Questions & Answers
Q. Barry White – How are sign foundations normally protected by delethalisation ie by concrete or sub-base material
A. Sign Foundations are generally of a structure ( eg. concrete) of sufficient strength to ensure that the wid loadings ( natural or from jet balst ) so that the sign themselves remain fixed & stable. Additionally, all structures shall be delethalised in the Obstacle Free Zone so that should an aircraft depart the runway or taxiway pavement ( albeit the signs themselves are installed on frangible couplings at foundation level) the base units/foundation shall also provide such protection. hence delethalised. Details are available in the respective ICAO Aerodrome Design Manual.
Q. Barry White – Thanks Keith but I do not think ADM states that concrete should be used for the dewlethalisation ramp
A. No, I agree …. but I only used ‘concrete’ as one solution for a foundation as being a ‘structure of suitable composition & strength’
Q. Barry White – If a information sign has a straight ahead directionshould the straight ahead arrow to the left or right of location sign
The Location sign is installed to the outboard side to the Direction sign in this regard whether installed to the right or left of the respective taxiway.
Q. Aasif Bapoo – What is the basis for tilting signs in terms of best practice…Annex 14 doesnt provide clear guidance on this but other standards like MoS 139 requires all signs to be angled. FAA also has some guidance in this regard.
A. Correct …. little guidance on this subject is available from ICAO where it is given that in ICAO SARPS that Guidance Signs (MAGS) are installed perpendicular to the runway or taxiway centreline. However, since SARPs was last updated regarding installation orientation for MAGS, aircraft have developed, & git bigger, engine pods hang over the edge of Runways or Taxiways, jet blast effect is nowadays important. Hence the reasoning for the angular installation guidance for MAGS to deflect j=their jet blast and reduce the wind loading directly on a MAGS. It is the FAA in the US who have issued further guidance in this respect !
Q. Anonymous Attendee – Gap between the signs in the adjoining two boards shall be as per guidelines or any deviations permitted in maintaining sane
A. ICAO Annex 14 refers.
Q. Alexander Suprunov – Where I can find requirements for VOR signs, like font style, size of symbols etc.? Thanks
A. A VOR sign is a Guidance Sign. Hence same details as in Annex 14.
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