VFR into IMC involving a Piper PA-28, VH-FPS, near Warrnambool, Victoria, on 25 February 2021

Decisions regarding whether to conduct an investigation, and the scope of an investigation, are based on many factors, including the level of safety benefit likely to be obtained from an investigation. For this occurrence, a limited-scope investigation was conducted in order to produce a short investigation report, and allow for greater industry awareness of findings that affect safety and potential learning opportunities.

The occurrence

On the morning of 25 February 2021 the flight crew of a Piper Aircraft PA-28-161 aircraft, registered VH-FPS (FPS) and operated by Moorabbin Aviation Services, arrived at Moorabbin Airport to prepare for a VFR training flight.^[1] The flight crew consisted of an instructor and student pilot (student), with a second student pilot observing the flight. The flight was part of the navigation training for the student’s integrated commercial pilot licence training course.

The student obtained the weather forecast and completed the planning for the training flight, which was to depart Moorabbin Airport and overfly Bacchus Marsh, Ballarat, Ararat, Horsham, and then to Warrnambool, where they ^[2] planned to land before 1400. At Warrnambool, they planned to refuel, before returning to Moorabbin Airport (Figure 1).

Once the planning was complete, the student briefed the instructor on the forecast weather and the procedures for the flight. They identified that at the time of their arrival at Warrnambool, the aerodrome forecast (TAF) was forecasting the visibility to be greater than 10 km with scattered^[3] cloud at 3,000 ft above ground level (AGL). However, at 1500 a forecast INTER^[4] was due to commence, with the visibility decreasing to 5,000 m in showers of rain and the cloud cover increasing to broken^[5] and the cloud base lowering to 1,000 ft AGL. The student pilot did not brief the instructor on deteriorating weather in the Warrnambool area which was forecast on the graphical area forecast (see the section titled Weather forecasts) and the instructor did not detect this omission. The instructor later advised that they did not put enough emphasis on considering the weather forecast during this briefing.

Figure 1: Flight planned track and diversion

The red full line shows the flight track, which was planned and flown, the red broken line shows the intended flight planned track and the blue line shows the track flown after the diversion from Lake Goldsmith, near Ballarat, to Warrnambool.

Source: Google earth, annotated by the ATSB

The flight departed Moorabbin Airport at around 1200 Eastern Daylight-saving Time,^[6] an hour later than planned, with the student flying the aircraft from the left seat. After passing Ballarat at 4,500 ft above mean sea level (AMSL), the instructor put the student under the hood,^[7] to practise flying with reference to instruments only. After flying for about 14 minutes, the hood was removed and the instructor asked the student to identify the location of the aircraft. The student correctly identified the aircraft’s position and the instructor then tasked them to divert directly to Warrnambool, which they did successfully.

The instructor advised that the aircraft landed at Warrnambool at around 1400. The weather was clear however, as they parked the aircraft, the wind strength increased. As an air ambulance helicopter was due to land and refuel, the student and passenger took a short break in the terminal. While the helicopter was refuelling, the cloud cover increased and it began to rain. The flight crew waited until the rain stopped before commencing refuelling their aircraft.

The instructor advised that while waiting for the weather to improve, they checked the weather from various sources using their mobile phone. They observed that the TAF for Warrnambool had been amended and was now forecasting a TEMPO^[8] with the visibility reducing to 4,000 m in showers of rain and the cloud had increased to broken with the base at 800 ft AGL. They could not recall how much of the graphical area forecast (GAF)^[9] was reviewed and whether they checked the TAF for Moorabbin Airport at this time.

The instructor then contacted two senior pilots at their Moorabbin base and advised them that they were delayed at Warrnambool as the weather had deteriorated. Both of these pilots advised the instructor to wait until the weather had cleared and the senior base pilot advised them to remain at Warrnambool overnight if required.

The instructor reported that the cloud level subsequently lifted and the aerodrome weather information service (see the section titled Warrnambool airport observations) stated that the cloud was scattered at 1,900 ft AGL. A decision was made to depart, with the plan that they would return to Warrnambool if the weather deteriorated. The instructor advised that at the time of departure, while there were some clouds, there were also patches of blue sky and the visibility to the east was clear. However, they noted that there was an increased amount of cloud to the north-west of the airport.

It was reported that, during the initial cruise, the visibility was good but the cloud base lowered as the flight progressed. The student stated that during the cruise they were maintaining about 1,200 ft above mean sea level (AMSL) with the cloud base lowering to 1,300 ft. The instructor advised they were continually checking behind them to ensure they had clear weather to return to Warrnambool if required.

Due to the deteriorating weather, the instructor decided to divert to Cobden Airport to land and wait until the weather cleared. As the aircraft approached Lake Elingamite, about 5 km south-west of Cobden (see Figure 1), the visibility reduced significantly in rain. As a result, the instructor, in the right seat, took control of the aircraft. They stated they could no longer see Cobden Airport and a decision was made to return to Warrnambool.

Figure 2: Photograph taken en route to Cobden Airport

Source: supplied

The flight crew reported that during the initial stages of the return, the visibility was good. As they got closer to Warrnambool however, the visibility reduced, and they had to descend as the cloud base again began to lower. The instructor advised they were continuously listening to the AWIS during the return. At about 1615, while approaching Warrnambool township, at approximately 450 ft AGL, the instructor slowed the aircraft and extended two stages of flap. The visibility reduced significantly and the instructor, not wanting to descend further, made the decision to climb into cloud.

Figure 3: Photograph taken at 1613 during the return to Warrnambool Airport

Source: supplied

The instructor advised that they unsuccessfully attempted to contact air traffic control (ATC) to report that they were a VFR aircraft changing category to instrument flight rules (IFR).^[10] They reported that they were having radio difficulties and this call may not have been received. Despite that, ATC responded to a call where the instructor advised they were in cloud and were requesting assistance. After clarifying the aircraft’s location and the pilot’s intentions, ATC assisted with information on the local weather, the lowest safe altitude and subsequently provided advice to keep the wings level, maintain a constant speed and to trust their instruments.

Initially the instructor maintained a shallow climb and a low angle of bank turn to remain within an area around Warrnambool known to be clear of obstacles. When they reached 3,000 ft, they turned north to ensure they did not track over water. They advised that in an attempt to fix the apparent radio problems they also switched between the two radio units in the aircraft and exchanged headsets with the student pilot. They continued the climb to 4,500 ft.

ATC identified the aircraft on radar and issued the flight crew with a heading to Avalon Airport as the pilot of a helicopter in that area had reported operating clear of cloud. During the cruise, the instructor became concerned that they would enter controlled airspace and requested a clearance at 4,500 ft, which was approved.

The aircraft exited cloud about 10 NM south-west of Avalon Airport, where the instructor requested, and was cleared for, descent to 2,500 ft. The flight then continued to Moorabbin Airport for an uneventful landing.

Context

Personnel information

Instructor

The grade three instructor held a valid Commercial Pilot Licence (Aeroplane), with a class 2 aviation medical certificate. They held an instrument rating with multi-engine aeroplane (IR-MEA), IAP 2D and IAP 3D endorsements.^[11] They had completed an instrument proficiency check in March 2020 but had not conducted any instrument flying since that date.^[12] In addition, they had never conducted instrument flying from the right seat of the aircraft.

They had accrued a total of 1,241 flying hours, having flown approximately 62 hours in the previous 90 days. 

At the time of the incident, the pilot had a self-assessed fatigue level^[13] of ‘2: very lively. Responsive, but not at peak’.

Student pilot

The student pilot held a recreational pilot licence and was training for their commercial pilot licence. They had accumulated approximately 81 hours of flying with approximately 17 hours in the previous 90 days.

Aircraft

The Piper PA-28-161 is a single engine, low wing, four seat aircraft. FPS was certified for day and night VFR operations only. The main aircraft flight instruments are located on the left side of the cockpit (Figure 4).

Figure 4: PA-28 cockpit

Source: supplied

Weather forecasts

The student received the graphical area forecast (GAF)^[14] at 0910. It was valid until 1600. The GAF was split into six different areas on the day (Figure 5). The flight was planned to traverse two of these areas: B and C.

Area C

The initial section of the flight from Moorabbin Airport was planned in area C. This area was forecast to have greater than 10 km visibility and scattered cloud between 1,600 and 3,000 ft AMSL. From 1500, cloud was forecast to increase to broken between 3,000 and 8,000 ft AMSL.

Area B

The flight was then planned to enter area B, which included Warrnambool. From 1400, the visibility in this area was forecast to reduce to 3,000 m in scattered rain with broken stratus^[15] cloud between 500 and 2,000 ft AMSL and broken stratocumulus^[16] clouds between 2,000 and 9,000 ft AMSL.

Grid Point Wind and Temperature forecast

The Grid Point Wind and Temperature forecast valid at the time of the flight, forecast the wind to be at 27 kt from 249˚ in the Ballarat area and 11 kt from 249˚ in the Warrnambool area.

No AIRMETs^[17] or SIGMETs^[18] were issued during the validity period.

Figure 5: Graphical area forecast valid for flight

Source: Bureau of Meteorology, annotated by the ATSB

Warrnambool aerodrome forecast

The TAF for Warrnambool was issued at 0445 and was valid when the student received the information at 0938. It was forecasting visibility greater than 10 km and scattered cloud with a base at 3,000 ft AGL. An INTER was forecast from 1500, where the visibility was forecast to reduce to 5,000 m in showers of rain with broken cloud at 1,000 and 2,500 ft AGL.

The Bureau of Meteorology released an amended TAF at 1243, after the aircraft had departed Moorabbin Airport. It forecast that at the time of their arrival the visibility would be greater than 10 km, with showers of rain and few^[19] cloud with a base of 1,500 ft AGL. The forecast INTER was due to commence at 1600 with visibility reducing to 5,000 m in showers of rain and a broken cloud base at 1,000 ft AGL. The crew did not receive this forecast.

At 1500, a second amended TAF was released that forecast visibility to remain greater than 10 km with showers of rain and scattered cloud with bases at both 1,000 and 2,000 ft plus broken cloud at 3,000 ft AGL. There was also a TEMPO associated with this TAF which commenced at 1500, forecasting the visibility to reduce to 4,000 m in showers of rain and broken cloud at 800 and 2,000 ft AGL.

Warrnambool airport observations

An automatic weather station (AWS) recorded actual weather conditions at Warrnambool Airport. The cloud base and amount is measured by a ceilometer, which is a device that uses a laser, or other light source, to determine the height of the cloud base. As such, it measures the cloud in one direction only and this may not give an accurate interpretation of the surrounding conditions.

The AWS recorded a SPECI^[20] report about 5 minutes before the aircraft departed Warrnambool that showed the visibility was greater than 10 km with scattered cloud at 1,100 ft and broken cloud at 1,900 ft AGL.

While the aircraft was returning to Warrnambool, the AWS recorded that the visibility was fluctuating between 5,000–9,000 m, with cloud at 900 ft AGL, varying between broken and scattered.

Moorabbin Airport forecast

The TAF current at the time of departure from Moorabbin Airport, issued at 0505, was valid for the entire flight. It forecast CAVOK conditions at the time of departure and for the return to Moorabbin.^[21] However, a new TAF was issued at 1032, before the flight departed Moorabbin, which was valid from 1100 to 2300. It also forecast conditions to be CAVOK during the flight, with deteriorating conditions associated with an INTER due to commence at 1900.

Flight planning

Civil Aviation Regulations (CAR), 239 Planning of flight by pilot in command, stated that ‘before beginning a flight, the pilot in command shall study all available information appropriate to the intended operation, and in the cases of flights away from the vicinity of an aerodrome…current weather reports and forecasts for the route to be followed and at the aerodromes to be used’.

Aeronautical Information Publication (AIP) Enroute 1.10 Flight planning stated that the forecast information must include an airport forecast for the destination and, when required, the alternate airport. It also stated that if the pre-flight information is obtained more than 1 hour prior to the estimated departure time, updated information is required.

In addition, AIP Enroute 1.1 10.7.2 Weather conditions stated that when planning a day VFR flight in a fixed wing aircraft, an alternate airport is required when conditions at the destination airport are forecast to be cloud greater than scattered below 1,500 ft or visibility less than 8 km. If a TEMPO is associated with the forecast, which reduces conditions below this requirement, then the pilot is required to plan an alternate airport or to have enough fuel to hold for 1 hour.

Visual flight rules

Civil Aviation Regulations 1988 (CAR), 172 Flight visibility and distance from cloud, outlined that flight under the VFR can only be conducted in visual meteorological conditions (VMC).^[22] Additionally, when operating at or below 2,000 ft above the ground or water, the pilot must be able to navigate by visual reference to the ground or water.

In addition to minimum visibility and distance from cloud, a pilot is also required to maintain a minimum height above the ground. CAR 157 Low flying, directs that a pilot in command must not fly the aircraft over:

• any city, town, or populous area at a height lower than 1,000 ft; or
• any other area at a height lower than 500 ft.

This does not apply if ‘through stress of weather or any other unavoidable cause it is essential that a lower height be maintained’.

Similar occurrences

Between 2011 and 2021, the ATSB was notified of 106 occurrences, where a VFR flight entered IMC. Of these, there were 13 accidents that resulted in 26 fatal injuries.

Safety analysis

Both the instructor and the student pilot advised that they assessed the weather forecasts during the pre-flight planning. They also both advised that they planned to land at Warrnambool before 1400, which was before the deteriorating weather was forecast to commence on the Warrnambool TAF. However, they did not assess the forecast deteriorating weather in area B on the GAF, which was also due to commence at 1400.

Additionally, as the flight left more than 60 minutes after the pre-flight weather forecasts were obtained, updated weather forecasts were required. However, the weather information had not changed significantly. The delayed departure and the time spent on the ground in Warrnambool both added to the likelihood of the aircraft encountering the forecast deteriorating weather.

The instructor advised that they checked the weather for the return flight while they were on the ground at Warrnambool. However, they used the TAF for Warrnambool and the surrounding airports, rather than the area forecast and Moorabbin TAF, to provide an indication of the likely weather to be encountered on return to Moorabbin. This was a missed opportunity to identify the forecast reduced visibility and low-level cloud subsequently encountered during the flight.

In addition, as the instructor planned to return to Warrnambool Airport if conditions deteriorated, they should have considered the forecast in relation to its use as a destination. As the TAF forecast a TEMPO with conditions deteriorating below the alternate minima requirements, they were required to plan for an alternate airport or have enough fuel to hold for 1 hour.

The flight crew had refuelled at Warrnambool, so the aircraft had sufficient endurance for the required holding. However, when planning to hold for 1-hour, consideration should also be given to the likely weather conditions – in this case, the conditions were forecast to have visibility reducing to 4,000 m and broken cloud at 800 ft AGL. The flight crew had experienced the rapidly changing weather environment, and consideration should have been given to how they were going to hold for 1‑hour in potentially poor weather conditions.

The instructor also did not adequately reassess the conditions at Moorabbin prior to departure from Warrnambool, however the conditions were suitable for the return flight.

Although the conditions on departure from Warrnambool were suitable for VFR flight, they soon deteriorated resulting in the decision to return. During the return to Warrnambool, the aircraft encountered forecast conditions which were no longer suitable for VFR flight and the instructor climbed the aircraft and entered cloud. The instructor had an instrument rating however, they had not practiced this skill in eleven months. In addition, the aircraft was not certified for instrument flight.

After making the decision to enter cloud, the instructor was conscious that they were not current and had never flown with reference to instruments from the right seat, which required them to use the instruments on an angle across the cockpit. Consequently, they ensured that they minimised control movements to maintain control of the aircraft. They also contacted ATC at the earliest opportunity to advise of their situation and request assistance. This ensured the instructor could concentrate on flying and maintaining control of the aircraft and also expedite the return to visual flight conditions.

Findings

ATSB investigation report findings focus on safety factors (that is, events and conditions that increase risk). Safety factors include ‘contributing factors’ and ‘other factors that increased risk’ (that is, factors that did not meet the definition of a contributing factor for this occurrence but were still considered important to include in the report for the purpose of increasing awareness and enhancing safety). In addition ‘other findings’ may be included to provide important information about topics other than safety factors.  These findings should not be read as apportioning blame or liability to any particular organisation or individual.

From the evidence available, the following findings are made with respect to the VFR flight into IMC involving Piper Aircraft PA-28, VH-FPS, near Warrnambool, Victoria on the 25 February 2021.

Contributing factors

• While conducting preparation for the flight, neither the instructor nor the student pilot identified the forecast deteriorating weather in the Warrnambool area.
• Prior to departure from Warrnambool, the instructor did not analyse either the Warrnambool or Moorabbin aerodrome forecasts for their suitability as destination airports. This probably resulted in them selecting Warrnambool as an alternate airport, despite the forecast temporary deterioration, and encountering poor weather conditions during the return to Warrnambool.
• Conditions reduced below that required for visual flight resulting in the VFR‑certified aircraft entering instrument meteorological conditions.

Other findings

• After entering instrument meteorological conditions (IMC), the instructor maintained control of the aircraft and requested assistance from air traffic control.

Safety actions

Whether or not the ATSB identifies safety issues in the course of an investigation, relevant organisations may proactively initiate safety action in order to reduce their safety risk. All of the directly involved parties are invited to provide submissions to this draft report. As part of that process, each organisation is asked to communicate what safety actions, if any, they have carried out to reduce the risk associated with this type of occurrences in the future.

Safety action by Moorabbin Aviation Services

As a result of this occurrence, the operator have developed a:

• weather information board which displays synoptic charts, relevant TAFs and grid point wind and temperature (GPWT) chart for the day at the Moorabbin base
• Warrnambool PowerPoint presentation for dual and subsequent solo exercises to emphasis weather in that region of Victoria and Bass Strait
• supervision policy in the Training Management Manual to facilitate varying supervision based on the experience level and proven competency of the junior instructors and other circumstances which may challenge the junior instructor’s skill set
• company policy to provide organisational support for flight crew required to stay away overnight due to adverse weather, aircraft unserviceability or pilot incapacity/fatigue, including arrangement and payment of transport and accommodation if required. This policy will be promoted through both staff and student levels
• program on effective decision making to be delivered to all staff.

Sources and submissions

Sources of information

The sources of information during the investigation included the:

• flight crew
• Moorabbin Aviation Services
• Bureau of Meteorology
• Airservices Australia

Submissions

Under section 26 of the Transport Safety Investigation Act 2003, the ATSB may provide a draft report, on a confidential basis, to any person whom the ATSB considers appropriate. That section allows a person receiving a draft report to make submissions to the ATSB about the draft report.

A draft of this report was provided to the following directly involved parties:

• flight crew
• Moorabbin Aviation Services
• Bureau of Meteorology
• Civil Aviation Safety Authority
• Airservices Australia

Submissions were received from:

• the instructor
• Moorabbin Aviation Services
• Civil Aviation Safety Authority

The submissions were reviewed and, where considered appropriate, the text of the report was amended accordingly.

Purpose of safety investigations The objective of a safety investigation is to enhance transport safety. This is done through: identifying safety issues and facilitating safety action to address those issues providing information about occurrences and their associated safety factors to facilitate learning within the transport industry. It is not a function of the ATSB to apportion blame or provide a means for determining liability. At the same time, an investigation report must include factual material of sufficient weight to support the analysis and findings. At all times the ATSB endeavours to balance the use of material that could imply adverse comment with the need to properly explain what happened, and why, in a fair and unbiased manner. The ATSB does not investigate for the purpose of taking administrative, regulatory or criminal action. Terminology An explanation of terminology used in ATSB investigation reports is available here. This includes terms such as occurrence, contributing factor, other factor that increased risk, and safety issue. Publishing information  Released in accordance with section 25 of the Transport Safety Investigation Act 2003 Published by: Australian Transport Safety Bureau © Commonwealth of Australia 2021 Ownership of intellectual property rights in this publication Unless otherwise noted, copyright (and any other intellectual property rights, if any) in this report publication is owned by the Commonwealth of Australia. Creative Commons licence With the exception of the Coat of Arms, ATSB logo, and photos and graphics in which a third party holds copyright, this publication is licensed under a Creative Commons Attribution 3.0 Australia licence. Creative Commons Attribution 3.0 Australia Licence is a standard form licence agreement that allows you to copy, distribute, transmit and adapt this publication provided that you attribute the work. The ATSB’s preference is that you attribute this publication (and any material sourced from it) using the following wording: Source: Australian Transport Safety Bureau Copyright in material obtained from other agencies, private individuals or organisations, belongs to those agencies, individuals or organisations. Where you wish to use their material, you will need to contact them directly.

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1. Visual flight rules (VFR): a set of regulations that permit a pilot to operate an aircraft only in weather conditions generally clear enough to allow the pilot to see where the aircraft is going.
2. Gender-neutral plural pronouns are used throughout the report to refer to an individual (i.e. they, them and their).
3. Cloud cover: in aviation, cloud cover is reported using words that denote the extent of the cover – ‘scattered’ indicates that cloud is covering between a quarter and a half of the sky.
4. INTER: an intermittent deterioration in the forecast weather conditions, during which a significant variation in prevailing conditions is expected to last for periods of less than 30 minutes duration.
5. Cloud cover: ‘broken’ indicates that more than half to almost all the sky is covered.
6. Eastern Daylight-saving Time (EDT): Coordinated Universal Time (UTC) + 11 hours.
7. Hood: a devise used to block out visual reference to the ground during flight training.
8. TEMPO: a temporary deterioration in the forecast weather conditions, during which significant variation in prevailing conditions are expected to last for periods of between 30 and 60 minutes.
9. Graphical Area Forecast (GAF) provides information on weather, cloud, visibility, icing, turbulence and freezing level in a graphical layout with supporting text. These are produced for 10 areas across Australia, broadly State-based.
10. Instrument flight rules (IFR): a set of regulations that permit the pilot to operate an aircraft to operate in instrument meteorological conditions (IMC), which have much lower weather minimums than visual flight rules (VFR). Procedures and training are significantly more complex as a pilot must demonstrate competency in IMC conditions while controlling the aircraft solely by reference to instruments. IFR-capable aircraft have greater equipment and maintenance requirements.
11. When flying a 2D instrument approach (IAP 2D), the pilot uses instrument displays that provide lateral (directional) navigation information, for a 3D (IAP 3D) approach the pilot uses instrument displays that provide both lateral and vertical navigation information.
12. Pilots are required to have conducted a flight of at least 1-hour duration under the IFR within the previous 6 months before conducting a single-pilot IFR flight.
13. The ATSB uses the Samn-Perelli fatigue scale from 1 (Fully alert. Wide awake. Extremely peppy) to 7 (Completely exhausted. Unable to function effectively. Ready to drop).
14. Graphical Area Forecast (GAF) provides information on weather, cloud, visibility, icing, turbulence and freezing level in a graphical layout with supporting text. These are produced for 10 areas across Australia, broadly State-based.
15. Stratus clouds are low-level clouds characterized by horizontal layering with a uniform base, as opposed to convective or cumuliform clouds that are formed by rising thermals.
16. A stratocumulus cloud, occasionally called a cumulostratus, characterised by large dark, rounded masses, usually in groups, lines, or waves.
17. AIRMET provides advice on deteriorating conditions, not already included in the relevant Graphical Area Forecast (GAF). AIRMETs are complimentary to the routine issue and correction of GAFs.
18. A SIGMET provides a concise description concerning the occurrence or expected occurrence, in areas over which meteorological watch is being maintained, of en route weather phenomena that are potentially hazardous to aircraft.
19. Cloud cover: ‘few’ indicates that up to a quarter of the sky is covered.
20. SPECI is used to identify special observations: i.e. observations when conditions are below specified criteria, or when there have been significant changes since the previous report.
21. Ceiling and visibility okay (CAVOK): visibility, cloud and present weather are better than prescribed conditions. For an aerodrome weather report, those conditions are visibility 10 km or more, no significant cloud below 5,000 ft, no cumulonimbus cloud and no other significant weather.
22. Visual Meteorological Conditions (VMC): an aviation flight category in which visual flight rules (VFR) flight is permitted – that is, conditions in which pilots have sufficient visibility to fly the aircraft while maintaining visual separation from terrain and other aircraft.