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19 votes

What is a blind encoder?

A blind encoder is an altimeter that encodes pressure altitude and outputs it on a databus. They are "blind" in that they do not display data to the pilot. Most general aviation units use a parallel ...
Gerry's user avatar
  • 20k
8 votes
Accepted

Why do ADS-B outages occur without simultaneous RAIM outages?

RAIM (Receiver Autonomous Integrity Monitoring) is a function within an avaition GPS receiver. It uses redundant measurements for a consistency check to determine the intergrity of the position ...
DeltaLima's user avatar
  • 83.6k
8 votes

Why do some GPS receivers suppress RAIM integrity warnings after you pass the FAF?

As ymb1 commented, RAIM was introduced in TSO-C129 receivers. These were the first GPS receivers certified and they were only approved for supplemental navigation (You were required to also have an ...
Gerry's user avatar
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3 votes
Accepted

Why are SBAS-equipped planes exempt from the preflight prediction check?

The slide refers to ADS-B integrity, which requires a different integrity level than RNP. The ADS-B preflight check they refer to is a different than the check for RNP. The FAA requires an integrity ...
DeltaLima's user avatar
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3 votes

Must RAIM be checked in flight before every GPS approach or is a preflight check acceptable?

The FAA website predicts pre-flight whether RAIM will be available The RAIM algorithm will tell you during your flight if GPS is working correctly. The pre-flight FAA website check is not a ...
DeltaLima's user avatar
  • 83.6k
1 vote

Must RAIM be checked in flight before every GPS approach or is a preflight check acceptable?

Answer lies on AIM 5-1-16 "rnav and RNP operations" paragraph f: f. During the pre−flight planning phase RAIM prediction must be performed if TSO−C129() equipment is used to solely satisfy the ...
Jaemy Kim's user avatar

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