FMC not working
I have had this fantastic aircraft for some time now and I never get the FMC to wo work. I enter the waypoints from PRO-ATC flight plan. So far so good. I then come to the Fuel page I enter the data from the Bea 146 Load Manager. First problem. Although I have set my fuel level to 25% more than the load manager recommended. The FMC says I do not have enough fuel so does not show any reserves or fuel overhead at destination. But I carry on and input Perf data ie Cruise altitude. I then fly but the FMC does not move the magenta from the first waypoint. What am I doing wrong or not doing? Yes I know it's madness to keep doing the same thing and expecting a different outcome.
@old-john Hi John, not an expert by any stretch, and I don't work for, or represent JF, but I have racked up a few virtual hours in the BAe 146 now and may be able to assist.
Some observations on fuel planning. I don't use the JF fuel planner, but having tried an example trip in the 146-100, I've noticed the distance quoted (and thus fuel calculated) is based on a straight line between origin and destination. It's therefore worth keeping in mind it doesn't take into account any of the route variations PRO-ATC or other planning software may throw up, the altitude at which you're flying (which can have a significant impact on fuel burn) nor does it consider wind direction and strength.
As an example, Newcastle to Heathrow (EGNT-EGLL) is, according to the JF planner, 218 nautical miles - correct as the crow flies, but putting the same origin and destination into Pro-ATC (or Simbrief) gives me a distance of 230nm (routing via airways so there's a slight dogleg - UP18 to Pole Hill, and then N57 to LHR - rather than flying direct).
Don't forget you'll also burn additional fuel taxiing at both ends, during departure and arrival procedures, and on approaches which add extra track miles to your flight.
To give you an idea, the JF planner estimates you'll need 1017 US Gal for this trip (around 6,820lbs). By comparison, the excellent (and free!) Simbrief (www.simbrief.com) calculates the required fuel for the same trip to be 7,850lbs (including fuel for taxiing).
If you want to crank up the realism a little more, you may also want to factor in a wee contingency (2,000lbs), fuel to reach your alternate in the event you have to divert (in this case, 4,000lbs to get to back to Manchester), and a final reserve (allowing for up to 30 minutes holding) of 2,400-ish lbs. According to Simbrief, adding all of these takes your fuel requirement up for this trip up to a whopping 16,330lbs. This may go some way to explaining the discrepancy between the JF flight planner and the FMC?
Speaking of the FMC , I'm not entirely sure I grasp your issue - by which I mean I understand the problem you're describing, I just don't understand why you're having it. To give you an idea of my process, I tee up a flightplan in the FMC (based on Pro-ATC, Simbrief etc), check the NAV page to ensure the 'from' and 'to' waypoints are correct and flip the HSI switch on the main panel (it's the yellow switch above the standby attitude indicator) up to R NAV to give me direction and distance to the waypoint - as long as you overfly the waypoint the FMC should advance automatically to the next entry in your flightplan. This appears to work irrespective of whether you're hand flying, in a direct autopilot mode (such as HDG hold) or flying with LNAV selected.
As an experiment, try this: Place the aircraft on Runway 07 at Newcastle (EGNT). Create a flightplan on the FPL page of the FMC as follows: EGNT > DIGBI > NATEB > EGNT
Check the NAV page; 'from' should show as EGNT and 'to' in magenta should say DIGBI.
Setting the HSI to R NAV will give you direction and distance to the DIGBI - it's directly ahead of you and just offshore so take off from Runway 07 and climb straight ahead. Once you overfly this waypoint, it should automatically update to NATEB - if you're hand flying or in autopilot and using HDG mode, you'll need to make the turn to the next waypoint, but if you're in LNAV it should do so for you. Does this happen for you?
Hope this helps!
Firstly, let me thank you for answering my post. The fuel problem. I have always put about 25% extra in. But since your suggestions I have put 50% extra in and the FMC likes it.
The waypoint problem I think is PRO-ATC's fault (more experiments needed to prove it). Today I flew from EGJJ Jersey to EGNX East Midlands. There are only 2 way points on route JSY & BZN then EGNX. I used P3D's default ATC (not realistic enough for me but) I flew most of the flight in LNAV and the FMC liked it. More tests needed to 100% crack this thing. Once again thanks for the help.