This report was updated on 23 October 2014 with revised hours flown data used for the calculation of occurrence rates by aircraft type.

 Why did we do this research

This study has been undertaken in order to further understanding of the nature and impact of fumes and smoke related occurrences in relation to the safety of aircraft operations in Australia and, in doing so, evaluate associated data availability and suitability. This report also addresses recommendations from a 2011 report commissioned by the Civil Aviation Safety Authority (CASA) by an Expert Panel on Aircraft Air Quality that aviation safety agencies work together to provide a comprehensive study of cabin air contamination incidents.

The study was undertaken in two parts; the first involved an in-depth analysis of aviation safety data sets held by the Australian Transport Safety Bureau (ATSB), CASA and the Department of Defence for the 2008-2012 period. The second part of the study involved a basic risk analysis of smoke/fumes safety events using the bowtie risk model.

What the research found

There were over 1,000 fumes/smoke events reported to both the ATSB and CASA over the 5-year period. From a flight safety perspective, most were found to be minor in consequence. There was a single flight crew incapacitation event and a further 11 minor injury events to crew. In the higher risk occurrences, precautionary defences (most commonly diversions) were found to be effective in avoiding escalation of the event.

The British Aerospace BAe 146 was the aircraft type most commonly involved in fumes/smoke events when taking into account flying activity. The Airbus A380, Boeing 767, Embraer EMB-120 and E-190 were among other aircraft types that also had a higher-than-average rate of fumes/smoke occurrences over the period.

The most common source of fumes/smoke was aircraft systems issues, primarily relating to failure or malfunction of electrical and auxiliary power unit (APU) systems. Equipment and furnishings also featured highly as a source of fumes and smoke. Within this category, air conditioning and galley equipment were the most common sources of fumes/smoke. External sources of fumes/smoke and cargo/baggage related events were relatively rare.

The matching of CASA and ATSB data records provided valuable information on the issue of fumes/smoke which enabled visibility of occurrences from both an engineering and operational perspective. However, many reports of fumes/smoke events contained insufficient detail for coding of the source or affected components.

Safety message

Fume and smoke events are generally appropriately managed by flight and cabin crew resulting in little consequence. Good reporting by aircraft operators, with sufficient detail, to both the ATSB and CASA where relevant will assist ongoing efforts to monitor the risk of fume and smoke events.

The Aviation Short Investigation Bulletin covers a range of the ATSB’s short investigations and highlights valuable safety lessons for pilots, operators and safety managers.

Released periodically, the Bulletin provides a summary of the less-complex factual investigation reports conducted by the ATSB. The results, based on information supplied by organisations or individuals involved in the occurrence, detail the facts behind the event, as well as any safety actions undertaken. The Bulletin also highlights important Safety Messages for the broader aviation community, drawing on earlier ATSB investigations and research.

Issue 28 of the Bulletin features 11 safety investigations:

Jet aircraft

• Turbulence event involving a Boeing 777, VH-VPE

Turboprop aircraft

• Runway excursion involving a Fairchild SA226, VH-OGX

Piston aircraft

• Hard landing involving a Grob G 115C2, VH-ZIV
• Take off event involving a De Havilland DH-82 Tiger Moth, VH-RAY
• Loss of control involving a Piper PA-28R 201, VH-HVX
• Pilot incapacitation involving a Piper PA 28-180, VH-PXB
• Aircraft proximity event between a Cessna 172S, VH-FPV, and a Piper PA 28-161, VH-OWO
• Near collision between a Piper PA-25, VH-MLS, and an AMS-flight DG-303, VH-DGA

Helicopters

• Loss of separation between a Schweizer 269C, VH-HYD and a Piper PA-31, VH-IBI
• Engine failure involving a Eurocopter EC120B, VH-JYV
• Controlled flight into terrain involving a Robinson R22, VH-LZR

The Aviation Short Investigation Bulletin covers a range of the ATSB’s short investigations and highlights valuable safety lessons for pilots, operators and safety managers.

Released periodically, the Bulletin provides a summary of the less-complex factual investigation reports conducted by the ATSB. The results, based on information supplied by organisations or individuals involved in the occurrence, detail the facts behind the event, as well as any safety actions undertaken. The Bulletin also highlights important Safety Messages for the broader aviation community, drawing on earlier ATSB investigations and research.

Issue 27 of the Bulletin features 11 safety investigations:

Turboprop aircraft

• Aircraft separation issue involving an Ayres S2R, VH-WBK and an unmanned aerial vehicle
• Ground proximity event between Dornier DO228, VH-VJN and a vehicle
• Loss of ground control involving Air Tractor AT-502B, VH-FLH
• Ground proximity event involving a Cessna 208, VH-LNI and a vehicle

Piston aircraft

• Total power loss involving a Piper PA-28 161, VH-CCQ
• Incorrect configuration involving Beech A36, VH-YEN
• Hard landing involving a Rolladen-Schneider Flugzeugbau LS7-WL, VH-XJJ
• Hard landing involving a Cessna U206G, VH-UFT
• Collision with terrain involving a Grumman G 164A, VH-CCF
• Aircraft proximity event between a Piper PA-34, VH-FOE and a Piper PA-39, VH-MAB

Helicopters

• Wirestrike involving a Robinson R44, VH-HJT

What is turbulence?

High in the sky, as you are cruising to your destination, the seat belt sign goes on. As you look out the window, there are no clouds for kilometres. What could you possibly run into at this height? Turbulence – a frequently invisible problem for aircraft.

Turbulence is a weather phenomenon responsible for the abrupt sideways and vertical jolts that passengers often experience during flights, and is the leading cause of in-flight injuries to passengers and cabin crew.

Turbulence is caused by the irregular movement of air, and often cannot be seen. When air masses with different speeds, direction or temperatures meet each other – such as a warm or cold front, a thunderstorm, air flowing over or around mountains, or near jet streams – turbulence is likely to occur.

How serious is turbulence?

While turbulence is normal and occurs frequently, it can be dangerous. Turbulence by its nature is unpredictable – occurring without warning, and ranging from a few minor bumps to a major shake-up. Aircraft can handle even severe turbulence, and are designed to flex with the bumps and jolts. Turbulence is usually more severe in the cabin than in the cockpit.

Turbulence is rarely a threat to passenger aircraft or to pilot control of the aircraft.

So why do you need to be prepared for turbulence? While your aircraft is designed to take turbulence, your body is not.

In a typical turbulence incident, 99 per cent of people on board receive no injuries.  However, the bumpy ride can cause passengers and cabin crew who are not wearing their seat belts to be thrown around without warning. About 25 in-flight turbulence injuries are reported in Australia each year to the Australian Transport Safety Bureau (ATSB), and many more go unreported. Some of these injuries are serious, and have resulted in broken bones and head injuries.

An ATSB report found that passengers being thrown up and out of their seat during turbulence was the second most common type of head injury on aircraft.

For the five-year period 2009 to 2013, there 677 turbulence occurrences on flights in, to or from Australia that were reported to the ATSB, with 197 minor injuries and 2 serious injuries to passengers and cabin crew. The United States Federal Aviation Administration (FAA) estimates that the cost to the worldwide aviation industry of turbulence injuries is over US$100 million annually, and growing.

If you travel by air, you need to take turbulence seriously.

The Aviation Short Investigation Bulletin covers a range of the ATSB’s short investigations and highlights valuable safety lessons for pilots, operators and safety managers.

Released periodically, the Bulletin provides a summary of the less-complex factual investigation reports conducted by the ATSB. The results, based on information supplied by organisations or individuals involved in the occurrence, detail the facts behind the event, as well as any safety actions undertaken. The Bulletin also highlights important Safety Messages for the broader aviation community, drawing on earlier ATSB investigations and research.

Issue 26 of the Bulletin features 9 safety investigations:

Jet aircraft

• Loss of separation assurance between an Airbus A320, VH-VNQ and Boeing 737, VH-VZB
• Incorrect configuration involving Airbus A320, VH-FNP
• Flight planning related event involving an Airbus A330, VH-QPD
• Turbulence event involving a Boeing 767, VH-OGU

Turboprop aircraft

• Fuel related event involving a Fairchild SA227, VH-UUO

Piston aircraft

• Electrical system event involving a Cirrus SR22T, VH-LBQ
• Aircraft proximity event between a Piper PA-44, VH-CZH and a Mooney M20, VH-DJU

Helicopters

• Loss of control involving a Eurocopter EC-120B, VH-VMT
• Aircraft proximity event between a Bell 206, VH-WCS and a PZL Bielsko 51, VH-XOP

The Aviation Short Investigation Bulletin covers a range of the ATSB’s short investigations and highlights valuable safety lessons for pilots, operators and safety managers.

Released periodically, the Bulletin provides a summary of the less-complex factual investigation reports conducted by the ATSB. The results, based on information supplied by organisations or individuals involved in the occurrence, detail the facts behind the event, as well as any safety actions undertaken. The Bulletin also highlights important Safety Messages for the broader aviation community, drawing on earlier ATSB investigations and research.

Issue 25 of the Bulletin features 10 safety investigations:

 Turboprop aircraft

• Runway event involving a Beech 1900C, VH-­VNV
• Runway incursion between a Fairchild SA227, VH-­UZP and a Bell 47G, VH-­UTF

Piston aircraft

• Pilot incapacitation event involving a Cessna 210, VH-JMG
• Aircraft proximity event between a Cessna 172, VH-­NUU and a Beech F33A, VH­-ZBZ
• Wheels-up landing involving a Beech 95­B55, VH­-TLP
• Runway undershoot involving a Cessna 404, VH­-HAZ
• Loss of control involving a Cessna 172, VH-IGS
• Mid-air collision involving a Cessna 152, VH-­TNV and a Jabiru J160, 19­4430

Helicopters

• Collision with terrain involving a Robinson R44, VH­-UGC
• Total power loss involving a Robinson R22, VH-­STK

The Aviation Short Investigation Bulletin covers a range of the ATSB’s short investigations and highlights valuable safety lessons for pilots, operators and safety managers.

Released periodically, the Bulletin provides a summary of the less-complex factual investigation reports conducted by the ATSB. The results, based on information supplied by organisations or individuals involved in the occurrence, detail the facts behind the event, as well as any safety actions undertaken. The Bulletin also highlights important Safety Messages for the broader aviation community, drawing on earlier ATSB investigations and research.

Issue 24 of the Bulletin features 15 safety investigations:

Jet aircraft

• Runway event involving a Fokker F28, VH-JFB
• Ground proximity event between a Boeing 737, VH-VZA and a security vehicle

Turboprop aircraft

• Wheels up landing involving a Cessna 441, VH-SMO
• Airspace related event involving a Saab 340B, VH-ZLJ and parachutists
• Wirestrike involving an Air Tractor AT 502, VH-CJY

Piston aircraft

• Landing on a closed runway involving a Cessna 404, VH-HVR
• Fuel starvation event involving a Beech BE58, VH-ECL
• Loss of control involving a Piper PA 28R-200, VH-MMU
• Engine fire involving a Beech A36, VH-FFY
• Runway incursion involving a De Havilland DH 82, VH-BJE and a Piper PA 34, VH-SEN
• Runway incursion between a Cessna 206, VH -LHX and a Cessna 210, VH-HGZ
• Total power loss involving a Piper PA 28 140, VH-RVJ

Helicopters

• Partial power loss involving a Bell 47G, VH-RTO
• Aircraft proximity event between a Cessna 172, VH-RQZ and an Agusta AW139, VH-ESZ
• Aircraft configuration event involving a Robinson R22, VH-ONT

The Aviation Short Investigation Bulletin covers a range of the ATSB’s short investigations and highlights valuable safety lessons for pilots, operators and safety managers.

Released periodically, the Bulletin provides a summary of the less-complex factual investigation reports conducted by the ATSB. The results, based on information supplied by organisations or individuals involved in the occurrence, detail the facts behind the event, as well as any safety actions undertaken. The Bulletin also highlights important Safety Messages for the broader aviation community, drawing on earlier ATSB investigations and research.

Issue 23 of the Bulletin features 13 safety investigations:

Jet aircraft

• Abnormal engine indications involving a Boeing 747-438, VH-OJS
• Weather related event involving a Boeing 737, VH-YFF
• Departure from an incorrect intersection involving an Embraer ERJ 190, VH-ZPC
• Two turbulence events involving a Boeing 737, VH-VZY and a Bombardier DHC-8-402, VH-QOP
• Loss of separation between an Airbus A320, VH-VFJ and a Bell 412, VH-VAO

Turboprop aircraft

• TCAS event between an ATR72, VH-FVH and a Bombardier DHC-8-315, VH-TQZ
• Turbulence encounter involving a Bombardier DHC-8-402, VH-QOD

Piston aircraft

• Wheels up landing involving a Cessna 210, VH-ZMT
• Collision on the ground involving a Cessna 172R, VH-IMS

Helicopters

• Power loss involving a Robinson R44, VH-ZON
• Total power loss involving a Bell 47G2A, VH-KHJ
• Hard landing involving a Bell 206B, VH-EPQ
• Loss of control involving a Robinson R22, VH-EGN

Why have we done this report

Thousands of safety occurrences involving Australian-registered and foreign aircraft are reported to the ATSB every year by individuals and organisations in Australia’s aviation industry, and by the public. The aim of the ATSB’s statistical report series is to give information back to pilots, operators, regulators, and other aviation industry participants on what accidents and incidents have happened, how often they are happening, and what we can learn from them.

What the ATSB found

In 2012, there were 107 accidents, 195 serious incidents, and over 7,300 incidents reported to the ATSB involving Australian (VH– registered) aircraft, and a further 570 occurrences that involved foreign-registered aircraft operating within Australia or its airspace.

Commercial air transport aircraft were involved in the majority of incidents reported each year, and in 2012 the most common safety incidents reported were animal strikes, non-compliance with publish information or air traffic control instructions, and aircraft system and airframe issues. Most accidents and serious incidents related to reduced aircraft separation and engine malfunction.

General aviation aircraft, such as aircraft conducting flying training, aerial work, or private/pleasure flying, were involved in 38 per cent of occurrences reported to the ATSB in 2012. Airspace incursions, compliance with air traffic control, and birdstrikes were the most common incidents reported, with most accidents and serious incidents involving terrain collisions, engine failures, and a loss of aircraft control. Private/business operations had the highest number of fatal accidents in 2012 out of any year in the last 10 years, with 15 fatal accidents resulting in 22 fatalities. In contrast, commercial aerial work operations recorded the lowest number of accidents in the past 10 years.

In most operation types, helicopters had a higher rate of accidents and fatal accidents than aeroplanes.

A new addition to the ATSB’s aviation statistics are data on recreational (non–VH) aircraft safety. In 2012, the majority of the 274 occurrences reported were controlled airspace incursions, engine malfunctions, aircraft control problems, and runway events such as veer-offs.

Over the past 10 years, aerial agriculture had the most accidents and fatal accidents per hour flown, followed by private/business operations. Aerial survey and aerial mustering had the next highest accident and fatal accident rates.

Safety message

Aviation occurrence statistics provide a reminder to everyone involved in the operation of aircraft that accidents, incidents, and injuries happen more often than is widely believed. Some of the most frequent accident types are preventable, particularly in general aviation. Pilots and operators should use the misfortunes of others to help identify the safety risks in their operation that could lead to a similar accident or serious incident.

Timely and thorough reporting of safety incidents is paramount. The ATSB’s capability to understand why accidents and incidents happen and to identify the major safety risks in different types of aviation operations is at its best when all aviation participants report all safety incidents. The information the ATSB provides helps everyone in the aviation industry to better manage their safety risk.

Why the ATSB is doing this research

One of the main objectives of air traffic services (ATS) is to prevent the collision of aircraft. Aircraft separation standards are set to ensure that the chance of a mid-air collision is very remote. When they are infringed, there are fewer defences left to guard against a mid-air collision. This ATSB research investigation looks at loss of separation (LOS) incidents in Australian airspace to understand how often they occur and in what contexts, how and why they are occurring, and whether there are any wider implications that the air traffic system is not functioning appropriately.

What the ATSB found

Although there had been an increase in the number of occurrences reported to the ATSB over the 2 years ending in June 2012, there were fewer LOS occurrences during that period than during 2005 to 2008. Traffic levels have generally increased during the same period. A LOS between aircraft under air traffic control jurisdiction happens on average about once every 3 days. In almost 90 per cent of LOS occurrences, there was no or minimal risk of aircraft colliding. On average, however, there are six occurrences per year where an elevated risk of collision exists. There have been no mid-air collisions in Australia between two aircraft under ATS control.

The investigation found that military controlled terminal area airspace in general, and all airspace around Darwin and Williamtown in particular, had a disproportionate rate of LOS (for civilian aircraft). Most of these LOS occurrences were contributed to by air traffic controller actions. This may be a result of the nature of aircraft operations and airspace constraints at some military airports, leading to reduced use and effectiveness of strategic separation defences, thereby placing more responsibility for separating aircraft directly onto the controllers. Furthermore, as military ATS are not subject to safety oversight by the Civil Aviation Safety Authority (CASA), there is no independent assessment and assurance as to the safety of civilian aircraft operations at military airports.

In civil airspace, LOS occurrences attributable to pilot actions are not monitored as a measure of airspace safety nor actively investigated for insight into possible improvements to air traffic service provision. As about half of all LOS incidents are from pilot actions, not all available information is being fully used to assure the safety of civilian airspace.

What's been done as a result

The ATSB has issued recommendations to the Department of Defence to review all processes and controls in place for aircraft separation in military ATS and to CASA to review whether its current level of involvement with military ATS is sufficient to assure the safety of civil aircraft operations. The ATSB also recommends using all available information, including pilot attributable LOS occurrences, to assure the safety of civilian airspace, and will itself investigate all serious LOS incidents.

Safety message

Aircraft separation is a complex operation with many levels of defences to avoid errors and to safely manage the results of the errors that will inevitably be made from time to time by air traffic controllers and pilots. The defences ensure that even if a LOS does occur, the chance of an aircraft collision is still very remote. Safety could be enhanced through understanding and addressing the reasons for the disproportionate rate of LOS occurrences involving civil aircraft in military airspace, and through the ongoing monitoring and investigation of all LOS incidents in civil airspace.