Chapter 10 Aerodrome Maintenance November 18 ICAO Annex 14 Training Course
Chapter 10 Aerodrome Maintenance 10.1 General Recommendations.— A maintenance programme, including preventive maintenance where appropriate, should be established at an aerodrome to maintain facilities in a condition which does not impair the safety, regularity or efficiency of air navigation. “Preventive maintenance” is programmed maintenance work done in order to prevent a failure or degradation of facilities. “Facilities” are intended to include such items as pavements, visual aids, fencing, drainage systems and buildings. The design and application of the maintenance programme should observe Human Factors principles. [ICAO Human Factors Training Manual] 10.1 General 10.1.1 Recommendation.— A maintenance programme, including preventive maintenance where appropriate, should be established at an aerodrome to maintain facilities in a condition which does not impair the safety, regularity or efficiency of air navigation. Note 1.— Preventive maintenance is programmed maintenance work done in order to prevent a failure or degradation of facilities. Note 2.— “Facilities” are intended to include such items as pavements, visual aids, fencing, drainage systems and buildings. 10.1.2 Recommendation. — The design and application of the maintenance programme should observe Human Factors principles. Note.— Guidance material on Human Factors principles can be found in the Human Factors Training Manual. November 18 ICAO Annex 14 Training Course
Chapter 10 Aerodrome Maintenance 10.2 Pavements Surface irregularities Recommendations.— The surface of pavements (runways, taxiways, aprons, etc.) should be kept clear of any loose stones or other objects that might cause damage to aircraft structures or engines, or impair the operation of aircraft systems. The surface of a runway should be maintained in a condition such as to preclude formation of harmful irregularities: Max. 3mm tolerance of the newly built wearing course is permitted; In general, isolated irregularities of the order of 2.5 cm to 3 cm over a 45 m distance are tolerable; Surface irregularities 10.2 Pavements 10.2.1 Recommendation.— The surface of pavements (runways, taxiways, aprons, etc.) should be kept clear of any loose stones or other objects that might cause damage to aircraft structures or engines, or impair the operation of aircraft systems. Note.— Guidance on precautions to be taken in regard to the surface of shoulders is given in Attachment A, Section 8, and the Aerodrome Design Manual, Part 2. 10.2.2 Recommendation.— The surface of a runway should be maintained in a condition such as to preclude formation of harmful irregularities. Note.— See Attachment A, Section 5. [Attachment A, Section 5.] 5. Runway surface evenness 5.1 In adopting tolerances for runway surface irregularities, the following standard of construction is achievable for short distances of 3 m and conforms to good engineering practice: Except across the crown of a camber or across drainage channels, the finished surface of the wearing course is to be of such regularity that, when tested with a 3 m straightedge placed anywhere in any direction on the surface, there is no deviation greater than 3 mm between the bottom of the straight-edge and the surface of the pavement anywhere along the straight edge. 5.2 Caution should also be exercised when inserting runway lights or drainage grilles in runway surfaces to ensure that adequate smoothness of the surface is maintained. 5.3 The operation of aircraft and differential settlement of surface foundations will eventually lead to increases in surface irregularities. Small deviations in the above tolerances will not seriously hamper aircraft operations. In general, isolated irregularities of the order of 2.5 cm to 3 cm over a 45 m distance are tolerable. Exact information of the maximum acceptable deviation can not be given, as it varies with the type and speed of an aircraft. 5.4 Deformation of the runway with time may also increase the possibility of the formation of water pools. Pools as shallow as approximately 3 mm in depth, particularly if they are located where they are likely to be encountered at high speed by landing aeroplanes, can induce aquaplaning, which can then be sustained on a wet runway by a much shallower depth of water. Improved guidance regarding the significant length and depth of pools relative to aquaplaning is the subject of further research. It is, of course, especially necessary to prevent pools from forming whenever there is a possibility that they might become frozen. November 18 ICAO Annex 14 Training Course
Chapter 10 Aerodrome Maintenance 10.2 Pavements Friction characteristics Measurements of the friction characteristics of a runway surface shall be made periodically with a continuous friction measuring device using self-wetting features (i.e. Mu-meter Trailer, Skiddometer Trailer, Runway Friction Tester Vehicle). The friction of a wet paved runway should be measured: to verify the friction characteristics of new or resurfaced paved runways when wet; to assess periodically the slipperiness of paved runways when wet; to determine the effect on friction when drainage characteristics are poor; and to determine the friction of paved runways that become slippery under unusual conditions (eg. after a long dry period). 10.2 Pavements Friction characteristics 10.2.3 Measurements of the friction characteristics of a runway surface shall be made periodically with a continuous friction measuring device using self-wetting features. Note.— Guidance on evaluating the friction characteristics of a runway is provided in Attachment A, Section 7. Additional guidance is included in the Airport Services Manual, Part 2. [Attachment A, Section 7] 7.1 The friction of a wet paved runway should be measured to: a) verify the friction characteristics of new or resurfaced paved runways when wet (Chapter 3, 3.1.24); b) assess periodically the slipperiness of paved runways when wet (Chapter 10, 10.2.3); c) determine the effect on friction when drainage characteristics are poor (Chapter 10, 10.2.6); and determine the friction of paved runways that become slippery under unusual conditions (Chapter 2, 2.9.8). 7.4 For uniformity and to permit comparison with other runways, friction tests of existing, new or resurfaced runways should be made with a continuous friction measuring device provided with a smooth tread tire. The device should have a capability of using self-wetting features to enable measurements of the friction characteristics of the surface to be made at a water depth of at least 1 mm. November 18 ICAO Annex 14 Training Course
Chapter 10 Aerodrome Maintenance 10.2 Pavements Friction characteristics A State should define what minimum friction level it considers acceptable before a runway is classified as slippery when wet and publish this value in the State’s aeronautical information publication (AIP). When the friction of a runway is found to be below this reported value, then such information should be promulgated by NOTAM. The State should also establish a maintenance planning level, below which, appropriate corrective maintenance action should be initiated to improve the friction. Furthermore, States should establish criteria for the friction characteristics of new or resurfaced runway surfaces. 10.2 Pavements [Attachment A Section 7] 7. Determination of friction characteristics of wet paved runways . A State should define what minimum friction level it considers acceptable before a runway is classified as slippery when wet and publish this value in the State’s aeronautical information publication (AIP). When the friction of a runway is found to be below this reported value, then such information should be promulgated by NOTAM. The State should also establish a maintenance planning level, below which, appropriate corrective maintenance action should be initiated to improve the friction. However, when the friction characteristics for either the entire runway or a portion thereof are below the minimum friction level, corrective maintenance action must be taken without delay. 7.9 Furthermore, States should establish criteria for the friction characteristics of new or resurfaced runway surfaces. November 18 ICAO Annex 14 Training Course
Chapter 10 Aerodrome Maintenance 10.2 Pavements Friction characteristics Table A-1 Guidance on establishing the design objective for new runway surfaces and maintenance planning and minimum friction levels for runway surfaces in use. 10.2 Pavements [Attachment A Section 7] 7. Determination of friction characteristics of wet paved runways 7.9 Furthermore, States should establish criteria for the friction characteristics of new or resurfaced runway surfaces. Table A-1 provides guidance on establishing the design objective for new runway surfaces and maintenance planning and minimum friction levels for runway surfaces in use. November 18 ICAO Annex 14 Training Course
Chapter 10 Aerodrome Maintenance 10.2 Pavements Friction characteristics Friction measurements should be taken at intervals that will ensure identification of runways in need of maintenance or special surface treatment before the condition becomes serious. The time interval between measurements will depend on factors such as: aircraft type and frequency of usage, climatic conditions, pavement type, and pavement service and maintenance requirements. 10.2 Pavements Friction characteristics [Attachment A Section 7] 7. Determination of friction characteristics of wet paved runways Friction measurements should be taken at intervals that will ensure identification of runways in need of maintenance or special surface treatment before the condition becomes serious. The time interval between measurements will depend on factors such as: aircraft type and frequency of usage, climatic conditions, pavement type, and pavement service and maintenance requirements. November 18 ICAO Annex 14 Training Course
Chapter 10 Aerodrome Maintenance 10.2 Pavements Friction characteristics Corrective maintenance action shall be taken when the friction characteristics for either the entire runway or a portion thereof are below a minimum friction level specified by the State. [Note.— A portion of runway in the order of 100 m long may be considered significant for maintenance or reporting action.] Recommendation.— Corrective maintenance action should be considered when the friction characteristics for either the entire runway or a portion thereof are below a maintenance planning level specified by the State. 10.2 Pavements 10.2.4 Corrective maintenance action shall be taken when the friction characteristics for either the entire runway or a portion thereof are below a minimum friction level specified by the State. Note.— A portion of runway in the order of 100 m long may be considered significant for maintenance or reporting action. 10.2.5 Recommendation.— Corrective maintenance action should be considered when the friction characteristics for either the entire runway or a portion thereof are below a maintenance planning level specified by the State. November 18 ICAO Annex 14 Training Course
Chapter 10 Aerodrome Maintenance 10.3 Runway pavement overlays Introductory note.— The following specifications are intended for runway pavement overlay projects when the runway is to be returned to an operational status before overlay of the entire runway is complete thus normally necessitating a temporary ramp between the new and old runway surfaces. The longitudinal slope of the temporary ramp, measured with reference to the existing runway surface or previous overlay course, shall be: a) 0.5 to 1.0 per cent for overlays up to and including 5 cm in thickness; and b) not more than 0.5 per cent for overlays more than 5 cm in thickness. 10.3 Runway pavement overlays Note.— The following specifications are intended for runway pavement overlay projects when the runway is to be returned to an operational status before overlay of the entire runway is complete thus normally necessitating a temporary ramp between the new and old runway surfaces. Guidance on overlaying pavements and assessing their operational status is given in the Aerodrome Design Manual, Part 3. 10.3.1 The longitudinal slope of the temporary ramp, measured with reference to the existing runway surface or previous overlay course, shall be: a) 0.5 to 1.0 per cent for overlays up to and including 5 cm in thickness; and b) not more than 0.5 per cent for overlays more than 5 cm in thickness. November 18 ICAO Annex 14 Training Course
Chapter 10 Aerodrome Maintenance 10.3 Runway pavement overlays Temporary ramp between the new and old runway surfaces November 18 ICAO Annex 14 Training Course
Chapter 10 Aerodrome Maintenance 10.3 Runway pavement overlays Recommendations.— Overlaying should proceed from one end of the runway toward the other end so that based on runway utilization most aircraft operations will experience a down ramp. The entire width of the runway should be overlaid during each work session. Before a runway being overlaid is returned to a temporary operational status: a runway centre line marking [conforming to the specifications in Section 5.2.3] shall be provided. the location of any temporary threshold shall be identified by a 3.6 m wide transverse stripe. 10.3 Runway pavement overlays 10.3.2 Recommendation.— Overlaying should proceed from one end of the runway toward the other end so that based on runway utilization most aircraft operations will experience a down ramp. 10.3.3 Recommendation.— The entire width of the runway should be overlaid during each work session. 10.3.4 Before a runway being overlaid is returned to a temporary operational status, a runway centre line marking conforming to the specifications in Section 5.2.3 shall be provided. Additionally, the location of any temporary threshold shall be identified by a 3.6 m wide transverse stripe. November 18 ICAO Annex 14 Training Course
Chapter 10 Aerodrome Maintenance 10.4 Visual aids Preventive Maintenance A system of preventive maintenance of visual aids shall be employed to ensure lighting and marking system reliability. [Note.— Guidance on preventive maintenance of visual aids is given in the Airport Services Manual, Part 9.] 10.4 Visual aids Preventive Maintenance 10.4.2 A system of preventive maintenance of visual aids shall be employed to ensure lighting and marking system reliability. Note.— Guidance on preventive maintenance of visual aids is given in the Airport Services Manual, Part 9. November 18 ICAO Annex 14 Training Course
Chapter 10 Aerodrome Maintenance 10.4 Visual aids Preventive Maintenance Precision Approach Runway Category I The system of preventive maintenance employed for a precision approach runway category I shall have as its objective that, during any period of category I operations, all approach and runway lights are serviceable, and that in any event at least 85 per cent of the lights are serviceable in each of the following: a) precision approach category I lighting system; b) runway threshold lights; c) runway edge lights; and d) runway end lights. In order to provide continuity of guidance, an unserviceable light shall not be permitted adjacent to another unserviceable light unless the light spacing is significantly less than that specified. [Note.— In barrettes and crossbars, guidance is not lost by having two adjacent unserviceable lights.] 10.4 Visual aids Preventive Maintenance Precision Approach Runway Category I 10.4.10 The system of preventive maintenance employed for a precision approach runway category I shall have as its objective that, during any period of category I operations, all approach and runway lights are serviceable, and that in any event at least 85 per cent of the lights are serviceable in each of the following: a) precision approach category I lighting system; b) runway threshold lights; c) runway edge lights; and d) runway end lights. In order to provide continuity of guidance an unserviceable light shall not be permitted adjacent to another unserviceable light unless the light spacing is significantly less than that specified. Note.— In barrettes and crossbars, guidance is not lost by having two adjacent unserviceable lights. November 18 ICAO Annex 14 Training Course
End of Chapter 10 Aerodrome Maintenance November 18 ICAO Annex 14 Training Course