Mode Aviation
Reference No. AR201700028
Date reported 23 March 2017
Concern title Raised runway lights on a runway being used by gliders
Concern summary

The concern related to the use of raised runway lights on a runway which is used by gliders.

Industry / Operation affected Aviation: General aviation
Concern subject type Aviation: Airport

Reporter's concern

The reporter expressed a safety concern related to the runway markers and runway lights which are used to mark and light the [Location] runway strip and runway.

The reporter advised that [Location] is used mainly for gliding operations. The requirement in MOS139 is that frangible markers are used – but there is a difference between what is frangible to an RPT aircraft and a glider. If these were changed there would be a significant improvement in safety for glider pilots.

Several requests have been made to change the gable markers to flush markers which are allowed under MOS 139 to no avail.

Reporter’s comment: Gable markers and raised runway lights which are used to mark and light runways have resulted in substantial damage to gliders which have struck them and are a known hazard to gliders. A wingtip which has suddenly stopped can cause a glider to yaw and then ‘cartwheel’ with the nose impacting the ground vertically and the glider ending up upside-down. Flush gable markers and runway lights almost completely eliminate the risk.

Operator's response (Operator 1)

Thank you for your email containing details of the REPCON report for [Location]. In reading the documentation I understand there are two issues; one relating to raised runway lighting, and the other relating to gable markers.

I have spoken with our Council Airport Reporting Officer, reviewed correspondence from CASA, and a CASA notice (attached).

I have provided a response to both issues below.

Runway lighting

I confirm that an elevated PAL system is installed to the sealed runway, as per the requirements set out in MOS 9.1 and 9.3.

It should be noted when considering this matter that running parallel to the sealed runway, there is a glider operations strip, marked by orange gable markers, and clearly defined in the ERSA Local Traffic Regulations as being intended for Gliding Operations.

There is no lighting installed to either of the gliding operations strips at the [Location]. The risk runway lighting poses to gliders is very low as gliding operations are conducted from the designated Gliding Operations strips.

Care has been taken to ensure the ERSA for the [Location] outlines the purpose of these strips as being for Gliding Operations. Gliders should use these strips.

Gable Markers

[Location] uses orange gable markers as per MOS 8.2.2 to define the two glider operations strips. The gable markers define the strips at ground level (and from the air) and allow for clear on-ground delineation of aircraft related take-off/landing areas. The Council considers it is essential that all strips and runways are defined and visible from the ground, as well as from the air.

This is in part due to the public vehicle traffic entering the [Location] to partake in glider joy flights. The Gliding Club of [State] advise that it is not possible to escort members of the public to the glider strips for glider flights and that they must be able to drive there directly via internal perimeter roads. It is therefore essential that the two glider strips are very clearly defined on ground to minimise risk of accidental vehicle incursion.

Pilots also need to be able to see the gables from the ground during take-off operations. Flat gable markers afford very limited on ground visibility and because of this limited visibility are a very poor choice of marker.

Flat gable markers are very hard to see from the ground and pose a serious risk of accidental vehicle incursion into designated aircraft take-off/landing area. The risk posed by the permanent installation of flat gable markers is not acceptable to the Council and therefore permanent permission to have flat gables installed at [Location] has not been sought from CASA.

A special exemption was sought from CASA to use flush markers during a recent competition. This exemption was sought on the insistence of the competition director.

The application was not supported by council airport reporting officers but was facilitated due to the unique nature of the event and subject to safety arrangements being put in place to manage the risk associated with the poor visibility of flat gable markers.

The large number of gliders present during the competitions is a rare situation for [Location] and therefore the request for flat markers was sought, but only due to the unique nature of the event.

The use of flat gable markers allowed wing tips of gliders to overhang the defined grass strip and were required to grid a very large number of gliders in multiple rows before being attached to tug aircraft tow ropes.

The flush markers defining the glider strip are very hard to see from ground level, and during the competition, for this reason specific procedures were adopted to mitigate the serious risk that vehicles or persons could accidentally enter the poorly defined glider operations strip whilst flight operations were in place.

Procedures adopted to mitigate the risk included a restricted airport and a large number of identifiable ground stewards in high vis directing vehicle traffic, and also identifying and authorising persons and vehicles that may enter various areas.

Daily briefings were held to communicate safety concerns in regard to vehicles and to reinforce the Council policy that all vehicles air-side were to have an orange rotating beacon on the vehicle roof.

During normal airport operations it is not feasible to have stewards present to monitor and direct vehicle traffic.

Due to the safety risks posed by flat gable markers, that are very hard to see, the Council do not support their use at the [Location]. The risk of poorly defined glider strips is, in our assessment, greater than the risk posed by a glider striking a gable marker, which are already designed and installed to meet applicable standards.

Regulator's response (Regulator 1)

CASA has reviewed the REPCON and concurs with the points made by the [Location] Rural City Council in their response. In addition, CASA notes that:

  • If gliders are operating only from the defined glider runway strips which meet the Manual of Standards (MOS) Part 139 requirements, there is minimal risk of a glider striking an elevated light or gable marker. This is because these visual aids would be located either along the boundary of or outside the glider runway strip where gliders are not expected to operate.
  • Flush markers are less visible than elevated markers. If flush markers are used, there is an increased risk of a runway incursion by a vehicle. This risk needs to be addressed via separate mitigation measures if flush markers are used.
  • Both flush markers and elevated lights need to be frangible under the current MOS Part 139. The nature of frangibility is that no or minimal damage is sustained by the aircraft in the event of an excursion outside of the defined glider runway strip.
  • The minimum width of a glider runway strip in the current MOS Part 139 is 37.5m. An additional 3m buffer is then provided if the glider runway strip is aligned next to a runway which has a lighting system installed. If gliders are operating with a wingspan larger than what is common to most gliders (i.e. high performance gliders), the glider operator may need to reconsider operations on that glider runway strip unless a wider strip can be provided by the aerodrome operator.

The discussion raised by the glider operator about the concerns of elevated markers and lights has been subject to continuous discussions between aerodrome operators and glider operators at numerous airports. The outcome of those discussions has consistently been that it is up to the aerodrome operator to determine the best and safest use of their facility for the type of operations they intend to support or attract. The safety concern raised by the glider operator and their perceived risk is a matter for that operator to manage which may include abstaining from using the aerodrome facility until their perceived safety concerns are addressed to the point that the risk is eliminated or appropriately managed.

The matters being managed by [Location] Rural City Council extend across Workplace Health and Safety and Aviation Safety. How Council chooses to maintain and operate their property is a matter for Council. CASA works closely with [Location] Rural City Council and other authorisation holders as necessary. Raised runway lighting and runway markers are the norm for regulated aerodromes that support all types of aircraft operations. The regulatory need for Council to install and maintain the markers and lights is in accordance with the provisions of Civil Aviation Safety Regulations (CASR) 1998 Part 139 and the MOS Part 139 Aerodromes. In accordance with CASR 1998 Part 11, CASA may provide an instrument to the authorisation holder (e.g., Council) subject to a safety case upon submission from the authorisation holder to vary the requirements of the regulations or standards. However, such an instrument has not been sought.

Members of various organisations, including the reporter/gliding representative, may submit a request to Council for consideration of their activities and needs. Council considers applications on merit. If Council choose to refuse the request it would not be appropriate for CASA to intervene as the aerodrome meets its regulatory requirements. The reporter has not appeared to have considered that the gliding operations as outlined are posing a risk to council facilities and infrastructure and other aerodrome users, including the glider operator themselves and their passengers.

The Part 139 Regulations and Standards are being reviewed at the moment and there is representation from The Gliding Federation of Australia (GFA) on that working group. The outcomes of the review may enable Council to review the standards applicable to their aerodrome facility. However, the review will not result in a direction to Council to amend their facility unless they otherwise determine to do so.

The reporter is urged to continue to work with Council to achieve a satisfactory outcome and to assess the risk they pose to council facilities and the aerodrome's infrastructure. The reporter should consider the hazards they perceive and take appropriate risk mitigation to ensure continued safety of both their own operation and the operation of others.

Proposed Part 139 Post Implementation Review (PIR) actions:

These types of issues have been raised by the GFA and feature in the MOS Part 139 issues register as an element of the Part 139 PIR.

The latest draft MOS Part 139 proposes:

  • To make the provision of flush markers more flexible. If flush markers are used, however, the draft MOS proposes that the flush markers be maintained free of contamination and that the vehicle incursion risk is subject to additional mitigation;
  • No change to existing lighting standards with regard to light fitting location, frangibility and height; and
  • No change to the width and location of existing glider runway strips.

The proposals in the draft MOS Part 139 will be released by mid-year 2017 as part of the Notice of Proposed Rule Making (NPRM). [Location] Rural City Council, the Gliding Federation of Australia and the REPCON reporter will be free to provide comment on the proposed changes.

Last update 12 July 2018