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Work in progress distance from runway

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Work in progress distance from runway

Old 20th Apr 2017, 19:22
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Work in progress distance from runway

A holding point or holding position distance from the Runway centerline that has a precision approach CAT I, II, or III and is code 4F is 107.5 meters (According to ICAO Annex 14 volume 1 chapter 3.12.6). Also, ICAO Annex 14 chapter 3.4.7 states that:
"No fixed object, other than visual aids required for air navigation purposes and satisfying the relevant frangibility requirement in Chapter 5, shall be permitted on a runway strip:
a) within 77.5 m of the runway centre line of a precision approach runway category I, II or III where the code number is 4 and the code letter is F;
No mobile object shall be permitted on this part of the runway strip during the use of the runway for landing or take-off."

Now with that being said, can a work in process that includes trucks, vehicles, and personnel work at a distance greater than 77.5 meters from runway centerline (lets say at 80 or 85 meters from cl) for CAT I 4F while the runway is active and is used for take offs and landings, and just have the Tower or ATIS provide information to pilots about the work in process that's going on?
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Old 22nd Apr 2017, 19:58
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The 107.5m for Cat I, II and III is a minimum distance. It may need to be more to avoid interference to the ILS signal.
You can carry out work outside of 77.5m from the runway centreline on a Code 4 F runway provided it is a non-precision or non instrument approach where a minimum 75m from
runway centreline applies provided the visibility and cloud ceiling permits arriving aircraft to operate visually. As you say provide the works information to pilots via ATIS or radio comms. Also a Notam could be issued.
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Old 22nd Apr 2017, 21:48
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In the UK it depends on the width of the OFZ (Obstacle Free Zone) which in turn depends on the code of the runwway and whether it is a VFR or IFR runway.
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Old 23rd Apr 2017, 20:25
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The reason why I'm asking is because at OBBI we have this instruction that work in process can be carried out 77.5 meters or more from runway centerline. The runway at OBBI is code 4 letter F and ILS CAT I and a most pilots here perform precision approach to land. In this case if theres a work in process wouldn't it interfere with the ILS signal for precision approach landing or cause distortion or attenuation?
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Old 24th Apr 2017, 16:21
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People are frangible at least...
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Old 24th Apr 2017, 17:56
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It's unlikely that work in progress 77.5m from runway centreline would interfere with ILS Cat I signals as the ILS protected area is much smaller for Cat I equipment when compared to Cat II/II. If the work takes place in good weather conditions then there shouldn't be a problem. If weather deteriorates then the work should stop and everyone + equipment clear the area for their own safety as well as aircraft safety.
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Old 24th Apr 2017, 18:16
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Originally Posted by Musket90 View Post
It's unlikely that work in progress 77.5m from runway centreline would interfere with ILS Cat I signals as the ILS protected area is much smaller for Cat I equipment when compared to Cat II/II. If the work takes place in good weather conditions then there shouldn't be a problem. If weather deteriorates then the work should stop and everyone + equipment clear the area for their own safety as well as aircraft safety.
It could easily affect the glidepath signal if it takes place in the beam forming area in front of the antenna.
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Old 25th Apr 2017, 08:27
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Two separate issues: risk to aircraft and people near the runway due to proximity to each other, and interference to the ILS signal.You cannot have anyone work inside the 77.5 during landings and takeoff. You can have people inside the strip (the 150m marked area), up to 77.5 from the C/L, with mitigations. You cannot have vehicles inside the strip during a/c operations.
In the case of OBBI, the protected area is inside the strip. You wouldn't walk in front of the antenna whilst radiating, as there are signs warning you of the radiation hazard in the relevant area, and I doubt that a person would distort the signal. It's a CAT II ILS rated at CAT I due to the inability to protect the protected area outside of the strip.
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Old 25th Apr 2017, 18:41
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Yes - Chevvron is correct. I forgot to mention that ILS Localiser and Glidepath have "critical areas" which should be marked and any work inside these areas will affect the integrity of the radio signals. So if work is needed, such as grass cutting within these areas, then it should be done when the ILS is switched off and not in use.
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