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Strange CDU Message on 737NG?!
hi everyone,
yesterday while we are cruising at FL410 strange cdu message appears on CDU which says "ICAO APPR MIS-COMPARE". I clear the scratchpad and checked the system there was no failure or something. I have checked the FCOMs, cockpit companion and mrg but couldnt find anything? do you have any idea? FlySafe! |
If the Airframe is certified for GNSS Approaches it could be a RAIM error or similar. Only active in dual- GPS/WAAS installation with neither GPS/WAAS in failure condition. Indicates that position, track or groundspeed difference between GPS/WAAS units is beyond limits. Limits are as follows: Position: Enroute Mode 4NM Terminal Mode 2NM Departure Mode .6NM IFR Approach Mode .6NM VFR Approach Mode .6NM Track: If groundspeed is greater than 30 kts, miscompare if difference is more than 4°. Groundspeed: 10 kts. just a thought. |
FDB,
I have not seen or heard of this message but in the absence of a definitive answer let us try and work it out. First we need more info, can you tell us the following? 1. What series of 737 was it and approx age? 2. What FMC update was it? 3. Do you have the IAN / GLS option enabled? 4. What airport, arrival & approach was in the FMC? 5. What freq was selected in Nav 1 & 2? 6. Where were you overflying at the time of the message? 7. Have you or your colleagues seen this message before, if so what were the circumstances & what was the fix? BTW, if this message is not documented in your company FCOMs then you should inform your Fleet/Tech Captain who will see that it is or issue some guidance. S&L |
The poor thing had hypoxia! A 737 at 41000'-cmon!!!
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please note i do not fly a FMC equipped aircraft, but from that it almost sounds like an approach that you loaded into the FMC/CDU had an incorrect "name" as opposed to the ICAO name, if you follow me
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