WAAS enabled GPS for 24mth altimeter check

[Philster2001]

Hi Guys,

 

Apologies if this question has been asked before, but section 12.4, 2.1 of the RA-AUS technical manual Issue 4.1 March 2021 states the following:

 

“2.1 Altimeters must be checked every 2 years against a currently certified altimeter (a LAMEs test equipment) or other appropriate test equipment (e.g. a water manometer and scale, or a wide area augmentation system (WAAS) compatible GPS) and must not deviate by more than +/- 100 feet, up to the maximum normally expected operating altitude of the aircraft.”

 

My question is this: is it possible to use a WAAS compatible GPS for this purpose in Australia? A Google search seems to indicate that the WAAS system is USA based only.  Apparently there is a new system in Australia called the “National Positioning Infrastructure Capability (NPIC) but I can’t see any information as to whether WAAS enabled GPS’s can utilise this infrastructure. 
 

Thanks in anticipation. Phil

[KRviator]

Can't imagine it's useful to use GPS, as that's altitude above the theoretically perfect GPS ellipsoid, not AMSL. You're better off using a water manometer. Cheap, easy and can do it in the hangar for the cost of tubing and a few minutes on Google to print a suitable height to altitude chart.

[mkennard]

Also, the guy I used detected leaks and does the ASI as well.

[facthunter]

Vertical separation is by BARO even though GPS may be closer to actual on occasions, everyone must use the same reference.  Nev

[RFguy]

You cant use GPS to cal the barometric altimeter.....

unless you have calibrated and reliable barometer. But if you have one of those, you dont need the GPS. 

 

The GPS might be used for flying in a triangle to check the ASI.

 

 

[skippydiesel]

"The GPS might be used for flying in a triangle to check the ASI."

 

I always thought you had to do a triangle tp calibrate an ASI, but recently discovered you can just fly back & forth on a straight track & time yourself between set points.

[Thruster88]

CAO 100.5 items can only be performed by a LAME with the appropriate qualifications using equipment with current calibration. I don't think RAAus has a lesser standard.  

[RFguy]

Thruster88 is correct.

Certainly  (RAAUS) you can do all the tests yourself, rectify  unservicable items, then get the CAO 100.5 guy (I dont know any CAO100.5 women)  to come and measure it and sign it off.

This will minimize any hourly rate cost.

 

Edited November 23, 2023 by RFguy

[RFguy]

I'm going to ping RAAUS about the GPS bit in the tech manual