Mode of transport
Occurrence ID
AB-2023-007
Brief status
Occurrence date
Report release date
Occurrence category
Aviation occurrence type
Location
near Parafield Airport
Injury level
Occurrence Briefs are concise reports that detail the facts surrounding a transport safety occurrence, as received in the initial notification and any follow-up enquiries. They provide an opportunity to share safety messages in the absence of an investigation.

What happened

On 6 October 2023, at about 2200 local time, the pilot of a Lancair IV-PT departed Parafield Airport, on a private flight under the instrument flight rules,[1] to Whyalla, South Australia.

The pilot had been awake for 16 hours when they arrived at the airport to collect the aircraft from a maintenance organisation, who had performed maintenance on the aircraft to rectify a hydraulic leak.

The pilot reported they conducted a thorough pre-flight inspection and completed ground runs prior to departure.

During the take-off run, the pilot detected abnormal airspeed fluctuations and rejected the take-off. The pilot backtracked and commenced a second take-off. The pilot noted that the airspeed indications appeared normal, and rotated when the aircraft reached 85 kt.

During initial climb, the pilot observed the airspeed indicator was stuck between 80–90 kt and the altimeter was fluctuating between 300–800 ft. The pilot ensured that they maintained terrain clearance by tracking the assigned standard instrument departure (SID), confirming the engine was set to a known power setting and maintaining a steady attitude.

The pilot contacted the Adelaide approach controller and advised that they had unreliable airspeed and altitude indications and initially requested an immediate return to Parafield. However, recognising the importance of maintaining a higher airspeed to prevent a stall, changed the request to divert to Adelaide Airport which had a longer, wider runway. The pilot was also mindful that there were no emergency services at Parafield, whereas these services would be available at Adelaide, to assist in the event of an accident.

As requested by the pilot, the approach controller provided the pilot with the aircraft’s transponder altitude and the aircraft’s groundspeed,[2] calculated from the secondary radar. However, with no information regarding wind speed or direction, the pilot was unable to determine their indicated airspeed.[3]

As the aircraft approached the Adelaide Hills, the pilot was cognisant that the lowest safe altitude (LSALT)[4] was 3,800 ft in this area.  At this point, the pilot recalled having a handheld GPS unit that was independent of the aircraft’s static system, and it indicated that the aircraft was maintaining 4,000 ft. However, when the controller queried if the pilot could see the terrain, the pilot replied that they could not, resulting in the controller offering a coastal visual approach.

The pilot had concerns flying over the ocean as at night they would have no visual cues over the water; however, the controller suggested the city lights could be used as a reference point and another aircraft in the vicinity advised that conditions along the coast were clear. A further aircraft also relayed that the wind conditions were calm, which would aid the pilot in determining an approximate indicated airspeed.

The pilot further considered that they were flying over an urban area and in the event of an accident this may present dangers to people below. Consequently, they elected to fly the coastal approach for runway 12 at Adelaide Airport.

A short time later, the pilot could see Adelaide Airport and recognised they were too high for the approach, which was confirmed by the controller. The pilot conducted an orbit to descend and configured the aircraft for landing.

The pilot established the aircraft on the PAPI,[5] and kept the aircraft’s power higher than normal to maintain a faster airspeed to minimise the risk of a stall. This resulted in a prolonged flare and touching down about one third along runway 12.  Emergency services were in attendance but were not required.

Post-flight, the aircraft’s pitot static tubing was found to be cracked, and black debris was also found throughout the system. It was unable to be determined if this was a result of the previous maintenance or an isolated fault.

Safety action

The pilot advised that following this incident, they have added a data field on the aircraft’s Garmin screen that contains the handheld GPS altitude.

Safety message

There are several key safety messages that arise from this occurrence.

  • If you find a maintenance discrepancy and find yourself saying that it is ‘probably’ okay to fly anyway, you need to revisit the consequences (FAA, 2023). The safest thing to do is have the issue corrected prior to taking off.
  • However, if you do encounter unreliable airspeed indications during the flight, the immediate response is to maintain control with a known power setting and pitch attitude producing known performance, even if indications of that performance are uncertain (CASA, 2022). There have been a number of reported occurrences where potentially severe consequences were avoided by a pilot’s decision to seek assistance from air traffic control or nearby flight crew.
  • Fatigue makes a pilot less vigilant and more willing to accept a lesser performance level than normal, and they will often begin to show signs of poor judgement (CASA, 1999). Pilots must manage fatigue risk including not operating an aircraft if they feel that they are unfit due to fatigue or likely to become so (CASA, 2023).

Acknowledgement

The ATSB acknowledges the valuable assistance provided during this occurrence by the Adelaide approach controller, and other aircraft in the vicinity, who relayed information and acted as a calming influence for the incident pilot.

About this report

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, no investigation has been conducted and the ATSB did not verify the accuracy of the information. A brief description has been written using information supplied in the notification and any follow-up information in order to produce a short summary report and allow for greater industry awareness of potential safety issues and possible safety actions.

References

Civil Aviation Safety Authority, Instrument Failure: the test of trust, Flight Safety Australia, 2022, Canberra.

Civil Aviation Safety Authority, Fatigue management explained 2023, Canberra.

Civil Aviation Safety Authority, Pilot Fatigue and the Limits of Endurance, Flight Safety Australia, 1999, Canberra.

Federal Aviation Administration Pilot’s Handbook of Aeronautical Knowledge, Chapter 2: Aeronautical Decision Making, 2023, Washington.


[1] Instrument flight rules (IFR): a set of regulations that permit the pilot to operate an aircraft 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.

[2] An aircraft’s horizontal speed relative to the ground.

[3] Indicated airspeed is used by pilots as a reference for all aircraft manoeuvres.

[4] The lowest altitude which will provide safe terrain clearance at a given place.  

[5] Precision Approach Path Indicator (PAPI): a ground-based system that uses a system of coloured lights used by pilots to identify the correct glide path to the runway when conducting a visual approach.

Aircraft Details
Departure point
Parafield Airport, South Australia
Destination
Whyalla Airport, South Australia
Model
Lancair IV-PT
Operation type
Part 91 General operating and flight rules
Damage
Nil
Manufacturer
Amateur Built Aircraft