There are a handful of signs you'll see on the rest of your journey around the airport, destination signs, information signs, and an assortment of other location and mandatory hold position signs.

ILS Critical Area Holding Position Sign

As mentioned in the Runway Signage lesson, there are cases where a pilot must hold short of a runway at a location displaced from the runway threshold entrance in order to avoid disrupting aircraft operating on the active runway. At airports with instrument landing operations, there may be times when aircraft movement near the active runway would cause interference in the instrument landing system (ILS). At these times, movement in the ILS Critical Area is strictly prohibited.

The ILS Critical Area will be marked by an ILS Critical Area Holding Position Sign, as well as by additional markings on the ground (covered in the airport markings lesson). The sign will be mandatory in nature, red with white lettering, and will state "ILS".

Keep in mind that the ILS critical area is not always active, but when the control tower advises you the area is active, you must not pass the ILS Holding Sign until cleared to do so. If you are approaching the ILS critical area and are in doubt as to whether it is currently in use, ask the tower to clarify if you may proceed.


The ILS Critical Area Holding Position Sign

ILS Critical Area Boundary Sign

Just as there are warnings to pilots approaching an ILS critical area, there are also signs informing pilots exiting the runway that they are clear of the ILS critical area. When these signs are present, ensure that your aircraft is all the way on the taxiway side past this sign and any associated ground markings before halting your movement. If you do not pass this sign you are not clear of the ILS critical area and may be disrupting or prohibiting incoming traffic from using the instrument landing system.

ils critical area

ILS Critical Area Boundary Sign

No Entry Sign

Just as it implies, this sign is present at areas where no aircraft entry is permitted. This sign may be located to show a taxiway as being one direction only, or at an area where pavement intended for non-aircraft usage abuts  a taxiway. Note that due to its coloration, this sign is considered mandatory in nature and must be complied with.

No entry

Destination Signs

Think of a destination sign like those signs on the freeway that show what amenities are coming up at the next town. Destination signs can indicate directions for aircraft leaving or arriving at an airport. All destination signs are yellow with black lettering. Outbound signs will show a runway or taxiway designator, and an arrow indicating the direction of taxi to reach the stated destination. Inbound destination signs will point arriving traffic towards the terminal, FBO, transient parking, cargo area, military area, or any other pertinent destinations around the airport. If the sign indicates two areas that share a common taxiway, the designators will be separated by a dot. For example, in the image below on the left, runways 27 and 33 can be reached by making aright turn on the indicated taxiway.

Destination sign showing common taxiway for two runways

Destination sign showing common taxiway for two runways

Destination sign for military area

Destination sign for military area

Information Signs

Information signs are also yellow with a black inscription. Information signs give pilot pertinent instructions that are necessary to know and may have been forgotten to be researched in the preflight planning. Radials to rune to may be posted at a VOR checkpoint, a noise abatement procedure may be posted on an information sign in the runup area or at a runway hold short sign, or a sign telling a pilot to change to another frequency (i.e. tower or ground) may be present in an area where aircraft commonly lose radio contact with the controlling authority.


An information sign may remind a pilot to change to tower frequency at a certain point on the airport

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