Mode Aviation
Reference No. AR201700050
Date reported 13 May 2017
Concern title Pilot activated lighting system at [Location]
Concern summary

The concern related to the lack of pilot feedback for activation of the pilot activated lights at [Location].

Industry / Operation affected Aviation: Airports
Concern subject type Aviation: Airport

Reporter's concern

he reporter advised that [Location] has a pilot activated lighting (PAL) system. The activation of this system is often ineffective, but as there is no PAL AFRU there is no feedback to the pilot that the lighting has not activated. Several pilots have reported that they have trouble activating the lights.

Pilots using the system are concerned that when they are flying at night in IMC and conducting an instrument approach, they have no confirmation that the lights have activated.

Reporter’s comment: We see this as a major safety issue with the [Location] Airport and would like a review of the system with the aim to have a PAL-AFRU system installed.

Named Party’s response:

Thank you for providing the opportunity to comment on the safety concern, relating to the lighting system at [Location] Airport.

[Location] Airport Operations Management has received no formal advice or complaints relating to an "ineffective" lighting system.

There has been no report or contact with the airport on call duty airport reporting officer (ARO) regarding pilot activated airport lighting control (PAALC) activation issues.

The PAALC unit at [Location] Airport is a Version 2, manufactured by the Department of Transport SA/NT. The AFRU is a MicroAir Electronics 760. These units are of an older design, the two are not linked.

We accept the PAALC used at [Location] Airport is that of an older standard, however, other than [operator], the amount of night operations into [Location] Airport, is negligible. We believe with the amount of night flights into our airport, the current PAALC meets the industry needs and is compliant with CASR MOS 139, Ch9- old style PAALC.

The statement "the activation of this system is often ineffective" is open ended, we invite the author of the safety concern, to provide us with details of how the PAALC, in their opinion is ‘ineffective’.

[Location] Airport does not accept that the current PAALC is ineffective, simply because it is not the authors preferred design.

The continual reference to the term, PAL AFRU, suggests to us that pilots of the organisation conducting night operations into our airport, are unfamiliar with the PAALC equipment in use at [Location] Airport.

There is a different method of activating the older style PAALC compared to the new style PAL AFRU. If the pilots are using the same activation sequence of the PAL AFRU system to activate the PAALC, obviously the lighting will appear to be ineffective.

Not all airports have AFRU/PAL equipment.

The ERSA for [Location] shows Aerodrome and Approach Lighting activation is via frequency [frequency]. We are aware of pilots attempting to activate the lighting by using the CTAF frequency of [frequency].

We accept there may be some confusion with the wording of the ERSA, which references activation of lighting via PAL [frequency], perhaps pilots believe this refers the PAL AFRU. The wording will be changed in the next publication of the ERSA, alleviating any confusion.

The below extract is from CASRS MOS 139 CH 9

Old style PAALC

Pilots are advised that the code they should send is three bursts of approximately 3 seconds, with at least 1 second between bursts, and the three bursts must be transmitted within 25 seconds.

And new style AFRU/PAL

14 .3.6.2

The Pilot Activated Lighting (PAL) option includes a light sensor mounted remotely from the AFRU. During the time the light sensor detects that the natural light intensity is less than a pre-set level (adjustable on the AFRU unit), and on receipt of an aircraft transmission of three carrier bursts (three push-to-talk (PTT) clicks) over a five-second period, the AFRU will provide separate relay outputs to operate the airport lighting circuitry (runway lights and illumination of the wind indicator) at the aerodrome. The AFRU will then transmit the standard reply of the normal pre-recorded voice message (the aerodrome name and MBZ or CTF), followed by the additional recorded voice message of ‘runway lights on’. The runway lights will operate for a period of either 30 minutes or 60 minutes. The operating period of either 30 minutes or 60 minutes will be pre-set within the unit. Ten (10) minutes prior to the end of the 30 or 60 minute period, the windsock light will flash a 1 second intervals and the MBZ/CTAF response, followed by the announcement ‘runway lights 10 minutes remaining’ will be broadcast. At any time during the period of time that the lights are operated, receipt of a further transmission of three carrier bursts shall reset the timing period back to either 30 or 60 minutes.

We further wish to advise, an airport lighting serviceability inspection is carried out by the Duty ARO daily, after the departure of the last RPT flight. Additionally, weekly day stage lighting inspections and night stage lighting inspections are performed as per the requirements of MOS 139.

Owing to the remoteness, and as part of the [Location] Airport commitment to aviation compliance and safety, our Airport Aviation Electrical Specialist visits the airport at approximately 6 monthly intervals (spending 6 to 8 days) to carry out preventative maintenance to the electrical and lighting systems.

We believe our airport to be well maintained in all aviation areas. We welcome feedback from airport operators, we believe the difficulties being experienced by this particular operator, could be overcome with better understanding of the current PAALC equipment in use at this airport.

Regulator's response (Regulator 1)

CASA has reviewed the REPCON and notes that [Location] Airport is equipped with a Pilot Activated Lighting (PAL) system and a separate Aerodrome Frequency Response Unit (AFRU).

The operation of the PAL and AFRU is subject to routine inspections by the aerodrome operator with no significant concerns identified. Where an outage is identified, a NOTAM is published advising of any outage. Runway lights are left energised if an outage is identified.

[Location] Airport publishes a CTAF-AFRU on [frequency 1] in the Aeronautical Information Publication – En Route Supplement Australia (AIP-ERSA) (25 May 2017). The system is not a PAL-AFRU.

[Location] Airport provides a certified air/ground radio service (CA/GRS) during scheduled Regular Public Transport (RPT) hours of operation. When the CA/GRS is out of hours the aerodrome is supported by an Aerodrome Frequency Response Unit (AFRU). The runway lights are activated on PAL frequency [frequency 2].

The activation sequence of a PAL and a PAL-AFRU are different. The following is an excerpt from the AIP-ERSA:

23.3 Operation of VHF Pilot Activated Lighting (PAL)

  1. ON DEPARTURE: Before taxi
  2. ON ARRIVAL: Within 15 NM of AD, and at or ABV LSALT select the appropriate VHF FREQ:

_____3 SEC_____ _____3 SEC_____ _____3 SEC_____


(i) Transmit pulse must be between 1 and 5 SECS

(ii) Three pulses must be transmitted within 25 SECS. Ensure that the third pulse ends before the 25th second.

(iii) Break between transmissions can be more or less than 1 SEC - (no limit)

Lights to illuminate for a minimum of 30 MINS. If not:

- keep transmitting 3 SEC pulses

- check frequency

(iv) When runway lights are about to extinguish, the wind indicator light will flash continuously.


23.4 Aerodrome Frequency Response Unit With PAL Option (AFRU + PAL)

  1. On receipt of the required ACFT transmission the AFRU will operate the aerodrome lighting circuitry (RWY and wind indicator lights). The AFRU will transmit the standard reply (the aerodrome name and CTAF) immediately followed by the additional confirming message, “RUNWAY LIGHTS ON”. If the lights do not illuminate, the AFRU will transmit the message, “NO RUNWAY LIGHTS”. In this case, pilots should key the required transmission again or, alternatively, change to the PAL FREQ and operate the lights via the PAL.
  2. AFRU + PAL required transmission is:



Note: Transmission to be completed in 5 seconds. If unsuccessful repeat transmission.

  1. After actuation, the aerodrome lights will remain illuminated for 30 minutes. After 20 minutes, the windsock lights will flash at 1 second intervals and the AFRU will transmit the message, “RUNWAY LIGHTS 10 MINUTES REMAINING”. At any time, keying of the required transmission will reset the lights for a period of 30 minutes.
  2. Aerodromes which have the AFRU + PAL option will have the entry “PAL + AFRU” included under the “LIGHTING” heading.

The system is checked daily as part of routine serviceability requirements with no specific serviceability concerns identified as part of that inspection process.

As identified by [Location] Airport the current systems are operating efficiently and the cost of providing updated infrastructure is not warranted by the amount of traffic when the existing infrastructure is fit for task. The replacement of the existing systems will be subject [airport operator] and their stakeholder engagement process at that time.

Last update 18 July 2018