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4 Answers

ALTIMETER SETTING IN UNCONTROLLED AIRSPACE

Asked by: 7382 views Airspace

HELLO.

EXAMPLE) 10 MINUTES AGO, YOU WERE BEING CONTATED BY CONTROLLER FOR MONITORING. THEY GAVE YOU AN ALTIMETER INFORMATION WHENEVER IT SHOULD BE CHANGED. 

NOW YOU'RE FLYING IN UNCONTROLLED AIRSPACE AND WANT TO LAND IN AN NEAR UNCONTROLLED AIRPORT.

THERE IS NO AWOS. NOBODY IS FLYING AROUND THERE.

WHO IS GONNA GIVE YOU AN ADVISE FOR ALTIMETER?

 

4 Answers



  1. Cory Johnson on Apr 03, 2013

    If you’re only 10 min from the last altimeter reading, it’s probably close enough for your needs.

    If possible, locate a nearby airport that has AWOS/ASOS and monitor it. For example, my local airport (14A) does not have automated weather, so we tune in AWOS at the closest facility (KSVH) which is about 10 miles away.

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  2. Best Answer


    John D. Collins on Apr 04, 2013

    The requirement to obtain the altimeter system is rather loose, particularly if you are VFR. It applies to both controlled and uncontrolled airspace. The closer to your airport and altitude of the remote reporting station, the better. But if you are just landing at a VFR airport, any altimeter setting within 100 NM complies with the regulations.

    If you are IFR, then you will want the local altimeter setting. If one isn’t available, the approach chart will tell you where to obtain it. Any time a remote altimeter setting is used, it will affect the minimums available for the approach. If the airport normally has an altimeter setting available, but is out of service, the chart will inform the pilot where to obtain the remote altimeter setting and how to adjust the minimums for the approach.

    Sec. 91.121

    Altimeter settings.

    (a) Each person operating an aircraft shall maintain the cruising altitude or flight level of that aircraft, as the case may be, by reference to an altimeter that is set, when operating–
    (1) Below 18,000 feet MSL, to–
    (i) The current reported altimeter setting of a station along the route and within 100 nautical miles of the aircraft;
    (ii) If there is no station within the area prescribed in paragraph (a)(1)(i) of this section, the current reported altimeter setting of an appropriate available station; or
    (iii) In the case of an aircraft not equipped with a radio, the elevation of the departure airport or an appropriate altimeter setting available before departure;

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  3. Bill Trussell on Apr 04, 2013

    When considering your question it is important to note why we have altimeters that are settable. The setting is intended to compensate for non standard pressure in any one area. The correction is applied as if everyone was at sea level. The idea being that if there are two or more aircraft in one area, everyone should be measuring altitude using the same starting point, thus contributing to separation.

    In your example there is not enough distance from the last advisory from ATC to warrant any significant adjustment to the altimeter and thus everyone in the area should be using the same measurement starting point.

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  4. Namugoni on Apr 05, 2013

    thank you!!

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