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10 Answers

Procedure turn

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Instrument Rating

Hi! Please look at this approach plate: http://www.theatlantic.com/technology/archive/2010/07/reference-document-on-the-pakistan-crash/60545/ My questions: 1. When do you start descending to 3900 ft? From D10 point or when established inbound? 2. Why the line after the D10 is curving. In all the approaches I saw before, the outbound line meet the inbound line at an angle? 3. Some Jeppesen approach plates had a gray area in the profile view with altitude. I searched to find an answer and i found in jeppesen intriduction that those are are called Segment Min Alt butwhich i never heard of before. Any idea?Note: I have searched the net about the curvy turn and I found that it is called a descending turn but no further explanation given.

10 Answers

  1. John D Collins on Nov 01, 2013

    I read the chart to mean that once past the RN VOR (9500) and established on the RN 160 radial, you may descend to 6500. At 9 DME RN and 160 degree radia you may start the descent to 3900. Also at this point, you start the turn to 060, and continue the descent to 3900. At the RN 10 DME and the RN 130 degree radial you begin the turn to 340 and intercept the localizer at approximately 8 DME RN. Established on the localizer and past 8 DME RN, you can start the descent to 2940 to intercept the GS (more likely only used if flying a localizer only approach) or you can remain at 3900 and intercept the GS at that altitude. Also at that point, you need to retune the DME to be based on IRN Localizer DME.

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  2. Lion on Nov 01, 2013

    Thanks John,

    What you said make sense because If we maintain 6500′ until established on final, we will be too high.


    Why we are taught during our IR training NEVER to descent to minimum GS intercept altitude until established inbound?

    For John and other follow pilots, is there a reference that states clearly that we may descend to the minimum GS intercept altitude at the end of the o/b leg of the PT as we are turning to the final course w/o having to wait until established?

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  3. John D Collins on Nov 01, 2013

    You must read the charts as they are charted. Some approaches are charted to permit descent in the PT, whereas others are not. This is specified in the profile view. If the descent is charted after the completion of the PT, then you must be established on the charted course prior to descending. There currently isn’t a good definition for what established means, but the PTS does specify acceptable criteria which is 3/4 full scale needle deflection. The FAA has written proposed updates to the AIM that will indicate that established in this situation is when the CDI is half full scale, but I don’t think it is yet published. The FAA indicates that full scale is established for RNP operations, but IMHO this is an engineers point of view and not a practical one for a pilot.

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  4. Muhammad Arif on Nov 01, 2013

    1. You start decent for 3900 from D9.0 till D8.0. Mean at D9.0 your height was 6500 ft and at D8.0 your height must be 3900 ft to establish on localizer.

    2. After D10.0 the line is curving, Might be due to any obstacle nearby.

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  5. Muhammad Arif on Nov 01, 2013

    and yup Lio couldn’t get your 3rd Question, can you mark that grey area on OPRN chart. which you talking about in profile view ?

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  7. ccwebb on Nov 04, 2013


    John said it best. I actively preach/teach this to my students as well. You fly the approach EXACTLY as depicted. Do not make up your own.

    If the approach plate has published altitude to intercept the glide slop (3900 feet) then fly 3900 feet. If you are unable to hold that altitude, then a technique used is round up to the next nearest hundred… 4000. If you wish to fly the localizer, then you can go down to 2940 feet, or 3000 if unable to hold that altitude. (I use this technique very sparingly. The whole purpose of the altitudes are to get out of the clouds. If 60 feet gets me out…yea!)

    The procedure turn’s initial segment INCLUDES the actual 45-degree turn. The intermediate segment begins once inbound. You stay at one altitude outbound, then turn to inbound, then descend. (John, you are correct about intercepting.)

    On this approach plate, it shows the course reversal turn with a ‘curve’, not a procedure turn. You can begin descending on the curve because it depicts it that way.


    Refrence page 1-20

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  8. Mark Kolber on Nov 05, 2013

    ccwebb said “The whole purpose of the altitudes are to get out of the clouds.”

    Actually, the whole purpose of the altitudes is to a avoid hitting something. With the DME stepdown it allows you to go lower without hitting something after a certain point.

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  9. ccwebb on Nov 05, 2013

    Well, guess were both wrong on that. If we use the word “and” then it would be proper.

    The purpose of altitudes listed on approach plates is to get out of the clouds AND have obstacle avoidance.

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  10. Mark Kolber on Nov 06, 2013

    True, true 🙂

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