Draft ICAO Circular on NLA.pdf - Airports Council International

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Paragraph 5.2.4: Attention should also be paid when designing shoulders to prevent the
ingestion of stones or other objects by turbine engines.
Paragraph 5.2.5: In case of special preparation, visual contrast between runway and runway
shoulders may be needed.
4.1.2.6 Hazard identification and analysis
4.1.2.6.1 Runway shoulders have three main functions:
a) to support occasional aircraft incursions without inducing structural damage to the
aeroplane;
b) to provide jet blast protection and to prevent engine ingestion; and
c) to support ground vehicle traffic (RFF vehicles in particular).
4.1.2.6.2 Potential hazards associated with runway shoulder characteristics (width, soil type, bearing
strength) are:
a) aircraft damage that could occur, due to inadequate bearing capacity, after incursion
onto runway shoulder;
b) shoulder erosion causing ingestion of foreign objects by jet engines due to unsealed
surfaces; and
c) difficulties for RFF services to access a damaged aircraft on the runway due to
inadequate bearing strength or width.
4.1.2.6.3 Main causes and accident factors are:
a) runway centre line deviations (see runway excursion risk);
b) power plant characteristics (engine height, location and power); and
c) inadequate shoulder width, soil type, and bearing strength.
4.1.2.6.4 The specific NLA issues of concern to the RFF vehicle traffic are:
a) aeroplane wing span, engine position, escape chute extension length; and
b) shoulder width and bearing strength.
4.1.2.6.5 Certification requirements define the impact of foreign object damage (FOD) risks on aircraft
tires and engines as potentially major. Delay in RFF operations could be classified as major to catastrophic.
Sudden deceleration resulting from heavy braking, or due to aircraft damage can cause injuries that could
be classified as major or catastrophic.
<strong>ICAO</strong> Version 4.1 — 15 March 2004