Recommendation R19980057

Recommendation issued to: Civil Aviation Safety Authority

Recommendation details
Output No: R19980057
Date issued: 26 May 1998
Safety action status:


While taxiing on a non-active runway at Moorabbin, the pilot of the aircraft crossed the duty runway without a clearance. The pilot later reported that he had become confused, and considered that the markings to indicate the approach to the active runway were inadequate.


Moorabbin has no runway markings in the form of "taxiway hold point lines", or signs to indicate to a pilot that his aircraft is about to infringe the flight strip of an active (duty) runway.


Moorabbin airport operations

The investigation of this occurrence revealed that when aircraft are being taxied on non-active runways, there are no signs or runway markings to indicate to pilots that the aircraft is about to infringe the flight strip of the duty runway. For example, when pilots are taxiing on runway 22/04 and approaching 13R/31L or 17L/35R, they must rely on being able to view the gable markers of the active runway's flight strip in order to make an assessment of when to stop and seek a clearance to cross the active runway. On some occasions, pilots may not easily acquire the visual cues provided by gable markers due to their distance/spacing from the runway and other factors such as the nature of the runway strip surface. On these occasions, pilots must make a subjective judgement. Without cues such as guidance signs or runway markings, it is more likely that pilots will misjudge their position in relation to the flight strip, or that thay will continue onto the active runway without a clearance, having given little or no conscious thought to the need to stop. Such information signs are in use at Melbourne aerodrome.

A Moorabbin tower controller confirmed that it is common practice to use non-active runways as taxiways in order to make best use of aerodrome resources and, in turn, maintain an efficient flow of traffic. The Bureau was informed that Melbourne aerodrome also uses runways as taxiways in times of low traffic density. As this practice appears to be a commonly accepted and utilised one, the requirement for appropriate information signs on runway-to-runway intersections may need to be addressed.

Reference material pertaining to runway and taxiway signs and markings

(1) The Rules and Practices for Aerodromes handbook

The Rules and Practices for Aerodromes handbook, issued by the Civil Aviation Safety Authority (CASA) for use by operators of licensed aerodromes, contains a number of references relating to taxiway signs. The emphasis, however, appears to be on taxiway markings/signs. Limited guidance is provided on runway-to-runway intersection markings/signs.

Chapter 11 Visual Aids - Day, paragragh 2.1, states that "visual aids are cues for pilots, marshallers, air traffic controllers and ground vehicle drivers to help them in ensuring safe aircraft operations. Visual aids assist pilots to locate an aerodrome, determine the areas of an aerodrome upon which it is safe and permissible to land and take off, taxi aircraft safely on the movement area, and precisely position aircraft on the apron".

Paragraph 8.4 states that "taxi holding position markings are used to indicate to pilots positions along taxiways at which they must temporarily hold their aircraft when a runway ahead is occupied by another aircraft, or when so instructed by ATC. They are to be provided on all asphalt, sealed or concrete taxiways wherever these join or intersect with a runway". However, there is no reference to runway-to-runway intersection markings.

Chapter 12 Movement Area Guidance Signs (MAGS), paragraph 12.5, states that "MAGS with information are normally provided where the aerodrome has multiple runways and a complex taxiway system. It is an inexpensive way to maintain the movement rate of aircraft on the taxiway, particularly in reduced visibility conditions". Again, there is no reference that specifically covers runway-to- runway intersections.

Paragragh 12.21 states that "intersection signs are information signs, which provide advice to pilots on the designation of the runway or taxiway about to be joined or crossed. When used, one intersection sign is to be provided for each direction, at the left-hand side of the taxiway as viewed by the pilot, prior to the relevant taxiway intersection. The inscription on the sign is to be the designation of the taxiway(s) being approached, as shown in Fig 11.62". This again appears to emphasise the taxiway-to-runway intersections, not runway-to-runway intersections.

(2) Aeronautical Information Publication (AIP)

The AIP defines a taxi holding point as "a designated position on a taxiway, runway or channel at which aircraft may be required to stop pending receipt of permission to proceed". The inference from this reference is that holding points may be designated for runways.

(3) The International Civil Aviation Organisation (ICAO) Annex 14-Aerodromes

This publication contains specific references to runway-to-runway intersections and indicates the requirements that must be met in relation to runway markings/signs.

Paragraph 5.4.2 - Mandatory instruction signs "A mandatory instruction sign shall be provided to identify a location beyond which an aircraft taxiing or vehicle shall not proceed unless authorised by the aerodrome control tower". "Mandatory instruction signs shall include runway designation signs, category I, II or III holding position signs, taxi holding position signs, road holding position signs and no entry signs". "A pattern "A" taxi-holding position marking shall be supplemented at a taxiway/runway intersection or a runway/runway intersection with a runway designation sign". A taxi-holding marking on a runway is a further defence to the runway designation sign.

Paragraph "The taxiway holding position marking displayed at a runway/runway intersection shall be perpendicular to the centreline of the runway forming part of the standard taxi-route".


There appears to be an accepted practice of using runways as taxiways for the management of aircraft traffic at aerodromes with multiple runways and complex taxiway systems, such as Moorabbin. Guidance available to aerodrome operators for the use of runway markings and/or signs for runway-to-runway intersections, is limited and does not appear to be adequately addressed. Consequently, there is a need to consider the requirement for a specific and unambiguous system of markings and/or signs in order to prevent the possibility of collisions, particularly at runway-to-runway intersections.

Output text

The Bureau of Air Safety Investigation recommends that the Civil Aviation Safety Authority review the adequacy of movement area guidance signs and markings, particularly at runway-to-runway intersections. The review should focus initially on Moorabbin Aerodrome and other aerodromes with multiple runways and complex taxiway systems.

Initial response
Date issued: 04 December 1998
Response from: Civil Aviation Safety Authority
Action status: Monitor
Response text:

"I refer to your letter of 25 May 1998 and the recommendation that CASA review the adequacy of movement area guidance signs and markings particularly at runway-to-runway intersections, with the initial focus an Moorabbin Aerodrome and other aerodromes with multiple runways and complex taxiway systems. The recommendation is accepted.

However, it should be noted that although CASA sets the standards on how to mark and sign taxiways and runways, the provision of such signs and markings depends on local air traffic control requirements.

In the case of Moorabbin, I understand that Mr [name supplied], our Melbourne District Aerodrome Inspector has been in contact with Moorabbin ATC on this matter. Also, arrangement will be made for the ATC, Moorabbin aerodrome operator and CASA Flying Operations Inspector to get together to developed a plan to implement appropriate information MAGS at Moorabbin Aerodrome.

I will be asking other District Offices to initiate similar action at aerodromes where there are intersecting runways and complex taxiway systems.

Further correspondence
Date issued: 07 June 1999
Response from: Civil Aviation Safety Authority
Response status: Closed - Accepted
Response text:

I refer to our 2 June 1999 telephone conversation about the progress on provision of RWY to RWY intersection hold position markings at Moorabbin Aerodrome.

A meeting was held on 23 February 1999, and attended by:

[name supplied], General Manager, Moorabbin Airports Corporation., [name supplied], Operations Manager, Moorabbin Airports Corporation; [name supplied], Airservices Moorabbin Tower Controller; [name supplied], Airservices Canberra; [name supplied], DFOM, CASA Moorabbin Office; and [name supplied], DAI, CASA Melbourne Office.

It was resolved by Messrs: [name supplied], [name supplied] and [name supplied], that RWY to RWY intersection hold position markings were necessary at the following locations:

RWY 22 east side of RWY 13R/3 IL; RWY 22 east side of RWY 17R/35L; and RWY 13 R/3 1 L east side of RWY 17R/3 5L.

The RWY to RWY intersection hold position markings are installed at the above locations.

Last update 01 April 2011