The occurrence flight used a distance measuring equipment (DME) arrival to establish a visual approach in unsuitable visibility conditions. The investigation identified a number of similar approaches conducted by the operator in marginal visibility conditions. Using this approach method, rather than a straight in instrument approach, significantly reduced obstacle clearance assurance for both an approach and any potential missed approaches, and also increased the risk to both the operator’s and other aircraft through the use of a non-standard circuit procedure.
The ATSB is satisfied that the changes to the Eastern Air Link exposition provides appropriate guidance to flight crews on the safest option in the selection of an approach procedure when weather conditions are marginal for the conduct of a visual approach.
The ATSB recommends that Eastern Air Link addresses the safety issue, through provision of guidance and training to flight crew concerning the safest option in the selection of an approach method when weather conditions are marginal for the conduct of a visual approach.
The ATSB was advised that, following the recent appointments of new Head of Flight Operations and Head of Training and Checking, Eastern Air Link (EAL) revisited the occurrence involving VH-MVP in February 2022. To avoid potential misinterpretation of the previous text, that review resulted in further amendments to 2 sections of the exposition. The amended sections, and changes, were as follows:
On review of the changes to the EAL exposition, and the application of those changes, the ATSB is satisfied that the safety action taken by EAL provides appropriate guidance to flight crews on the safest option in selection of an approach procedure when weather conditions are marginal for the conduct of a visual approach.
On 14 February 2023, following ATSB’s briefing on the safety issue titled 'Inappropriate use of the visual approach in marginal weather' and request for advice on safety action to address the issue, Eastern Air Link advised the ATSB that notification of these events to the Civil Aviation Safety Authority (CASA) resulted in CASA initiating surveillance activity. As a result of that activity, the Operations Manual Volume 2 -- Aircraft Operations was amended, with CASA acceptance. The relevant amendments within this manual were as follows:
In response to a request from the ATSB for further detail on the reason for these changes, Eastern Air Link provided the following additional information:
The current text to Vol 3 [which provided specific guidance on meteorological threats specific to Lord Howe Island] but text in Vol 2 [the operations manual] required amendment as it appeared to offer a disconnect with Vol 3. Amended text to Vol 2 was subsequently offered and approved by CASA (3/8/22) …
The changes did not call for any specific training, per se. What was required was information to alert Flight Crew to the nuances of the changes, namely – (a) the precautionary statements with regard to self-briefing when meteorological conditions or terrain demanded, shall we say, “a little more attention” and this would be highlighted in Vol 3 and (b) the requirement with regard to manoeuvring within the 3 NM of the runway. Neither is trainable but what was put into effect was:
1. [through] a check of the sign on process the Chief Pilot confirmed that the Flight Crew were aware of the amendment and the requirements to each issue, and
2. thereafter, this will be confirmed via the Flight Crew’s subsequent route check…
Regarding methods and systems employed to ensure that these changes are being applied in practice, and to ensure effective implementation, it is a requirement of our Training and Checking System that the Flight Crew are checked annually on the route. Therefore, as well as being made aware of changes through the Ops Manual amendment process, the Chief Pilot, who conducts this check, will confirm compliance with this as well as all relevant aspects of the Operations Manual generally.
Regarding what training systems and notification methods were used to ensure that flight crew were conversant with these changes to the operations manual, when any amendment is made to the Operations Manual, Flight Crew are advised by Flight Standing Order.
In response to the request for advice on actions specific to the safety issue, Eastern Air Link provided the following statement:
General Comment
Lord Howe Island (LHI) should never be considered your average Australian airport and should always be treated with great respect. Eastern Air Link (EAL) has quite an extensive Pilot in Command initial route training program supported by an annual route qualification regime. Moreover, and for good reason, the LHI section of Volume 3 of the EAL Operations Manual (Aerodromes and Routes) is by far the most extensive. The information in that manual is there to inform and remind Flight Crew that LHI’s remote location, together with its topography, oceanic weather environment and significant seasonal bird life creates, and will continue to create, a challenge for Flight Crew who regularly operate there.
Naturally, the Australian Aviation Regulations apply at LHI but strict application of the standard, rectangular circuit pattern without considering the actual LHI conditions, may well place the aircraft in an unsafe position. Sound, safe airmanship is always required.
Visual Approach in Marginal conditions
At the heart of this issue is a safe assessment of what constitutes Visual Meteorological Conditions (VMC). This assessment is the responsibility and the prerogative of the Pilot in Command (PIC). If safely and correctly assessed, a visual approach, even in marginal conditions, remains a viable and safe option.
With refence to ATSB’s concerns, the discontinuance of an IFR approach in marginal conditions, the PIC to must ensure that VMC exists and will continue to exist during the approach - otherwise the published Missed Approach must be conducted. However, in marginal weather conditions it is not uncommon for there to be ‘holes’ or ‘areas of VMC’ that enable a safe approach to be conducted even when the rest of the sky would be deemed to be non VMC. In this scenario, a visual approach in marginal conditions remains a safe option. EAL expects its Flight Crew to be wise with their assessments and, if any doubt exists, to always take the safer option. This is stressed in their training and is regularly assessed.
The safety issue does not question the conduct of a visual approach in appropriate weather conditions. However, the safe conduct of a visual approach in marginal conditions relies on the pilot's subjective assessment and introduces the possibility of encountering either improved or deteriorating conditions, particularly in the significantly dynamic meteorological environment that Lord Howe Island often presents.
In the case of the occurrence approach, a visual approach conducted in marginal weather conditions introduced an unnecessary risk of loss of visual reference in relatively close proximity to terrain, which was further exacerbated as the ‘visual only missed approach’ could not be performed safely due to loss of adequate visual reference and reduced obstacle clearance assurance. The advantages to conducting a visual approach in marginal condition are outweighed by the significant increase in safety risk. Further, the concept of utilising 'VMC holes' further increases risk, through the reliance on local improvements in weather conditions that may quickly deteriorate, as was the case in this occurrence.
The ATSB remains concerned that the operator’s conduct of visual approaches in marginal weather conditions presents an unacceptable and ongoing risk of a similar occurrence, with possibly more severe consequences. As such, the ATSB makes the following safety recommendation.
The ATSB acknowledges Eastern Air Link’s changes to the 3 NM limit for manoeuvring for a straight-in approach, but notes these were actioned through notice only with no supported training. Consequently, the ATSB examined flight crew actions during approaches into Lord Howe Island during a period of potential marginal weather conditions on 3 February 2023. While the weather conditions at that time did not qualify as being marginal for a visual approach, the data was mixed, with 2 of the 4 arrivals positioning for a straight-in approach while within the 3 NM manoeuvring limit. This prompted a request for further clarity on how the proposed changes were being implemented as the non adherence to the operational change indicates that, without any attached guidance or training component to emphasise and support the change, its implementation had been ineffective.
The changes to the stabilised approach criteria, and the later advice on the intention of this change, also required closer examination. In guidance on the appropriate response to deviation from stabilised approach criteria, the Flight Safety Foundation recommends that:
If the approach is not stabilized before reaching the minimum stabilization height, or if any flight parameter exceeds deviation limits (other than transiently) when below the minimum stabilization height, a go-around must be conducted immediately.
Transient deviations from stabilised approach criteria are generally accepted when turbulent conditions exist, whether the result of weather or the effects of local terrain, although should conditions result in serious deviation, the safest option is to go around. A transient deviation acceptance could be read into the content of 2C6.6.2, with the statement that ‘only minor corrections to speed and flight path, to maintain a stable approach, should be required…’ however, both this text, and the new note raised the question of what is required where more serious deviation results. The note gives no indication of transient exceedances being the issue but permits intentional exceedance of stabilised approach criteria should conditions necessitate, if that exceedance was foreseen through a special briefing. However, the ATSB notes that:
The stabilised approach method, and the well-established limits therein, has resulted in a significant reduction in loss of control and collision with terrain accidents during approach and landing. This method and the associated limits are recognised and followed globally and operate successfully in environments that present the possibility of conditions more extreme than that presented by Lord Howe Island, and without the need for acceptance of deviation. Further, this modification to the note following the stabilised approach criteria has the potential to validate the manoeuvring conducted during the occurrence event, as well as introducing the potential to significantly increase risk where meteorological conditions exist to justify extreme breaches of stabilised approach criteria.
In summary, the ATSB considered that Eastern Air Link’s initial response and the associated safety action did not address the safety issue. Therefore additional information was sought from the operator.
