I enjoy listening to LiveATC.Net and on several occasions at different airports in the United States I have heard pilots tell the tower controller that they were making an auto landing. Is it required that pilots tell the tower controller that they are making an auto landing or is this done as a professional courtesy?
Thanks for your responses.
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Re: Auto landing - telling the tower
Essentially, it's a request from the flight to the tower to keep the ILS critical area clear (not allow a plane to be in that critical area as that aircraft may distort the ILS signal, thus preventing a successful auto-land). This is for practice auto-lands; in low visibility scenarios, the ground traffic is kept clear to begin with.
Re: Auto landing - telling the tower
Jim, pilots advising the control tower they are performing an auto-land is not necessarily a professional courtesy, but it is done to protect the integrity of the ILS signal. Remember that the localizer transmitter is at the approach end of the runway and the glideslope transmitter is at the departure end of the runway.
In addition to a hold line at the end of the runway, runways that have ILS approaches normally have an "ILS hold line" that is further back from the end of the runway than the normal runway hold line. When the weather is lower than ceiling of 800 feet or visibility less than 2 miles, the ground controller or tower controller will instruct aircraft taxiing to the runway to hold short of the ILS hold line. It may also be included in the ATIS that ILS hold line operations are in effect.
Often aircrews will perform an auto-land to maintain the certification of the aircraft and this will generally be done in Visual Meteorological Conditions. The crew advises the tower of the auto-land operation so the tower will protect the ILS critical area in weather conditions during which the tower would not normally do so. Failure to protect the ILS critical area during an auto-land could cause the auto-land to be unsuccessful.
You can get a fairly good explanation of this if you will Google "ILS critical area" and click on "Critical area (aeronautics) Wikipedia."
I hope this helps.
e38
In addition to a hold line at the end of the runway, runways that have ILS approaches normally have an "ILS hold line" that is further back from the end of the runway than the normal runway hold line. When the weather is lower than ceiling of 800 feet or visibility less than 2 miles, the ground controller or tower controller will instruct aircraft taxiing to the runway to hold short of the ILS hold line. It may also be included in the ATIS that ILS hold line operations are in effect.
Often aircrews will perform an auto-land to maintain the certification of the aircraft and this will generally be done in Visual Meteorological Conditions. The crew advises the tower of the auto-land operation so the tower will protect the ILS critical area in weather conditions during which the tower would not normally do so. Failure to protect the ILS critical area during an auto-land could cause the auto-land to be unsuccessful.
You can get a fairly good explanation of this if you will Google "ILS critical area" and click on "Critical area (aeronautics) Wikipedia."
I hope this helps.
e38
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- Florianopolis
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Re: Auto landing - telling the tower
e38 wrote:Remember that the localizer transmitter is at the approach end of the runway and the glideslope transmitter is at the departure end of the runway.
Small quibble: that's backwards.
Remember this Singapore 777 at Munich? Autoland, the departure ahead of them flew over the localizer antenna right as the 777 touched down, and the autoland rollout went crazy as the localizer deviated all over the place.
Re: Auto landing - telling the tower
Florianopolis, thank you for the correction. You are correct and I apologize for the error.
e38
e38
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