Synopsis

EUROCONTROL has been notified of incidents of aircraft crossing runway-holding positions and associated stop bars, which had been switched off, and then entering the runway without a valid ATC clearance. In some instances pilots report of inconsistent local policies on the use of stop bars (e.g. low visibility ops only, H24 operation on some runways, at some airports, in some States), which, in their opinion, contributed to confusion or to an assumed ATC clearance to proceed.

ICAO PROVISIONS

• ICAO Annex 2, Rules of the Air,
  • 3.2.2.7.2: “An aircraft taxiing on the manoeuvring area shall stop and hold at all runway-holding positions unless otherwise authorized by the aerodrome control tower.”
  • 3.2.2.7.3: “An aircraft taxiing on the manoeuvring area shall stop and hold at all lighted stop bars and may proceed further when the lights are switched off.”
• ICAO Annex 14, Aerodromes:
  • 5.3.19.3 (Note 1): “A stop bar is switched on to indicate that traffic stop and switched off to indicate that traffic proceed.”
• ICAO Doc 4444, PANS ATM:
  • Definitions - Runway-holding position: “A designated position intended to protect a runway, an obstacle limitation surface, or an ILS/MLS critical/sensitive area at which taxiing aircraft and vehicles shall stop and hold, unless otherwise authorised by the aerodrome control tower.”
  • 7.15.6 Taxiway lighting: “Note: Taxiway lighting includes such lights as edge lights, centre line lights, stop bars and clearance bars. Where required to provide taxi guidance, taxiway lighting shall be turned on in such order that a continuous indication of the taxi path is presented to taxiing aircraft. Taxiway lighting or any portion thereof may be turned off when no longer needed.”
  • 7.15.7 Stop bars: “Stop bars shall be switched on to indicate that all traffic shall stop and switched off to indicate that traffic may proceed.”
• ICAO Doc 9870, Manual on the Prevention of Runway Incursions
  • Rec 4.3.2 (Aircraft Operators): “A requirement to obtain an explicit clearance to cross any runway should be included in the flight deck procedures. This includes runways not in use.”
  • Rec 4.5.6 (ANSP): “It should be ensured that ATC procedures contain a requirement to issue an explicit clearance including the runway designator when authorising a runway crossing or to hold short of any runway. This includes runways not in use.”
  • (Best Practice for Taxi) 6.3.7: “When a clearance to taxi to a point beyond a runway is received, it must include the authorization to cross that runway. A runway should never be crossed unless an explicit ATC clearance has been received.”

ANALYSIS

It is important that the ICAO provisions related to runway-holding positions, the operation of stop bars and associated ATC clearance are read and understood in conjunction with one another and in the appropriate context. If they are not there is a risk that as they are currently written Annex 2, 3.2.2.7.3, Annex 14 5.3.19.13 (Note 1) and PANS ATM 7.15.7 could be misconstrued as authority for pilots to proceed beyond the holding position/stop bar without an ATC clearance. This is not the case. ICAO Annex 2, 3.2.2.7.3 must be understood in the context of the preceding 3.2.2.7.2 which clearly explains that pilots can proceed beyond the holding position only when “…authorised by the aerodrome control tower”, i.e. an ATC clearance has been issued.

Moreover, Annex 14 5.3.19.13 (Note1) and PANS ATM 7.15.6 and 7.15.7 are concerned only with the physical operation of the stop bars by ATC controllers, and should not be understood as authority for pilots to proceed beyond the holding position/stop bars without an ATC clearance. The observation that a previously lit stop bar has been turned off, or that a stop bar is not lit, should be interpreted only as a visual confirmation of an ATC clearance to proceed.

To make this absolutely clear, in October 2010 the ICAO Aerodrome Panel proposed a revision to Annex 14, 5.3.19.13 (Note) to the effect that the phrase “in conjunction with an explicit ATC clearance” be added at the end. This proposal was subsequently endorsed by the ICAO Air Navigation Commission and will be subject to ICAO State Letter consultation. The ICAO Secretariat is also considering similar proposals for the other provisions quoted.

The European Action Plan for the Prevention of Runway Incursions (EAPPRI) Version 2, release planned for 2011, contains a new Recommendation 1.7.6 concerning the operation of stop bars on aerodromes: “Ensure that Aerodrome Operators and Air Navigation Service Providers regularly review the operational use of aeronautical ground lighting e.g. stop bars, to ensure a robust policy to protect the runway from the incorrect presence of traffic.”

SAFETY REMINDERS

Runway-holding position markings are the primary means used to protect the integrity of the runway. Where switchable stop bars are provided, either at a runway or elsewhere in the taxiway system, they are there to support and reinforce designated positions and are not a replacement for them.

• Notwithstanding this general statement, stop bars are an important safety net at some aerodromes and ICAO Doc 9870 also provides other recommendations and best practices for both pilots and ATC controllers, namely:
  • Rec 4.4 (Pilots): “Pilots should never cross illuminated stop bars when lining up on, or crossing, a runway…”
  • Appendix B - Best Practice for Flight Deck: “Red stop bars should never be crossed when lining up on or crossing a runway unless, in exceptional circumstances, the stop bars, lights or controls are reported to be unserviceable, and contingency measures, such as using follow-me vehicles, are in force...”
  • Rec 4.5.5 (ATCOs): “Aircraft or vehicles should never be instructed to cross illuminated red stop bars when entering or crossing a runway.”
• Therefore, it follows that before crossing stop bars pilots should:
  1. challenge ATC if they are cleared to cross an illuminated stop bar - RED means STOP;
  2. confirm that the stop bars are switched OFF (except in the exceptional circumstances described in ICAO Doc 9870, Appendix B above); and
  3. have an ATC clearance to proceed beyond any holding position/stop bar, in particular those protecting runways.
• State authorities, aerodrome operators and ANSPs should ensure the consistent operation of stop bars that protect the runway(s) e.g. low visibility ops only, H24 operation.

YOUR ATTENTION IS REQUIRED

• Air navigation service providers and aircraft and aerodrome operators are invited to review the use of stop bars that protect the runway and investigate the relevance for their runway operations.
• State aviation authorities are invited to review their national rules’ compliance with ICAO provisions.

FURTHER READING

• ICAO Doc 9870, Manual on the Prevention of Runway Incursions.
• EUROCONTROL Runway Safety
  • European Action Plan for the Prevention of Runway Incursions (EAPPRI) - 2017
  • Use of Stop Bars H24 Study Report
• SKYbrary:
  • IFATCA Stop Bar Survey Report - December 2008
  • Runway Holding Point Lighting

Disclaimer

© European Organisation for Safety of Air Navigation (EUROCONTROL) February 2011. This alert is published by EUROCONTROL for information purposes. It may be copied in whole or in part, provided that EUROCONTROL is mentioned as the source and to the extent justified by the non-commercial use (not for sale). The information in this document may not be modified without prior written permission from EUROCONTROL. The use of the document is at the user’s sole risk and responsibility. EUROCONTROL expressly disclaim any and all warranties with respect to any content within the alert, express or implied.