhead the facility. The 1-3 minutes outbound is your last opportunity to assess the wind and will permit you to get to the 8DME fix more accurately. Look at all the procedure turns in the Jepp and you will see that they normally show the 45 degree turn 2 DME before the eventual outbound leg distance. I find this one the most accurate.
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Re: Correct way to fly the Procedure Turn?

Unread post by ACE MAN » Mon May 30, 2016 1:29 pm

Hop , stick with the standard procedure turn otherwise you are messing with procedure design. Nice to experiment with , but not the way it is designed.
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Re: Correct way to fly the Procedure Turn?

Unread post by Romeo E.T. » Mon May 30, 2016 1:39 pm

Hop

whilst it is good to have an "open mind" as this discussion demonstrates,
when you are going into an IF renewal scenario, and worst of all, you dont pre-brief the testing officer, of this method, that is when the confusion begins.

Your queried procedure was introduced to me in the B737 simulator by the training captain, and I can "see" the benfits as well as the draw backs, but when it comes to a testing/renewal scenario, it is always better to either (1) follow the basic theoretical procedure and/or (2) discuss this procedure in the briefing room prior to starting the flight test itself

Maybe throw this exact scenarion into Flight sim, and dial in a nice cross-wind, then fly the various options and view the track plot afterwards to make up your own mind.
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Re: Correct way to fly the Procedure Turn?

Unread post by Hop Harrigan » Mon May 30, 2016 5:02 pm

Gents,
Many thanks for the advice..the argument to stay on the outbound heading directly from the beacon in order to ascertain the required crosswind correction seems to be the strongest reason for staying with the standard method. The method of turning 45 deg at the beacon does however give one more time before the inbound turn to get ones A-into-G.
I run an SR22 sim on Xplane/FlyThisSim and will fly both methods to settle the issue in my mind.
Does anyone know...are the recommended methods the only legal ones or is anything legal as long as one stays within the racetrack and prescribed alts??
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Re: Correct way to fly the Procedure Turn?

Unread post by jalopysled » Fri Sep 30, 2016 8:07 pm

I think Hansie's accident gives a good idea as to why you want to be provided with tracking accuracy - after the missed approach they turned onto the outbound heading straight away, instead of following the missed approach (given, the turn outbound was also a steep turn - so that was probably the straw that broke the horses back), but they ended up in the wrong starting position for the outbound leg and that put them on the wrong side of the hold.
They had a GPS on-board with track information, and in fact the FO mentioned their track (strong southerly wind, approximately 10 degree drift towards the granite) when they had earlier established themselves in the hold... But these sorts of things will slip your mind if flying single pilot in IMC.
PANS-OPS may give you guidance as to the correct method to do it. My belief is that the procedure was designed using ground based nav-aids solely - therefor you need the track guidance on the outbound radial/QDR until you make the turn.
If you wish to make the turn immediately overhead the beacon, then level wings and fly outbound to the limiting DME, you have no track accuracy and could find yourself who knows where.
And saying that you will rely on GPS track guidance now blurs the lines between Gnd-based navaids and established GNSS procedures... Cherry picking.
If I was the DFE I would also frown upon that sort of advice to fly a very simple maneuver.
My advice - if you are rated, the aircraft is equipped with what it needs to fly a GNSS approach, then fly it rather... But if you are flying ground based navaid approaches - use the GPS as an aid - and fly the procedure the way it was designed - outbound on the radial to a certain distance, and then turn

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