Hi all,
I now have my first AI aircraft flying out of Melbourne's Tullamarine
airport (ICAO = YMML) to Sydney's Mascot airport (ICAO = YSSY). Many
thanks to Durk for his assistance.
Some observations about the AI aircraft's flight:
The aeroplane was airborne at about one-third along the length of the
runway. A real 737 needs most of the runway to reach its rotation point.
The landing gear doesn't retract. This is a minor quibble, but I noticed
that the AI 737-300 aircraft model includes separate components for the
landing gear. I was hoping that the AI aircraft could be animated to
retract the landing gear after take-off. Likewise, the engine's turbines
don't spin. Are there any plans to animate AI aircraft?
YMML runway 27 is on heading 274 degrees. The AI aircraft maintained
this bearing until about three minutes into the flight, at 9,000 feet.
Real-life Melbourne-to-Sydney aeroplanes turn right before the landing
gear has fully retracted. (Heck, I've been on flights where turn starts
before the landing gear has left the tarmac! You get a really good view
of some horses in the paddock outside the airport boundary.) Are
FlightGear's AI pilots more conservative than real-life ones?
The aeroplane climbed slowly to about 3,300 feet, then started to climb
rapidly to about 9,000 feet. It turned to bearing 065, which is the
route to Sydney, and continued to climb. I tried this several times, and
once the AI aircraft performed a 210-degree /left/ turn instead of a
150-degree /right/ turn toward Sydney. Why would it do that?
Has anyone ever watched an AI aircraft make a landing? I wanted to watch
the AI aircraft on its flight to Sydney. I thought this would be easy
with the FlightGear's "time warp" function. However, I discovered that
AI aircraft are not subject to FlightGear's timewarp (effectively, the
AI aircraft slows down when time speeds up). If time is running faster
shouldn't the AI aircraft also travel faster in order to maintain their
landing schedules?
This means that I could not accelerate FlightGear to watch the AI
aircraft land in Sydney. Instead, I started FlightGear with the command
fgfs --airport=YSSY --aircraft=ufo --start-date-gmt=2008:05:03:03:55
(That is, at Sydney airport five minute before the flight landed.) I
searched around with the UFO, and found the AI aircraft still at 30,000
feet at 0400 UTC, when it should have been about to land in Sydney. I
followed it on heading 069 until 0413 hrs, by which time it was about
100 km out over the Pacific ocean. At that time, it made a 180-degree
turn and went into a 35-degree dive, which would have been exciting for
all concerned. It levelled-out at ~8,500 feet on heading 254. It held
that course while it made a slow descent into Sydney. The flight
touched-down (after flying through some ground scenery) at~0430hrs -- 30
minutes after its scheduled arrival time. It taxied to the end of the
runway.
I haven't created a ground network for Sydney, and because of
Melbourne/Sydney rivalry I'm not going to :-) . The aircraft taxied
cross-country on a beeline to Sydney airport's origin, where it turned
around a couple of times like a dog trying to lie down!
By now the time had passed the departure time for the return trip back
to Melbourne. The AI aeroplane made a couple of consecutive
push-back-and-forward moves (it never actually came to a full stop),
then turned to heading 244 and started to taxi towards Melbourne. I
stopped the simulation when I realised the plane was happy to taxi
across Sydney harbour.
Does that behaviour seem odd to anyone else?
I started FlightGear again, with the command:
fgfs --airport=YSSY --aircraft=ufo --start-date-gmt=2008:05:03:04:25
(That is, Sydney airport five minutes before departing for the return
trip.) The aircraft was on the ground at the airport's origin, as
expected. Sure enough, at 04:30 it pushed-back, taxied to the runway and
took off. By the way, while the 737 was at the start of the Sydney
runway two light aircraft, about 100m apart, approached and landed
/through/ it. This would be cause for some excitement in real life. Is
ATC asleep in FlightGear?
I started FlightGear with the command
fgfs --airport=YMML --aircraft=ufo --start-date-gmt=2008:05:03:05:55
(That is, Melbourne airport five minutes before the return trip landed.)
I found the AI aircraft at 31,000 feet on heading 110. I followed it for
another few minutes, until it went into another 35-degree dive from
31,000 to 8,000 feet. Who says a 737 can't do aerobatics? It descended
very slowly from 8,000 feet, heading 274, until it touched-down at YMML
at 0622 hrs -- 22 minutes after the scheduled arrival time.
Do the AI aircraft always arrive late at their destinations?
After the AI aircraft landed at YMML, FlightGear crashed with a
segmentation fault and core dump. This may be because my very simple
ground network has no nodes to taxi off the runway after landing. I will
continue to investigate.
Regards,
Greg Hawkes
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