48 Hour Forecast
48hr

12 Hour Forecast
12hr


36 Hour Forecast
36hr

    (AERODATA 1.7.16)     (JeppFD 3.1.7)     (MyMobile365 2.9.1)     (IOS 11.4.1)    (Airwatch 5.7.2)     (AQD 2.4.6)      (WSI 2.13.1)     (JETCRW 1.3.0)

24 Hour Forecast
24hr

Little Known Facts

Little Known Facts Archive


The BlueBrief home page sometimes displays topics that I feel are not completely understood or known.
The following is an archive of those past topics.

Remember, your FOM / FCOM always has priority.


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.3 RNP & RNAV Visuals - A320/321

Remember, for RNAV Visuals, it is not required to enter .3 RNP on the Prog page during the setup, unless ".3 RNP Required" is shown on the Approach Chart.  Entering the .3 RNP, simply triggers the "Accuracy Low. GPS Primary Lost" message.  On all RNP Approaches, and selected RNAV Approaches in some cases, this would require a Missed Approach, but not on an RNAV Visual.

Bottom line ... .3 RNP is required on any RNAV or RNP Instrument Approach.  The RNAV Visual is not an instrument approach.


Lowest Usable Flight Levels


Here's a really useless fact.
On the CAMRN # Arrival into JFK, there is a note that we all know about.  Expect to cross HOGGS at FL180 or the lowest usable Flight Level.

When the altimeter setting is below 29.92, FL180 is not usable, so we use FL190. The little known part is that this is based on the altimeter setting at ACY, not JFK. So, during your setup, and the JFK Altimeter setting is close to 29.92,  if you want to be a step ahead, check the ACY ATIS for the final decision or to avoid some confusion.


Landing and Takeoff Data
Wet or Dry?


This not really a little known fact, but worth thinking about.  For Takeoff, Aerodata defaults to a DRY runway, and you must manually select WET for a wet runway, but the TLR numbers are based on a WET Runway, should you need to use those.  For Landing, it's just the opposite ... Aerodata defaults to a WET Runway, (RCC=5) and you must select DRY (RCC=6), if you need dry numbers.  It is perfectly OK to use WET numbers on a DRY runway for landing, but keep in mind you have the option of forcing it to DRY, RCC=6 if needed for a short runway, at max landing wt, on a hot day, for example.