Aviation safety issues and actions

Requirements for visual flight rules flights in dark night conditions

Issue number: AO-2011-100-SI-01
Who it affects: All aircraft operating under the night visual flight rules
Issue owner: Civil Aviation Safety Authority
Transport function: Aviation: General aviation
Background: Investigation Report AO-2011-100
Issue release date: 03 December 2013
Current issue status: Closed – Partially addressed
Issue status justification:

The ATSB welcomes the introduction of biennial flight review to maintain a night VFR (applicable to both fixed-wing and helicopter operations), and other changes to reduce the risk of this safety issue for helicopter operations. Nevertheless, the ATSB is still concerned that there is unnecessary residual risk for other fixed-wing aerial work and private flights conducted in dark night conditions under the NVFR. At this point in time, it is clear that CAA do not intend to take any further action to address this safety issues, so the ATSB is closing the safety issue as partially addressed. 

Safety issue description

Aerial work and private flights were permitted under the visual flight rules in dark night conditions, which are effectively the same as instrument meteorological conditions, but without sufficient requirements for proficiency checks and recent experience to enable flight solely by reference to the flight instruments.

Proactive action

Action organisation: Civil Aviation Safety Authority
Date: 03 December 2013
Action status: Closed

Response to safety issue by the Civil Aviation Safety Authority

On 18 October 2013, the Civil Aviation Safety Authority (CASA) stated that as part of the new pilot licencing rules (in development prior to August 2011), Civil Aviation Safety Regulation 61.970 will require pilots to demonstrate competency during biennial night visual flight rules assessments, which become effective in December 2013. As noted in the section titled Minimum requirements for night flights, this will certainly help maintain some pilots’ ability to a higher level than previously, but it will not ensure that the pilots are able to maintain their skills at an instrument rating standard.

CASA also advised of the following actions:

  • CASA will implement a regulatory change project to study the feasibility of rule changes that provide enhanced guidance on NVFR [night VFR] flight planning and other considerations, addressing all categories of operation.
  • CASA will clarify the definition of visibility as outlined in CAR [Civil Aviation Regulation] 2 to ensure the primary coincident safety issue above is dealt with. CAR 2 defines visibility as the “ability, as determined by atmospheric conditions and expressed in units of distance, to see and identify prominent unlighted objects by day and prominent lighted objects by night”. CASA will, via regulatory change project, explore the potential to add the requirement that for night visual flight rules the determination of visibility must also include the ability to see a defined natural horizon.
  • CASA will provide additional guidance material and advisory notes in Civil Aviation Advisory Publication (CAAP) 5.13-2:
    - distinguishing the difference between NVFR / IFR and instrument conditions; and
    - emphasising the authority given by a NVFR rating.

The proposed changes project will be subject to CASA’s normal consultation requirements.

ATSB comment:

This safety issue and report of safety action by CASA in response reflects that reported in ATSB safety investigation report AO-2011-102. The ATSB welcomes the intent of this proposed action by CASA in response to this safety issue. In particular, the ATSB agrees that expanding what is meant by the term ‘visibility’ at night to include the requirement for a visual horizon will help ensure that pilots operating under the night VFR will have sufficient visual cues. However, as discussed in investigation report AO-2011-102, given the importance of the safety issue, the ATSB is concerned about the indefinite nature of the proposed evaluation and other exploratory activities proposed by CASA.

As a result of this concern, the ATSB issued safety recommendation AO-2011-102-SR-059 to CASA on 8 November 2013. Although specifically referring to investigation AO-2011-102, this safety recommendation will, when adequately addressed, also address safety issue AO‑2011‑100-SI-01 in respect of the accident involving VH-POJ, 31 km north of Horsham Airport, Victoria on 15 August 2011. The safety recommendation is therefore repeated below for ease of reference.

Additional correspondence

Response date: 07 February 2014
Response from: Civil Aviation Safety Authority
Action status: Closed
Response text:

CASA partially accepts the recommendation in as much as regulation 61.970 of the Civil Aviation Safety Regulations 1998 (CASR) requires pilots to demonstrate competency during biennial night visual flight rules assessments. The regulation was made in February 2013 and commences in September 2014.

In addition, CASA also commenced a project on 16 December 2013, OS 14/01 Night Visual Flight Rules. This will consider whether to require a discernible external horizon during flights under Night Visual Flight Rules (NVFR). CASA proposes to clarify the definition of visibility in regulation 2 of the Civil Aviation Regulations 1988 (CAR) to ensure the primary coincident safety issue above is dealt with. CAR 2 defines visibility as the "ability, as determined by atmospheric conditions and expressed in units of distance, to see and identify prominent unlighted objects by day and prominent lighted objects by night". Project OS 14/01 CASA will consider whether to seek an amendment to this definition by adding to it the requirement that for NVFR, the determination of visibility must also include the ability to see a defined natural horizon. This will in effect address the root cause of the matters outlined in the safety issue as pilots will need to have a discernible horizon throughout their flight. If a discernable horizon is not present then the flight should be conducted under the Instrument Flight Rules (IFR) and all associated regulations for IFR flight will apply.

The project will also review the current NVFR regulatory requirements and CASR definitions to ensure it limits the visual environment to that in which a defined external horizon is available for aircraft attitude control. The project will examine the night VMC requirements for both rotorcraft and aeroplanes. However the outcome of the project may limit the change to the night VMC requirements to rotorcraft only in recognition of the difference in certification requirements between the categories. The project will also amend the guidance provided in CAAP 5.13-2 to emphasise the importance of maintaining a discernible external horizon at night particularly in light of the certification basis for NVFR rotorcraft.

ATSB comment:

The ATSB recognises CASA’s ongoing efforts to address this safety issue.

Response date: 24 October 2016
Response from: Civil Aviation Safety Authority
Action status: Closed
Response text:

CASA partially accepted the recommendation and advised the ATSB in February 2014 that regulation 61.970 of the Civil Aviation Safety Regulations 1998 (CASR) requires pilots to demonstrate competency during biennial night visual flight rules assessments. The regulation was made in February 2013 and commenced in September 2014.

In addition, on 16 December 2013, CASA advised the ATSB that we had commenced project OS 14/01 Night Visual Flight Rules. This considered whether to require a discernible external horizon during flights under Night Visual Flight Rules (NVFR) and whether to amend the definition of visibility in regulation 2 of the Civil Aviation Regulations 1988 (CAR).

The project also reviewed the current NVFR regulatory requirements including CASR definitions and examined the NVMC requirements for both rotorcraft and aeroplanes. The project also proposed to amend the guidance provided in Civil Aviation Advisory Publication (CAAP) 5.13-2 to emphasise the importance of maintaining a discernible external horizon at night particularly in light of the certification basis for NVFR rotorcraft.

The outcomes of the project were limited to rotorcraft only in recognition of the difference in certification requirements between rotorcraft and aeroplanes.

As a result of this project I would like to advise that CASA has taken the following actions:

  1. CAAP 5.13-2 was withdrawn and Advisory Circular (AC) 61-05 Night VFR Rating was published in April 2016 to provide information on the certification criteria for helicopters under the NVFR and the importance of maintaining sufficient visual cues for aircraft attitude control in light of the certification requirements (at section 6.5), and
  2. On 27 April 2015, Civil Aviation Order 20.18 Amendment Instrument 2015 (No. 2) was made and commenced on 1 January 2016. The amendment instrument inserted a new paragraph 3.2A into CAO 201.18, to clarify that a helicopter may only be operated under V.F.R. at night if equipped with: the instruments specified in Appendix VIII of the CAO; and any other instruments and indicators specified in the helicopter's flight manual. It also required that if the helicopter's attitude cannot be maintained by visual external surface cues, the helicopter must be equipped in accordance with subparagraph 4.2 (d) of CAO 20.18 regarding an automatic pilot or automatic stabilisation system, or be operated by a qualified 2-pilot crew.

CASA considers this safety recommendation has been addressed and requests that this advice be published on the ATSB website.

ATSB comment date: 24 October 2016
ATSB comment:

On 24 October 2016, CASA advised the ATSB that it considers Safety recommendation AO- 2011-102-SR-059 had been fully addressed. While acknowledging the safety actions undertaken by CASA, the ATSB remains concerned about instrument proficiency, and visibility requirements for fixed-wing operations at night.

The ATSB welcomes the introduction of a biennial flight review for the night VFR rating, however does not consider that it fully supports the safety recommendation as there is no formal ongoing requirement to maintain instrument flying proficiency and currency.

CASA has addressed night visibility flight requirements for helicopter flights by amending AC 61-05 (section 6.5.5.1) and CAO 20.18 (section 3.2A (c)) however the ATSB is concerned the same standards do not apply to fixed-wing operational equipment. This relates directly to the safety issue raised as a result of another VFR flight into dark night accident investigated by the ATSB (AO-2011-100).

Based on CASA's actions to date, the ATSB intends to publish CASA's response on its website and retain the current status of safety recommendation AO-2011-102-SR-059 as 'Monitor'.

Safety recommendation

Action number: AO-2011-102-SR-059
Action organisation: Civil Aviation Safety Authority
Date: 24 October 2016
Action status: Monitor

Safety action pending and will be monitored and reported on as part of the administration of AO‑2011‑102‑SR‑059.

The Australian Transport Safety Bureau recommends that the Civil Aviation Safety Authority prioritise its efforts to address the safety risk associated with aerial work and private flights as permitted under the visual flight rules in dark night conditions, which are effectively the same as instrument meteorological conditions, but without sufficient requirements for proficiency checks and recent experience to enable flight solely by reference to the flight instruments.

Last update 07 June 2021