I'd like to add to this, as I posted the last bug report for taxi collisions. I did ten tests, and these are my findings:
TASK: Launch into an airfield orbit:
1. 4 SU-25's (on runway for takeoff)
2. 4 Su-27's (from parking space)
3. 3 MiG-29A's (from ramp start)
4. A-50 Awacs
NOTE: TEST 1 SETUP (DEFAULT/CONTROL TEST) WORKS IN DCS WORLD 1.2
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TEST 1: Normal launch from Maykop airfield. Su-27's are closest to runway, followed by A-50, then MiG-29's:
- RESULT: MiG-29A #2 becomes 'hung' on taxiway at corner and refuses to move, holding up Mig-29A #3 & A-50.
- NOTES:
1. Traffic is bunched up and stop-and-go.
2. Despite A-50 being closer to runway than MiG-29's, the 29's move in front of the A-50 to takeoff first. (ATC decision or bug?)
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TEST 2: Maykop launch, MiG-29's moved to parking spaces FURTHER from runway:
- RESULT: ALL AIRCRAFT TAKEOFF.
- NOTES:
1. A-50 taxi's to takeoff before MiG-29A's as it is closer and enters taxiway first.
2. Traffic still becomes bunched and stop-and-go near the final turn to the runway.
3. Aircraft do not seem to care in this instance.
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TEST 3: Maykop launch, MiG-29's moved to parking spaces CLOSER to runway:
- RESULT: COMPLETE MESS!
- NOTES: UNUSUAL ORDER!
1. The A-50 starts to move first, followed by the Su-27's, which fall into line behind it.
2. MiG-29A #1 manages to get started up and enters the taxiway abruptly, nearly cutting off the A-50 in the process.
3. A-50 goes 'braindead' while 29 #1 continues to taxi.
4. 29 #2 abruptly attempts to enter taxiway as SU-27 #1 is taxiing past.
5. 29 #2 collides with 27 #1. No fire or ejection.
6. A-50 eventually starts moving again to takeoff.
7. 29 #3 is parked closer to the runway than #2. Despite its path being unobstructed, it refuses to taxi to takeoff because #2 has skewered the SU-27
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TEST 4: SAME AS TEST 3 but MiG-29's are changed to SU-27's in new parking order.
- RESULT: SAME AS #3 with the exception of the skewered aircraft causing an explosion due to the SU-27's extra length.
- NOTES: Same unusual 'rush' to get to the runway as test #3.
TRACK 4
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TEST 5: SAME AS TEST 4 but new Su-27 3-ship (former Mig-29's) initual state changed to takeoff from parking spot (rather than ramp startup). New group ordered logically (1 closest to runway, 2 in the middle, 3 furthest of 3ship).
- RESULT: ALL AIRCRAFT TAKEOFF.
- NOTES: All aircraft fall into line orderly. Traffic is stop-and-go. A-50 waits to go last.
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TEST 6: SAME AS TEST 5 but new Su-27 3ship numbers 2 and 3 are swapped. (1 is closest to runway, 2 is furthest of group from runway, 3 is in the middle.
- RESULT: ALL AIRCRAFT TAKEOFF.
- NOTES:
1. The middle aircraft (#3) waits for #2 to pass before following behind.
2. The A-50 waits for the 4-ship of Su-27's to pass before falling into line behind them, despite being closer to the runway than all four.
3. Traffic once again is stop-and-go.
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TEST 7: Su-27 4-ship initial state changed to Ramp Start.
- RESULT: NONE OF THE PARKED AIRCRAFT TAKEOFF. 2 FATALITIES.
- NOTES:
1. A-50 moves first (state is takeoff from park, NOT ramp start).
2. Mig-29A # 1 follows behind (OTHERS DO NOT).
3. Su-27 #'s 1 and 2 start up and collide with each other head-on while coming out into the taxiway. After this, everybody behind them freezes.
4. #3 and #4 do not move out of their spaces, nor Mig-29A's #2 and #3.
TRACK 7
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TEST 8: ALL parked aircraft set to Ramp Start
- RESULT: ONLY 3 AIRCRAFT TAKEOFF (2 Su-27's, A-50).
- NOTES:
1. Unusual order: Su-27 #1, Su-27 #2 (No collision), A-50, Mig-29 #1, Mig-29 #2, Su-27 #4.
2. A-50 waits almost 45 seconds to move again after Su-27 #2 pulls out.
3. Su-27 # 3 and Mig-29 # 3 remain parked
4. MIG-29 # 1 STOPS MOVING AFTER IT HAS TO STOP FOR A-50 AND HOLDS 4 OTHER AIRCRAFT BEHIND IT INDEFINITELY.
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TEST 9: ALL parked aircraft set to Ramp Start, A-50 parking spot swapped with Su-27 #4 (Now lot 54 instead of 54). Entire SU-27 4-ship is now in the closest lots to the runway, followed by the A-50, followed by 3-ship Mig-29's.
- RESULT: ONLY 3 AIRCRAFT TAKEOFF: 2 Su-27's (1 & 2) and A-50.
- NOTES:
1. All lead aircraft move first (su-27 #1 and A-50 at the same time followed by Mig-29 #1)
2. A-50 (2nd in line behind Su-27 #1 stops for Su-27 #2 and gives the right of way.
3. A-50 waits 3 minutes before taxiing again.
4. Su-27 #4 pulls in behind Mig-29 #2 (Su-27 #3 is still parked)
5. Mig-29 #1 refuses to move after coming to a stop behind A-50, halting all other aircraft indefinitely.
TRACK 9
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TEST 10: Moving all units to Krymsk airfield and not altering listed parking spots or start conditions from original:
- RESULT: ALL AIRCRAFT TAKEOFF.
- NOTES: Traffic is smooth and spaced far apart. No plane has to stop its taxi due to an obstruction in front.
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// CONCLUSIONS:
1. There is something wrong with the ATC logic for aircraft taking off from ramp/cold starts. ATC doesn't seem to know how to handle aircraft that aren't already running. This may be due to the timing of taxi permissions given by ATC with regards to the aircraft's startup. In some cases, it seems that ATC gives the aircraft permission to taxi as soon as the aircraft is fully started up, regardless of traffic (See test 7)
2. There may be something wrong with ATC logic for taxiing groups of aircraft out of order (Either within a group or different aircraft groups mixed together). However, this may be confounded by the ramp start issue.
3. Stop-and-go traffic seems inconsequential.
4. When all aircraft are set to takeoff from parking rather than ramp start, there are no collisions or hang-up's regardless of order or location.
5. The only way to avoid a collisions with aircraft taking off from Ramp Start is to move them far enough away from other aircraft that they have no ATC hold or traffic conflicts.
Computer specs
