When working airside it is important to recognize the signs of fatigue and be aware of how it could affect your performance on the job.
Managing fatigue is everyone’s responsibility. Together, employees and employers have clear responsibilities to manage fatigue.
Fatigue is a safety risk that needs to be managed. When working airside it is important to recognize the signs of fatigue and be aware of how it could affect your performance on the job.
Fatigue can significantly delay your response and reaction times, impair reasoning, reduce vigilance and affect hand- eye coordination.
But the greatest single threat is being unaware that it is happening.
Fatigue is brought on by the amount of time you’ve spent on the job and the type of work you have been doing. It is also attributable to what you are doing when not at work. If you have another job, especially one that requires long hours and involves strenuous activity or long periods of concentration, you’re more prone to fatigue when at work.
Managing fatigue is everyone’s responsibility.
What are the effects of fatigue?
Fatigue reduces your ability to concentrate. Specifically, the effects include:
slowed reaction times
reduced vigilance
slower mental abilities
memory problems
poor communication
reduced alertness
poor decision-making
fixation on a single task
actually falling asleep while working.
Tips for countering fatigue
Be conscious of the quality of your sleep – if your sleep quality has been poor, it may not be safe to keep working.
When assessing your potential fatigue levels, take into account all activities you do throughout your day.
Proper nutrition and plenty of water helps keep you alert:
minimize fatty and high-sugar foods
don’t rely on caffeine (coffee, energy drinks) as it only provides short-term relief from the effects of fatigue.
Remember, getting enough quality sleep is essential to avoiding fatigue.
What’s your fatigue risk?
Use the following checklist to give yourself an objective assessment of your fatigue risk:
Did you have less than eight hours sleep last night?
Have you missed out on adequate sleep over the previous nights?
Has your sleep been disrupted?
Have you been awake and/or at work for an extended period?
Have you had less than six hours sleep in the last 24 hours (or less than 14 hours sleep in the last two days)?
Have you had a recent illness or injury?
Are you affected by medication, other drugs or alcohol?
If your answer to one or more of these questions is yes or even maybe, you’re at a higher risk of fatigue.
Share this information with your co-workers and family. Ask them to keep an eye on your performance. Do the same for others you work with.
Managing fatigue is everyone’s responsibility. Together, employees and employers have clear responsibilities to manage fatigue.
Employers have a duty of care to provide safe work schedules that permit adequate time for an employee to sleep, rest and recover as well as fulfil their social and domestic responsibilities.
Employees also have a duty of care to use their time away from work to get enough sleep and recovery time so they can complete their work duties safely and responsibly.
Two separate incidents show how important it is to avoid distractions, such as mobile phones when driving airside.
The ATSB reminds airport workers to always remain focused during airside operations.
Radio communications phraseology should be clear, concise and unambiguous.
Two separate incidents investigated by the ATSB show how important it is to communicate clearly and avoid distractions, such as mobile phones when driving airside.
An incident at Mackay Airport highlighted the potential distraction presented by portable communication devices, especially in the dynamic airside environment.
On 29 June 2012, a Piper PA-31 Navajo aircraft, took off from runway 05 at Mackay Airport. At that time, an Airport Safety Officer (ASO) was conducting an airfield runway and lighting inspection in an airfield safety vehicle and moving in a north-westerly direction along runway 32. Despite an earlier air traffic control instruction to hold short of runway 05, the ASO was distracted by a telephone call and continued along runway 32, crossing runway 05. The Piper PA-31 passed over the airfield safety vehicle by an estimated vertical distance of 30 feet.
Too close for comfort!
It is important to remain alert and to be mindful of the potential distraction presented by portable communication devices.
In another incident that same month, an airport safety vehicle at Perth airport entered runway 21 without a clearance during the operation of low visibility procedures. Prior to entering the runway, an air traffic controller used non-standard phraseology to instruct the vehicle to conduct a runway visibility check.
The Tower controller did not know that there had been a handover between airport operations officers and thought he was talking to the same person as had been operating earlier.
In response to this incident, the Perth Airport, the operator of the vehicle, conducted a workshop for airport operations officers (AOOs) to reinforce the importance of seeking clarification of implied or unclear instructions from air traffic control (ATC).
In June 2015, Airservices Australia published the fifth edition of An Airside Driver's Guide to Runway Safety(Opens in a new tab/window). This publication identified a range of safety measures intended to help reduce the likelihood of runway incursions, including information about situation awareness and communications. This publication also highlighted the importance of scanning runways before entering or crossing a runway.
The ATSB reminds airport workers to always remain focused during airside operations. It is important to remain alert and to be mindful of the potential distraction presented by portable communication devices.
Radio communications phraseology should be clear, concise and unambiguous. Drivers of airport vehicles are urged to seek clarification of ATC instructions if there is any doubt at all about the content or intent of the instruction.
Pilot fatigue contributed to an incident where an Avro 146 jet received two separate warnings for flying below the minimum altitude.
Don’t let lack of sleep affect your fitness to fly.
Pilot fatigue contributed to an incident where an Avro 146 jet received two separate warnings for flying below the minimum altitude, according to an ATSB report.
The incident occurred on 23 June 2015 when the captain and first officer of the Jet Express aircraft were flying from Perth to Granny Smith Airport, north of Kalgoorlie Western Australia. The aircraft had five crew and 67 passengers on board.
While approaching Granny Smith Airport, the captain observed the radio altimeter (RADALT) indicating 500 ft and the electronic ground proximity warning system (EGPWS) called ‘500’, both indicating the aircraft was 500 ft above the ground. Shortly afterwards, the crew received an EGPWS ‘DON’T SINK’ warning. The first officer then observed the RADALT indicating 380 ft and the vertical speed indicator showing about 100 ft per minute descent. The captain immediately applied nose-up pitch and increased the thrust. The aircraft climbed and the captain levelled the aircraft off to remain clear of cloud. The crew then received a second ‘DON’T SINK’ warning. The first officer noted the RADALT indicating 410 ft and the captain immediately initiated a go-around, climbing to 4,000 ft AMSL.
Due to the time spent operating with the aircraft in the approach configuration, and the possibility of holding required in Perth, the captain elected to divert and land at Kalgoorlie.
In the 24 hours before signing on for duty, the captain had about three hours’ sleep and felt irritable, with poor concentration, heavy eyes, and slow thinking processes. The captain believed decision-making had been affected by lack of sleep.
This incident serves as a warning to pilots on how fatigue can affect performance. In fact, less than six hours sleep in the previous 24 hours is associated with degraded operational performance and increased error rates.
The amount of fuel on board should be thought of, not as a quantity, but as a flight time.
Fuel exhaustion happens when an aircraft runs out of usable fuel before the flight is finished.
Fuel exhaustion occurrences are normally either the result of a gross error in the fuelling of an aircraft before flight, or the result of a number of seemingly minor aspects of fuel planning and management during the flight.
Accidents involving fuel exhaustion often happen close to the flight’s destination. If fuel exhaustion occurs when the aircraft is close to landing, it may offer the pilot less time and opportunity to successfully manage the situation.
In April 2010, the pilot of a light aircraft was conducting the fifth flight since refuelling, when the engine lost power while sight-seeing over Hobart, Tasmania. The pilot conducted a forced landing onto the Brooker Highway, resulting in substantial damage to the aircraft.
The pilot reported that he had used a dipstick to assess that there was sufficient fuel for the flight, and that the fuel quantity indicator provided a similar indication of fuel quantity, showing the tank was about half full. Unfortunately, the pilot used an incorrect (but not uncommon) method of using the dipstick that resulted in an over-reading of the fuel onboard. Furthermore, a close inspection of the aircraft’s flight and fuel log would have revealed that the fuel gauge and the dipstick indications showed a fuel usage that was half the expected usage.
What we found
The ATSB investigation AO-2010-025 found that the power loss was due to exhaustion of the aircraft's fuel supply and that a number of factors worked against the pilot, some of which were outside his control.
The amount of fuel on board should be thought of, not as a quantity, but as a flight time.
Cross-checking the dipstick reading against the fuel gauge indication was an effective method for spotting errors, however, a quick mental calculation would have shown a significant discrepancy between the indicated fuel quantity and the expected fuel usage. The discrepancy could have alerted the pilot that something was wrong with the available fuel quantity information.
Safety message
Certain types of flight regularly carry just enough fuel for the flight, with little margin. Flying schools and gliding towing operations may only refuel aircraft after two or three flights, so the last flight before refuelling can have less fuel margin. Charter operations may be flying with minimum fuel required because a flight’s profitability will depend on carrying the maximum payload, which means no unnecessary fuel be carried. Such operations will be more vulnerable to any inaccuracies in the pilot’s knowledge about the amount of fuel on board. However, fuel exhaustion accidents and incidents occur in all types of aviation operations. They are normally related to a lack of awareness of information that is readily available at the pre-flight planning stage. This includes both the amount of fuel on board, and the rate of fuel consumption.
The chance of fuel exhaustion is reduced if the pilot accurately determines the amount of fuel on board prior to starting. This should entail the use of a fuel quantity cross-check using a number of sources, including:
fuel quantity gauges
dipsticks
flowmeters/ totalisers
calculations from previous refuels and fuel usage, (regularly checked for accuracy).
Fuel exhaustion happens when there is no useable fuel remaining to supply the engine(s).
The amount of fuel on board should be thought of, not as a quantity, but as a flight time. For a consistent combination of altitude, power setting and mixture setting, the fuel burn will be constant, but changing winds and deviations due to weather conditions will vary the groundspeed and therefore the range. Your fuel status should be regularly updated, at least every hour, to ensure you maintain an adequate reserve1.
An aircraft that is carrying only just enough flight fuel2 for the planned flight, but which encounters unanticipated headwinds and perhaps has to fly at a lower level is eating into its fuel reserves. Those reserves are there to be used in unforeseen circumstances and many aircraft arrive safely at their destination having used a portion of the allocated reserve fuel. However an aircraft’s fuel supply should not reach a state where, upon arriving at its destination, it can accept no further delay.
1. Reserve fuel refers to the required fuel, in addition to flight fuel, that is not planned for normal use, but remains available for unplanned events where all other useable fuel has been consumed. This fuel is to be used only when there is no other safer alternative.
2. Flight fuel refers to all the fuel that is expected to be used during the planned flight, including holding fuel and fuel for planned diversions.
Conclusion
Fuel exhaustion is more likely to occur on flights when there is little flight fuel margin, that is, landing with just reserve fuel on board. In these circumstances, particular attention to detail in fuel management is warranted. The chance of fuel exhaustion can be reduced by:
using more than one source of information to obtain consistent results about the fuel on board before flight
the use of a consistent procedure that is regularly checked to know the exact rate of fuel consumption
monitoring the flight to ensure that sufficient fuel will remain on board in the event of unplanned delays.
Carburettor icing can occur even in relatively warm conditions - the higher the humidity, the more likely it is that ice will form in the air-intake system.
Carburettor icing can happen at temperatures of up to 38 degrees Celsius.
Carburettor heat should be applied immediately when an engine runs roughly.
Carburettor icing can occur even in relatively warm conditions - the higher the humidity, the more likely it is that ice will form in the air-intake system.
Carburettor icing likely contributed to an accident on 14 July 2015, when the pilot of a Robinson R44 helicopter was conducting aerial mustering operations on a property near Alice Springs.
The pilot felt a small vibration, and initially thought it was due to loose tape on the main rotor blade. The pilot looked for a suitable landing site, but the vibration increased significantly.
Carburettor icing can happen at temperatures of up to 38 degrees Celsius – it is less likely at very cold temperatures.
As the helicopter descended, the pilot maneuvered it through a gap between trees, and pushed the cyclic forward to maintain airspeed. The pilot lowered the collective and noticed the engine seemed to go very quiet. The low rotor revolutions per minute warning horn sounded. The pilot made a radio call to advise another pilot operating nearby that the helicopter was going down. The pilot then flared the helicopter to try to cushion the landing impact. The right skid touched down first, and the helicopter rolled onto its right side.
The pilot sustained minor injuries, and the helicopter was substantially damaged. The weather was fine with no visible signs of moisture and the pilot did not turn the carburettor heat on at any stage during the flight.
According to the Carburettor Icing Probability chart, current conditions indicated a high probability of serious carburettor icing at descent power. At the time it was 12 degrees Celsius with relatively high humidity of 40 – 45 per cent.
The icy facts:
Carburettors cause evaporation, which cools the air.
Carburettor icing can happen at temperatures of up to 38 degrees Celsius – it is less likely at very cold temperatures.
Carburettor icing is more likely at partial power settings because of the cooling effect of a partly closed throttle butterfly.
Even when undertaken by appropriately qualified pilots, night flight clearly presents an added level of complexity.
This case study from the Avoidable Accidents Series - Visual flight at night accidents shows that even when undertaken by appropriately qualified pilots, night flight clearly presents an added level of complexity.
In August 2011, the pilot of a Twin Squirrel AS355F2 helicopter and two film crew were travelling to various locations in the Lake Eyre region of South Australia for a television documentary. On the second day, they arrived at an island in the Cooper Creek inlet at about 1715 to meet and interview a tour group.
The pilot and film crew departed the island at about 1900. It was after last light and, while there was no low cloud or rain, it was a dark night. The moon had not risen and there was no visible horizon. Apart from the tour group’s campfire on the island, there was no other source of terrestrial lighting, and there would have been very little ambient illumination from any sources other than stars. Witnesses reported that the helicopter initially climbed vertically while moving rearwards.
This was most likely to maintain a visual reference to the campfire, which was the only available ground light source. The witnesses then observed the helicopter depart in an easterly then north-easterly direction. This was contrary to what they expected as they understood that the crew were returning to their accommodation at Muloorina Station, which was to the south.
Even when undertaken by appropriately qualified pilots, night flight clearly presents an added level of complexity.
The helicopter levelled off at 1,500 ft AMSL and then commenced a turn to the right. As the helicopter had initially travelled in the wrong direction, it is probable that the pilot engaged in programming the helicopter's global positioning system (GPS) for their journey to their accommodation during this turn. Twelve seconds after beginning the turn, the helicopter started descending with the bank angle increasing. Based on the GPS data and flight path estimations, it was calculated that the helicopter impacted terrain at about 1902, about 38 seconds after it started descending. Wreckage examination indicated that the helicopter impacted terrain in a 90° right-side low attitude.
The pilot had been flying for over 30 years as a commercial pilot with over 16,000 hours experience, mostly in helicopters. He also had a night visual flight rules (VFR) rating and had 483 night flying hours in total, but only 3.4 hours in the last 12 months, and 30 hours in the past 4 years. Although he had some instrument flight time, this was more than 30 years before the accident. As such, he probably did not have enough recent night flying experience nor the level of instrument proficiency at the time of the accident needed for the very dark conditions.
The ATSB investigation concluded that the pilot probably became spatially disoriented after initiating the right turn and did not recognise the descent and increasing bank angle in sufficient time to recover.
Lessons learnt
In very dark conditions, visual meteorological conditions (VMC) essentially equates to instrument flight rules (IFR) in terms of available external visual information. Pilots need to reassess their night flying experience, recency and proficiency before every night flight, taking into account the level of instrument flying required based on the level of darkness.
Any pilot can become spatially disoriented given the right conditions. Distractions and high workload can inadvertently remove attention away from monitoring instruments, reducing the chance of recognising spatial disorientation.
The ATSB advises all operators and pilots considering night flights under the VFR to systematically assess the potential for the flight to encounter dark night conditions by reviewing weather conditions, celestial illumination and available terrain lighting. If there is a likelihood of dark night conditions, the flight should be conducted as an instrument flight rules (IFR) operation, or conducted by a pilot who has an IFR-equivalent level of instrument flying proficiency and in an aircraft that is equipped to a standard similar to that required under the IFR.
Conclusion
Data from accidents associated with the risks from night visual flight indicate that they can affect pilots at all stages of experience or qualification, in any type of aircraft. Pilots do not become immune from these risks as experience increases. The harsh outcomes of night accidents can be seen in the photos throughout this booklet. Three in four accidents involving visual flight at night have fatal outcomes.
The risks associated with night visual flying cannot be avoided—they must be understood, identified and managed. Control problems can be identified by cross-referencing information from flight instruments. They can be managed by focussing on aircraft control and using the most reliable information source. The risks from controlled flight into terrain can be managed by calculating LSALTs (lowest safe altitude), knowing terrain elevation during the cruise, and knowing where hills and obstacles are in the circuit area during take-off and landing. The knowledge can be obtained by thorough pre-flight preparation, by accurate horizontal navigation to know where you are, and accurate vertical navigation to know your distance from obstacles below. Everything is more difficult to see at night. Terrain and obstacles are often not illuminated, and it is more difficult to detect cloud. When it is time to fly low enough to land, a detailed plan of how to avoid all obstacles along the expected flightpath is necessary to maintain safety.
Visual night flying is sufficiently different from both day visual flight and (except in very dark conditions) instrument flight that it needs to be treated as a separate skill in its own right. It requires a disciplined integration of two very different skill sets of instrument flight and degraded visual flight to develop sufficient situational awareness to enable safe flight. To maintain these skills, a pilot needs to have enough recent experience and practice. When flying over land or oceans without light sources, on dark nights with no visible moon, visual flight at night is essentially the same as instrument flight.
Before every night flight, systematically assess the potential for the flight to encounter dark night conditions by considering weather conditions, celestial illumination and available terrestrial lighting. Only fly in environments that do not exceed your capabilities. In very dark conditions, consider following instrument procedures if you are rated or avoid areas with limited terrestrial lighting if you are not.
In night visual flight, there is more chance of any pilot becoming influenced by illusions. Have a coping strategy in place, and be prepared to revert to instrument flight to recover from any spatial disorientation.
Three occupants of an R44 helicopter walked away uninjured, after it struck a powerline.
Wirestrikes continue to pose serious risks to pilots and passengers.
Three occupants of an R44 helicopter walked away uninjured, after it struck a powerline 142 km west-south-west of Adelaide, South Australia, on 29 March 2015.
The pilot of a Robinson R44 helicopter, was engaged in herbicide dispensing operations near Marion Bay on the Yorke Peninsula in South Australia.
The powerline was not included in information provided to the pilot by local sources, or mapped on the helicopter’s data logger. The pilot had also flown over the area before starting aerial spraying, without sighting the single wire, which ran perpendicular to two other identified, parallel powerlines.
The helicopter struck the wire, while operating at low level spraying noxious weeds with herbicide. The main rotor blade contacted the wire first, followed by the tail rotor blades. The helicopter sustained substantial damage.
Wirestrikes pose an on-going problem to aerial agricultural operations.
This accident provides a reminder of the need for consistency in aerial surveys for powerlines, the establishment of standardised procedures for their identification and the need for independent assessment of their presence.
Single wires can be difficult to see and occur in the most unexpected places in rural areas. ATSB research article Avoidable accidents No. 1 - Low level flying provides additional information on wire hazards associated with flight below 500’.
This accident highlights the risks associated with unsealed airfields.
This accident highlights the risks associated with unsealed airfields.
The pilot and two passengers of a Cessna 182 aircraft suffered minor injuries, when the aircraft sank rapidly just before landing. It then landed heavily, bounced into the air, landed again, sank into soft ground, and flipped over.
The property where the airstrip was located had received about 100 mm of rain over a period of two weeks, which had stopped about a week prior to the accident. The surface of the runway appeared to be firm, but a soft layer extended beneath it. The hard landing combined with the soft surface led to the landing gear digging in and flipping the aircraft over. The pilot was unsure what had caused the aircraft to sink.
This incident highlights the importance of the identification and management of risks associated with unsealed airfields. Potential hazards such as changes in the runway surface following rain can be hard to detect. Changes in the runway surface can adversely affect the outcome of a hard landing.
This tragic accident highlights the dangers of flying visually in poor weather.
This tragic accident from the Avoidable Accident series highlights the dangers of flying visually in poor weather.
The pilot of a Cessna 337 Skymaster was conducting a private VFR flight from Moorabbin Airport, Victoria to Merimbula, NSW. The pilot, who was only qualified to operate in VMC, had indicated that he would be tracking along the coast at low level. The forecast weather included isolated showers or thunderstorms over the sea and coast, and low cloud over the sea/exposed coast. The low cloud was expected to be broken stratus between 800 ft and 2,000 ft. Visibility was quoted as reducing to 3 km in thunderstorms with rain and 6 km in showers of rain.
About 30 minutes after departing Moorabbin, people on a beach south-east of Venus Bay heard and then suddenly saw the aircraft emerge from fog at low level, flying above the water line on the beach with the wings level. Within seconds it turned right at a steep angle of bank while maintaining height and headed out to sea before disappearing from sight into the fog. The witnesses reported no apparent problem with the engines and the aircraft appeared to be under control. About 2 seconds after the aircraft disappeared from view, they heard a ‘bang’ and then silence.
Two days later, wreckage of the aircraft and three of the deceased occupants were found washed up on the beach. The pilot was not found.
The investigation concluded that while manoeuvring over water at low level in conditions of reduced visibility, the pilot probably became spatially disorientated and inadvertently descended into the water.
By turning away from the land in the foggy conditions, the pilot would have encountered a featureless, grey environment with no visible horizon, making it extremely difficult for him to judge the aircraft’s attitude and/or height.
It should be accepted that flying under the VFR will not always enable you to reach your planned destination. Weather often does not act as the forecast predicts.
It should be accepted that flying under the VFR will not always enable you to reach your planned destination. Weather often does not act as the forecast predicts. You must have alternatives available and you must be prepared to use them — even if it means returning to your departure point.
In forecast marginal weather, careful pre-flight planning is essential and must include a thorough analysis of the latest weather forecasts and consideration of your available options. Those options should be evaluated while en route to ensure you have an alternative course of action available which provides for a safe landing.
When deciding on whether it is safe to fly you should consider not only the route to be flown, the prevailing weather and aircraft serviceability, but your own physical and emotional fitness and flying experience. In other words, to be a competent pilot you must know and fly within your own limitations. Adhering to a pre-flight ‘personal minimums’ checklist will go a long way toward keeping you safe. For example, the decision to turn back or divert will be easier if you have decided in advance what your personal minimum VFR flying altitude will be. That minimum altitude may well be much more conservative than the legal requirement.
A ‘personal minimums’ checklist, included in the CASA publication ‘Flight Planning — always thinking ahead’, will help you control and manage risk by identifying risk factors and allowing you to fly with less stress and less risk.
A Mooney M20 pilot in the United States recently reported that a tablet computer interfered with the aircraft’s compass, resulting in the aircraft being 15 degrees off its assigned heading.
If you‘ve had a similar occurrence or experienced an aviation safety hazard you’d like to share, provide a comment below.
A Mooney M20 pilot in the United States recently reported that a tablet computer interfered with the aircraft’s compass, resulting in the aircraft being 15 degrees off its assigned heading.
The pilot was flying on instruments in cloud and being radar vectored when an air traffic controller advised the crew they were 15 degrees off their assigned heading. The pilot revised the heading indicator to reflect the 15 degree variation and the aircraft landed safely.
An investigation revealed the interference was caused by a tablet computer which was placed on the glare shield during the flight. The tablet computer has magnets inside which have been known to cause up to 30 degrees interference when placed in close proximity to the compass.
The pilot reported the incident to the Aviation Self Reporting Scheme (ASRS) in the United States.
