Author: jhbehrens
Subject: FMS gotcha
Posted: 02 Nov 2015 at 5:43am
This weekend I experience some unexpected behaviour of my IFD540 which I am sure is by design.
Edited by jhbehrens - Yesterday at 5:45am
Subject: FMS gotcha
Posted: 02 Nov 2015 at 5:43am
This weekend I experience some unexpected behaviour of my IFD540 which I am sure is by design.
I was about to depart IFR from an airport with low visibility. My filed route involved a direct to a waypoint to pick up an airway. I had programmed this route and activated the flight plan.
When I received my clearance I was given a SID. I then went into the FMS and added the departure to the departure airport.
During take-off into IMC at about 500 ft I switched on GPSS on my Aspen and pushed the HDG button of my 55x. To my surprise the aircraft turned towards the original initial waypoint and did not fly the departure as I had expected. I pressed direct to the final fix at the end of the departure which sort of fixed the situation as I could work out fast enough which intermediate step in the departure to select based on where I was.
I assume what happened is that when I activated the flight plan the IFD made the segment to the original fix active. When I later added a departure sequence in between the airport and that fix (which I didn't remove) it was just skipped over by the FMS.
I wanted to alert others to this 'gotcha' to which I am sure people will respond saying is by design but that really surprised me and in less forgiving terrain could have been potentially dangerous.
Jorgen
Edited by jhbehrens - Yesterday at 5:45am