Odd G-III question

RotorAndWing said:
Honestly I can't see the usefulness of timing a takeoff roll.

We start the chrono on the ND at application of takeoff thrust but that's for a different purpose.
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This is NOT a flying question, this is a risk analysis. Let's say you have something hazardous on board the G-III that could cause harm to people on the ground. (The occupants on the plane would be assumed to be under informed consent and are not of concern, but the uninvolved people on the ground need to be considered.) We need to determine the period of time the people along the runway would be exposed to that hazard, so we can do a risk analysis that assesses the probability of them being affected by the hazard, given certain parameters regarding vehicle reliability. Regulations in place require that the calculated risk be below a certain threshold, so the amount of time it takes for the "hazard" to pass is one of the components that determines the overall exposure.
 
Since someone beat me to the treadmill comment, I'll give a straight answer.

Short of flight testing your best bet is going to be to get a flight manual and assume standard day, dry level paved runway, and max gross weight takeoff parameters. This will give you the takeoff distance and rotation speed. Liftoff will occur probably less than 5 seconds after rotation.

Now just assume constant acceleration from zero to rotation and use the formulas already presented.

That will be close enough for government work.
 
Ken Ibold said:
This is NOT a flying question, this is a risk analysis. Let's say you have something hazardous on board the G-III that could cause harm to people on the ground. (The occupants on the plane would be assumed to be under informed consent and are not of concern, but the uninvolved people on the ground need to be considered.) We need to determine the period of time the people along the runway would be exposed to that hazard, so we can do a risk analysis that assesses the probability of them being affected by the hazard, given certain parameters regarding vehicle reliability. Regulations in place require that the calculated risk be below a certain threshold, so the amount of time it takes for the "hazard" to pass is one of the components that determines the overall exposure.
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Uhh ohh, we're gonna nuke Syria from a G-III:lol:
 
Ken Ibold said:
This is NOT a flying question, this is a risk analysis. Let's say you have something hazardous on board the G-III that could cause harm to people on the ground. (The occupants on the plane would be assumed to be under informed consent and are not of concern, but the uninvolved people on the ground need to be considered.) We need to determine the period of time the people along the runway would be exposed to that hazard, so we can do a risk analysis that assesses the probability of them being affected by the hazard, given certain parameters regarding vehicle reliability. Regulations in place require that the calculated risk be below a certain threshold, so the amount of time it takes for the "hazard" to pass is one of the components that determines the overall exposure.
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Does it also include taxi time, loading time, time for it to get to the airport, time for it to get to the GIII once at the airport? The biggest risk on this isn't when the GIII is rolling, it's everything up to and after that point. Unless they are actually manufacturing it on the GIII and only when holding short....sorry, lining up and waiting.
 
EdFred said:
Does it also include taxi time, loading time, time for it to get to the airport, time for it to get to the GIII once at the airport? The biggest risk on this isn't when the GIII is rolling, it's everything up to and after that point. Unless they are actually manufacturing it on the GIII and only when holding short....sorry, lining up and waiting.
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All that is handled separately using standard DoD separation distances determined by the class of the hazard and the net equivalent weight. Except for the line up and wait. That would not apply as the aircraft is cleared for takeoff prior to the hazard existing.
 
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