Thursday, 02 January 2014 16:11




We recently received an email inquiring as to the extent of the failure model on our 737 classic. About the same time, we noticed two separate flight sim forums where members inquired about failure simulation for those products also. In this blog, we discuss IXEG's position on failure simulation, where we are and what we intend to do.

Friday, 29 November 2013 16:37

737 wins again..!

B733 3

737 Wins Again

Saturday, 09 November 2013 12:03

Project Status

We are not dead!

Sunday, 07 April 2013 21:02

Jan' Flightschool


These videos are made and presented by Jan, the IXEG technical advisor on the 737. The purpose of these videos is to give you a brief introduction to the 737 classic systems if you are not already familiar with them.

Hopefully they will enable you to enjoy more of the aircraft in depth systems simulation  - ENJOY!

Monday, 11 March 2013 19:43

Autothrottle System Demo

 Jan  gives you a guided tour of the main features of the autothrottle system

 First in a series of video's on the autopilot system of the IXEG 737.

Wednesday, 05 December 2012 15:29

More Electrical

When this gets unplugged - you are on your own in terms of electricity... Then, when the engines and APU generators stop delivering electricity, it's time to get a little worried and play the one single card you have left.  That card is the battery!

Saturday, 01 September 2012 12:08

Adaptive LNAV Routing

We have almost completed our lnav route planning and during this process, we have encountered some interesting situations that we though some might find interesting.  The source data we used to construct our lnav routes comes from the database provider, Navigraph.   There are well over 300,000 waypoints in the database and thousands upon thousands of routes.  The challenge is to draw lnav routing successfully, taking into account aircraft performance and  given any potential combination of waypoint proximity and types.

There are 9 different types of waypoints in the database:  Normal, DME Intercept, Interception (INTC), Constant Heading to Altitude, VOR Radial Intercept, Vectors, PBD (Place/Bearing/Distance), Runway and Hold.   These types can appear in any order and the relative angles between waypoints can vary from zero degrees (instant reversal) to 180 degrees (no direction change).  Of course zero and 180 degree changes are special cases and not really encountered in practice, but from a theoretical point of view they exist.   In addition, the distances between waypoints can vary greatly from being very close together to very far apart.  Each case brings up unique situations that do not always demand the same results.   The figure below illustrates some of these situations.

CASE 1 shows a route whereby we takeoff and then at a VOR radial intersection we proceed along a fixed course  (097) to a DME intersection and then proceed to a normal waypoint.  The Navigraph data specifies whether a waypoint is to be flown over directly or if can be flown "by", which is in effect, "cutting the corner".    In this particular example, waypoint 3 is categorized as a "Fly-over" waypoint in the Navigraph database. This means we need to pass over the waypoint and then turn to intercept the next leg.  The normal intercept angle is 30 degrees and if waypoint is sufficiently far away, then you can indeed fly over the point and make the turn and intercept the leg between waypoints 3 and 4.   CASE 2 illustrates this.

In CASE 3 however, suppose that waypoint 4 is too close to waypoint 3 to make the turn and intercept the subsequent leg at 30 degrees (shown by the dashed line).  In this case, we must continue turning until we are flying towards waypoint 4.  If waypoint 4, which is a "flyby" waypoint is too close to our path after completing our turn from waypoint 3, then we would be forced to overfly  point 4 and then re-intercept the path away from point 4 along the route.

CASE 4 shows the same route except with waypoint 4 being a gentle turn from waypoint 3.  CASE 5 shows how if we flew the route exactly as stated in the Navigraph data, we would overfly waypoint 3 (the dashed path) and re-intercept the leg from 3 to 4.  In this case, though, because the angle is a gentle one, we can make the decision to turn a bit early and save a bit of fuel.    CASE 6 shows waypoint 4 being a bit sharper angle turn from waypoint 3 and if waypoint 3 was sufficiently close to waypoint 2, which is common in SIDs, then we would be unable to flyby waypoint 3 and would have to fly over it and re-intercept the leg to waypoint 4.

 We have written our lnav routing to be adaptive in these situations.  We look at the navigraph data, the relative geometry of nearby waypoints and in certain cases, we will change a flyover situation to a flyby and/or alter the intercept angle.  In this way we can construct the route in a more natural way as it was intended and not be completely locked in to the explicit specifications in the navigraph data, which in many cases is a "best approximation" of the procedure.  The result has been more reliable route building that better follows the published procedures and intentions of the procedure.

lnav blo

lnav blog

At this point in time, the team is deep into programming our FMS, lnav and vnav functions. Part of this process requires simulating the lateral route calculation function of the FMS given input parameters from procedures, user-entered data and the aircraft performance database.

Thursday, 19 April 2012 15:08

Hydraulics System Video


A new systems video for you.  If you have a special interest in the 737CL systems you can find schematics of the systems HERE

Tuesday, 14 February 2012 19:56

A treat for all iPhone users

Following our blog from your iPhone has just become a whole lot easier.

Tuesday, 24 January 2012 20:32


OK, here we have a CAT IIIA landing.  Dual channel autopilot.  Well the weather is offcourse not CAT IIIA ;-)  It is filmed while using track IR.  Video is raw un-edited except for compression.  So quality is reduced quite a bit.  Also turned out a bit brighter than the original - but you get the idea.  Pretty smooth..

Friday, 20 January 2012 11:44

Is it out Yet? Is it out Yet?

Hi everyone - we took a little timeout over the holidays, everyone spending some quality time with his families.

Saturday, 17 December 2011 00:00

Where is the 3D fuselage?

Many times an aircraft developer will begin his project by modeling the aircraft in 3D. Some of us have done this too — many times.

Friday, 09 December 2011 00:00


"X-Plane is the world's most comprehensive and powerful flight simulator for personal computers.With the most realistic flight model available for home users".

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