This review of agricultural aviation accidents reported to BASI in the period 1985 to 1992 indicates:
there were no significant reductions in the number or rate of accidents
there were higher accident and fatal accident rates than for other GA operations
the majority of accidents occurred in the agricultural work phase of flight, although the taxi and take-off phase accounted for a significant percentage of accidents
factors related to pilot perception and operational decision were most frequent
accident prevention programs should address:
failure to see and avoid objects or obstacles;
inadequacy of pre-flight preparation and planning; and
distraction from operation of aircraft.
The Director of BASI reiterated the points highlighted in this review when addressing the 1994 annual conference of the Aerial Agricultural Association.
There were a total of 546 marine occurrences reported to the Australian Transport Safety Bureau from 2005 to 2010. There were significant decreases in reported occurrences in 2008 and 2010; however, the number of serious incidents remained fairly constant for the duration of the period. The number of accidents has decreased from eight each year from 2005 to 2007 to three each year from 2008 to 2010, which reflects the decrease in fatal accidents and people missing during the second half of the period. Injuries sustained were mainly to one person in each occurrence; however, there were occasional occurrences where more than one person was injured.
The West Australian and Queensland coasts had the most marine occurrences, followed by New South Wales and Victoria. More than half of occurrences in the Northern Territory occurred at sea, and Tasmania and Victoria had about 75 and 70 percent of occurrences while at berth or within harbours.
The most common time period for marine occurrences was between 8 am and 11 am, however, another slight rise in occurrences is observed between 1am and 7 am.
Most occurrences involved one vessel, however there were 43 occurrences where 2 vessels were involved, and one 3-vessel occurrence between a barge in tow with a tug and an offshore support vessel in 2010. The number of occurrences involving Australian vessels has decreased over the time period, and a slight increase was observed for occurrences involving foreign registered vessels.
The main vessels involved were bulk carriers and cargo vessels, which also had the highest number of injuries recorded, and close to one in four reported occurrences resulting in serious or fatal injuries. Typical injuries sustained were falls from height, being hit from falling or swinging objects, and burns from explosions, flame bursts or hot fuel oil.
The most common type of occurrence involved damage to the ship or equipment followed by serious injury and equipment failure. Equipment failure, fires and explosions were associated with the highest number of fatal and serious injuries. Cargo vessels, bulk carriers and tankers were the most common vessels involved in pollution occurrences, making up 22 out of 25 vessels with this occurrence type. The majority of pollution occurrences involved the venting of gases into the atmosphere, or small amounts of dangerous goods or oil leaking.
Since 1984, the Australian Transport Safety Bureau and the former Bureau of Air Safety Investigation have produced numerous aviation research and education reports. This brochure lists those reports in chronological order and arranged by the broad topic area. All reports are available electronically on the ATSB internet site.
Weather-related general aviation accidents remain one of the most significant causes for concern in aviation safety; the often-fatal outcomes of these accidents are usually all the more tragic because they are avoidable.
In the 5 years 2006–2010, there were 72 occurrences of visual flight rules (VFR) pilots flying in instrument meteorological conditions (IMC) reported to the ATSB. Seven of these resulted in fatal accidents, causing 14 fatalities. That is, about one in ten VFR into IMC events result in a fatal outcome.
Flying into IMC can occur in any phase of flight. However, a 2005 ATSB research publication General Aviation Pilot Behaviours in the Face of Adverse Weather concluded that the chances of a VFR into IMC encounter increased as the flight progressed, with the maximum chance occurring during the final 20 per cent of the flight distance.
The dangers of flying VFR into IMC have been recognised for a long time, yet VFR pilots still fly into deteriorating weather and IMC. This publication describes recent weather-related general aviation accidents and incidents that show that weather alone is never the only factor affecting pilot decisions that result in inadvertent IMC encounters. It has been produced solely with the intention of encouraging all pilots, no matter what their experience level, to develop the knowledge and skills required to avoid unintentional operations in IMC.
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.
Key messages
Avoiding deteriorating weather or IMC requires thorough pre-flight planning, having alternate plans in case of an unexpected deterioration in the weather, and making timely decisions to turn back or divert.
Pressing on into IMC conditions with no instrument rating carries a significant risk of severe spatial disorientation due to powerful and misleading orientation sensations in the absence of visual cues. Disorientation can affect any pilot, no matter what their level of experience.
VFR pilots are encouraged to use a ‘personal minimums’ checklist to help control and manage flight risks through identifying risk factors that include marginal weather conditions.
Conclusion
It should be noted that pilot decision making, particularly weather-related decision making, is complex and there is no single solution to the problem of VFR into IMC occurrences. However, there are a number of measures which can be used to reduce the significant risk inherent in the operation of VFR into IMC.
The ATSB Report Improving the odds: Trends in fatal and non-fatal accidents in private flying operations, found that problems with pilots’ assessing and planning were contributing factors in about half of all fatal accidents in private operations. The report encourages all pilots to consider the following strategies to ‘improve the odds’:
make decisions before the flight
continually assess the flight conditions (particularly weather conditions)
evaluate the effectiveness of their plans
set personal minimums
assess their fitness to fly
set passenger expectations by making safety the primary goal
seek local knowledge of the route and destination as part of their pre-flight planning.
Also, becoming familiar with the aircraft’s systems, controls and limitations may alleviate poor aircraft handling during non-normal flight conditions. Finally, pilots need to be vigilant about following rules and regulations that are in place — they are there to prevent errors being made before and during flight. Violating these regulations only removes these ‘safety buffers’.
The Civil Aviation Safety Authority has produced media discs to address weather-related decision making. Weatherwise is an interactive presentation to enhance the ability of pilots to identify hazardous weather conditions. The Weather to Fly disc features interviews with senior pilots and human factors experts, and in-flight footage of specific locations. Some of the points covered are:
pre-flight preparation is important to obtain all the available weather information and update it regularly
make decisions early — when in doubt, turn about
VFR into IMC usually occurs in the last half of the flight
above all, do not close the back or side door (i.e. always leave an ‘out’)
talk to Air Traffic Control if possible
slow the aircraft down in precautionary mode to give more time and reduce the radius of turn
experience of marginal weather with an instructor is valuable
The ATSB often receives reports from pilots that another aircraft is flying too close to them in uncontrolled airspace. Not surprisingly, three quarters of these reports involve aircraft within 10 NM from a non-towered aerodrome.
It is difficult for pilots to spot another aircraft through visual observations alone.
There are twice as many near-collision notifications where pilots had no prior warning of other aircraft in their vicinity, compared with situations when a pilot received an alert by radio, or via traffic avoidance system like TCAS. Supplementing your visual lookout with radio and TCAS information will increase your chance of detecting other aircraft before it's too late. This is known as alerted see-and-avoid. Insufficient communications between aircraft is the most common cause of safety incidents near non-towered aerodromes.
Minimise your risk
The aim at all times is to achieve radio-alerted see-and-avoid, to be aware of other traffic, and position your aircraft appropriately to prevent conflicts with that traffic. Observing these simple points will help to you to do this.
Maintain a lookout for other aircraft at all times.
Get a radio, and always make the standard broadcasts - even when you think there is no nearby traffic.
Check that your radio is
on the correct frequency (get into the habit of listening out for the beepback)
can be heard (momentarily disable the squelch when setting up the radio to check that the volume is set and the headset is connected)
is transmitting (monitor your radio if it has a transmit indication, or do a radio check with someone nearby.
Achieve radio alerted see-and-avoid by making all of the standard broadcasts within 10 NM of a non-towered aerodrome.
Use the same procedures at all non-towered aerodromes, unless otherwise stated in the En Route Supplement Australia (ERSA).
Be aware that any radio-equipped aircraft could be conducting straight-in approaches at non-towered aerodromes
Avoid overflying aerodromes where possible, and take note of IFR inbound and outbound routes.
Early knowledge is the most effective way to stay clear of other aircraft. This works best if you use all your systems to tell others where you are.
Partial engine power loss is when the engine provides less power than commanded by the pilot, but more power than idle thrust.
This kind of power loss is more complex than a complete failure, and it can be much harder to stay ahead of the aircraft. The pilot is thrust into a situation where the engine is still providing some power; however, the power may be unreliable, and the reliability may be difficult to assess. As a result, pilots are uncertain about the capabilities of their aircraft, and what their options are-a situation that has led to loss of aircraft control at heights close to the ground, and fatal outcomes.
And because it's not a substantial part of flight training, pilots tend not to think about it beforehand. Compared to the scenario of total power loss after take-off, they don't think about how they would react in such a scenario. As a result, when it does happen, it can turn into disaster very easily.
How to manage partial power loss after take-off in a single-engine aircraft
1. Plan
Acknowledging the possibility and establishing different strategies to deal with a partial power loss before flight will give you an advantage. By planning your response ahead of time, you reduce your mental workload, mitigate some effects of decision making under stress, and give yourself the confidence to carry out positive actions in the emergency situation.
2. Check your aircraft before you take off
Many partial power loss incidents occurring after take-off could have been identified and prevented during pre-flight checks. Aircraft physical inspection, engine run ups and on take-off engine checks can significantly help prevent partial power loss occurring. Many instances of partial power loss have been found to be fuel and spark plug related, which can exhibit physical symptoms such as:
an rpm drop higher than the maximum prescribed by the manufacturer during run-up checks;
a lower than minimum static rpm on application of full power on take-off;
the engine not 'sounding' or 'feeling' normal, such as general rough running during the take-off run.
3. Maintain control of your aircraft
If you still experience a partial power loss you need to respond immediately. Taking no action is not an option. The first priority is to maintain control. Pilot actions have included turning back to the aerodrome or conducting an immediate forced landing on or off the aerodrome; however, the height of failure, wind speed and direction, traffic and terrain are all factors which will influence this pre-planned option. Maintaining glide speed and no more than a moderate bank angle will ensure you maintain control. Arriving at the ground with wings level and with the aircraft level with terrain, rather than after a stall and or spin can make all the difference.
General Aviation pilots (particularly agricultural pilots) continue to strike wires, such as powerlines, while flying.
Over the past 10 years, there were around 180 wirestrike accidents in Australia. In the majority of these accidents the pilots were aware of the powerlines before they struck them.
Minimise your risk
The following strategies will help minimise the risk of striking wires while flying:
Ensure you are physically and mentally fit to fly. Fatigue can adversely affect short-term memory, reaction time, alertness levels and your focus of attention.
Set client expectations so that they are clear that safety comes first. This includes managing operational pressures, and not accepting tasks that are beyond your personal minimums.
Conduct an aerial reconnaissance before low-flying operations. While a detailed map and a thorough briefing are important, you need to confirm wire locations and other hazards for yourself.
Reassess the risks when plans change. Treat any changes in your plan as a 'red flag' - something you should consider and assess before going any further.
void unnecessary distractions and refocussing when distracted. Distraction, combined with the difficulty in seeing a wire, makes wires extremely hard to avoid at the last minute.
Keep vigilance limitations in mind. The amount of time spent on a monotonous task will affect your ability to remain attentive.
Actively look for wires. Without attention, there is no perception. You are unlikely to notice an approaching wire if you are not actively looking for it, even if you were previously aware of it.
More information
The ATSB has released, in association with the Aerial Agriculture Association of Australia, a booklet that highlights recent wirestrike accidents, and the lessons learnt from them. It also highlights the role of landholders and utility owners in contributing to safety. This includes installing markers on wires, particularly where regular low-level flying takes place.
The Aerial Agriculture Association of Australia and other organisations conduct training in wirestrikes risk management. Further information is available at www.aerialag.com.au(Opens in a new tab/window)
This ATSB booklet aims to increase awareness among flying instructors and pilots of the issues relating to partial power loss after take-off in single-engine aircraft. Accident investigations have shown that a significant number of occurrences result in fatalities or serious injury due to the aircraft stalling and subsequent loss of control resulting in a collision with the ground or water.
Historically, the simulated total loss of power and subsequent practice forced landing has been the core of a pilot’s emergency training. The data, however, shows that during and after take-off, a partial power loss is three times more likely in today’s light single-engine aircraft than a complete engine failure. Furthermore, there have been nine fatal accidents from 2000 to 2010 as a result of a response to a partial power loss compared with no fatal accidents where the engine failed completely.
While one reason for the disparity in these statistics could be the more challenging nature of partial power loss, due to the choices confronting a pilot and the decisions that have to be made immediately, it does not fully explain the different outcomes. Another possible factor is training. Total engine failure after take-off is part of the Day VFR syllabus and is taught and practiced throughout a pilot’s initial training. However, partial power loss after take-off is not a specific syllabus item, and probably does not receive the same emphasis during training.
While acknowledging the difficulty of attempting to train pilots for a partial power loss event which has an almost infinite variability of residual power and reliability, analysis of the occurrences supports the need to raise greater awareness of the hazards associated with partial power loss and to better train pilots for this eventuality.
Partial engine power loss is more complex and more frequent than a complete engine power loss.
Key messages
Most fatal and serious injury accidents resulting from partial power loss after take-off are avoidable. This booklet will show that you can prevent or significantly minimise the risk of bodily harm following a partial or complete engine power loss after take-off by using the strategies below:
pre-flight decision making and planning for emergencies and abnormal situations for the particular aerodrome
conducting a thorough pre-flight and engine ground run to reduce the risk of a partial power loss occurring
taking positive action and maintaining aircraft control either when turning back to the aerodrome or conducting a forced landing until on the ground, while being aware of flare energy and aircraft stall speeds.
Summary
Pre-flight checks prevent partial power loss
ATSB occurrence statistics indicate that many partial power losses could have been prevented by thorough pre-flight checks. Some conditions reported as causing partial power loss after take-off are fuel starvation, spark plug fouling, carburettor icing and pre-ignition conditions. In many cases, these conditions may have been identified throughout the pre-take-off and on-take-off check phases of the flight sequence.
Pre-flight planning and pre-take-off briefings
Even if a partial power loss does occur after take-off, considering actions to take following a partial power loss after take-off during the process of planning and the pre-flight safety brief gives pilots a much better chance of maintaining control of the aircraft, and helps the pilot respond immediately and stay ahead of the aircraft. Considerations include planning for rejecting a take-off, landing immediately within the aerodrome, landing beyond the aerodrome, and conducting a turnback towards the aerodrome.
Stay in control
If nothing else, maintain glide speed and plan a maximum bank angle against your personal minimums, which you will not exceed if a turnback is an option. Be prepared to re-assess the situation throughout any manoeuvre.
Wirestrikes pose an on-going problem to aerial agricultural operations. There are 180 wirestrike accidents in the Australian Transport Safety Bureau (ATSB) database for the period between 2001 and 2010. Of these, 100 involved agricultural flying. Research by the ATSB has shown that 63 per cent of pilots were aware of the position of the wire before they struck it.
This publication describes recent aerial agricultural wirestrike accidents. In all these cases, the aircraft struck a powerline that was known to the pilot. In many of these accidents, the pilot was not completely focused on the immediate task of flying due to a change in plans.
This publication also explains a number of strategies developed by the Aerial Agriculture Association of Australia (AAAA) and the ATSB to help agricultural pilots manage the on-going risk of wirestrikes during spraying operations. These include:
ensure you are physically and mentally fit to fly
set client expectations so that they are clear that safety comes first
conduct a thorough briefing and study a detailed map of the area before the flight
conduct an aerial reconnaissance before spraying and conduct an extra aerial reconnaissance before the clean-up run
reassess the risks when plans change
avoid unnecessary distractions and refocus when distracted
be aware of vigilance limitations
don’t rely on your ability to react in time to avoid a wire
actively look for and remind yourself of wires
be aware of and manage pressures
have a systematic approach to safely managing wires.
A number of changes have been made to this document since it was first published in May 2011. The number of occurrences reported have remained the same, and only the rates of occurrences per departure or hours flown have changed. See page vi of AR-2011-020 for further details.
In 2010, uncontained engine failures occurred on two high-capacity aircraft (a Boeing 747 and an Airbus A380); two air transport aircraft almost collided in non-controlled airspace, coming within 40 metres of each other; and a cockpit window blew out of a Metro aircraft at about 20,000 feet, resulting in a rapid cabin decompression. These are some of the occurrences described in a new report on occurrence data for the period 2001 to 2010. The Australian Transport Safety Bureau (ATSB) has tabled a list of frequently occurring events and presents them in this report along with trends over time.
During 2010, the top five most frequently occurring events for air transport relating to accidents and serious incidents were aircraft separation, aircraft control, powerplant and propulsions systems, miscellaneous events and terrain collisions, runway events and ground operations. For air transport incidents they were wildlife strikes, failure to comply, mechanical systems, miscellaneous and airframe events. For general aviation aircraft involved in accidents and serious incidents, the top five most frequently occurring events were terrain collisions, aircraft control, powerplant and propulsion, aircraft separation and runway events. Where general aviation aircraft were involved in an incident, the top five most frequently occurring events were airspace incursion, failure to comply, wildlife strikes, runway events and aircraft separation.
General aviation operations continue to have a fatal accident rate per million departures that is about 4.3 times higher than for air transport. The general aviation accident rate per million departures is about three times higher than air transport. No fatal accidents were recorded in high-capacity air transport between 2001 and 2010. During 2010, there was one fatal accident in low-capacity air transport, and charter operations recorded no fatal accidents. Between 2001 and 2010, most fatal accidents in air transport were in charter operations. Charter aeroplanes and helicopters have a similar accident and fatal accident rate. In air transport, charter operations offer the best potential target for safety improvement.
In general aviation, there were 147 fatal accidents and 236 people killed between 2001 and 2010. The general aviation accident and fatality rate is not evenly dispersed across all sub-groups or types of aircraft. Of all general aviation sub-groups, private/business flying has the highest fatal accident rate and the greatest number of fatalities (135 people between 2001 and 2010). Agriculture has the highest accident rate and second highest fatal accident rate. This is followed by mustering, survey and photography, and flying training. In aerial work, helicopters have a higher accident and fatal accident rate than aeroplanes. In contrast to this, flying training and private operations helicopters have a higher accident rate than aeroplanes, but overall, are associated with a smaller number of total fatalities.
