When i activate the lnav on b738, the autopilot doesn’t follow the route. Is this a bug?

Question

I have activated everything correctly and made the flight plan following the instructions on the manual and viewing some videos where everything went correctly. After take off I set the speed, the vs an the lnav... Suddenly the airplane turn and and the speed and the climbing angle change. At the end the airplane crashes. Is all of this a bug or I am forgetting something? Please help me.

Comments

Could it be you turned on the Flight director, but not the auto-pilot?

Answer 1

Hi Omar0167

I'm not with Laminar Research, just a fellow simmer in the UK :-)

Not being quite sure what your intended method of navigation is with the 737-800, but this is what I do to ensure that the aircraft follows the programmed flight plan.

1. Program the flight management computer (FMC) correctly with a valid route, obtained from Simbrief or similar

2. Initially set pilot/co-pilot HSI OBS & autopilot course to that of take off runway

3. Set autopilot airspeed to 140 knots, or as indicated by FMC

4. Set autopilot altitude to desired maximum flight level

5. Turn on flight director switches on pilot & co-pilot side

6. Turn on auto throttle switch on pilot side

7. Press LNAV & VNAV buttons so that they light up

8. Initially take off manually with 10 - 20 degree rate of climb, also manually following route on flight display map

9. Shortly after take off & wheels up, select autopilot engage CMD A button and the aircraft should then follow the flight plan programmed into the FMC.

Hope this helps

Regards