1. This site uses cookies. By continuing to use this site, you are agreeing to our use of cookies. Learn More.

Altimeter Setting vs Field Elevation

Discussion in 'CFI Corner' started by Vflyer, Apr 13, 2017.

  1. Vflyer

    Vflyer Well-Known Member

    Joined:
    Jul 12, 2013
    Messages:
    25
    Likes Received:
    9
    The last couple of flights I've had I noticed the altimeter did not match the field elevation when inputting the current baro pressure from ATIS. In fact it was off by 150-200ft. I'm embarrassed to admit I can't figure out why. I was trying to equate it to temperature, but it would seem the pressure at a given level, is the pressure regardlesss of temp.

    The field is basically at sea level (10ft) yet the altimeter typically indicates 200ft below this. It makes me wonder if I should be accounting for this "error" or assume the altimeter setting is correct and fly at assigned altitudes regardless.

    I did some googling to no avail so hopefully this question isn't too dumb!
     
  2. gotWXdagain

    gotWXdagain Highly Visible Member

    Joined:
    Jan 17, 2009
    Messages:
    2,985
    Likes Received:
    2,385
    Not a legal IFR altimeter, you probably want to get it looked at.
     
  3. Roger Roger

    Roger Roger Navajo Whisperer

    Joined:
    Sep 4, 2009
    Messages:
    7,141
    Likes Received:
    8,438
    Yeeeep sounds like you need an altimeter.
     
    z987k likes this.
  4. z987k

    z987k TeamANC

    Joined:
    Feb 3, 2010
    Messages:
    11,033
    Likes Received:
    6,657
    It's likely the altimeter.
     
  5. Cessnaflyer

    Cessnaflyer Wooooooooooooooooooooooooooooooo

    Joined:
    Dec 9, 2006
    Messages:
    8,202
    Likes Received:
    2,448
    Temperatures do have affect reading but I doubt it was cold enough at sea level to be reading 200 feet lower unless you were in the polar regions.
     
  6. Vflyer

    Vflyer Well-Known Member

    Joined:
    Jul 12, 2013
    Messages:
    25
    Likes Received:
    9
    Thanks that's good to know. The plane is a rental so best I can do is squawk it for now. I don't think it gets used much for ifr so there probably won't be much motivation to fix it.
     
  7. drunkenbeagle

    drunkenbeagle Gang Member

    Joined:
    Mar 18, 2009
    Messages:
    7,365
    Likes Received:
    2,884
    I would consider 200' to be a safety of flight issue. If it is a rental, vote with your feet. Don't fly it until it is fixed or replaced (more likely). They aren't that expensive...
     
  8. Roger Roger

    Roger Roger Navajo Whisperer

    Joined:
    Sep 4, 2009
    Messages:
    7,141
    Likes Received:
    8,438
    This is why I started doing altimeter certs even on our VFR only planes.
     
    Last edited: Apr 15, 2017
    BigZ likes this.
  9. Roger Roger

    Roger Roger Navajo Whisperer

    Joined:
    Sep 4, 2009
    Messages:
    7,141
    Likes Received:
    8,438
    About 12 airplane bucks for the ones we use. Might could get it repaired but typically the shop says that by the time they're that far out it's cheaper to buy a new one than to replace, depending on the age and type of altimeter. Of course a real operation should have a current cert altimeter on hand that they could swap in and not have an AOG but...
     
    Last edited: Apr 15, 2017
  10. drunkenbeagle

    drunkenbeagle Gang Member

    Joined:
    Mar 18, 2009
    Messages:
    7,365
    Likes Received:
    2,884
    By aviation standards, pretty damn cheap. I though airplane bucks were the same as boat bucks though - those are usually "large." Like, if it isn't in thousands, it isn't real money yet...
     
  11. Roger Roger

    Roger Roger Navajo Whisperer

    Joined:
    Sep 4, 2009
    Messages:
    7,141
    Likes Received:
    8,438
    hahaha yes very similar...so maybe 1.2 airplane bucks would be more accurate
     
  12. BaronPete

    BaronPete Jaw Harp Troubadour

    Joined:
    May 14, 2008
    Messages:
    785
    Likes Received:
    53
    So an altimeter replacement is about 1200$ ?

    I realize everything is expensive, but I wouldn't have guessed that. I figured 400-500 tops.

    But then again, I'm dumb.
     
  13. Roger Roger

    Roger Roger Navajo Whisperer

    Joined:
    Sep 4, 2009
    Messages:
    7,141
    Likes Received:
    8,438
    Yup, for an analog TSO replacement.
     

Share This Page