Living Near Zero – New Challenges for Air Safety

Living Near Zero – New Challenges for Air Safety

Between 17 July 2014 and 24 July 2014 the aviation industry has been rocked by three loses of commercial passenger aircraft and 462 lives:

In this article we will separate deliberate violent/terrorist/military actions from ‘accidents’.  However, the MH17 loss certainly raises questions about operational route planning, regulation, risk assessment and the value of defensive aids. The International Civil Aviation Organisation (ICAO) will be hosting a special high-level meeting on 29 July 204 with the Directors General of the International Air Transport Association (IATA), Airports Council International (ACI) and the Civil Air Navigation Services Organisation (CANSO). The subject is how to “more effectively mitigate potential risks to civil aviation arising from conflict zones”.

Harro Ranter of the Aviation Safety Network has analysed the losses in 2014 to date and July 2014 in particular and produced a historic comparison. Statistically it is not unusual for clustering of accidents, as discussed in a recent BBC article.  While no consolations to the bereaved families of the victims of these recent events, with an estimated 36 million commercial flights per annum worldwide, the risk of dying in a commercial airline accident remains remarkably remote. Nearly 20 years ago years ago there was alarm that unless commercial airliner safety improved we would be averaging a airliner accident every week globally, as air traffic increased.  Flight International correspondent David Learmount recently looked back at the 1970s and in particular the first half of 1974.  He found:

…that there had been 25 fatal accidents involving passenger flights in that period…

So we’d been at the weekly accident stage before! Of course the 1990s safety performance was itself a product of two decades of hard work reducing the accident rate faster than the increase in total traffic.  The fear two decades ago was that traffic would outpace our ability to improve.  This triggered a number of safety initiatives (such as the Commercial Air Safety Team, [CAST]), which coupled with increasing understanding of organisational accidents and the introduction of more modern aircraft have allowed improvements to continue.  Aerossurance recently discussed data from Airbus that illustrates the improvements with newer technology aircraft.  Aerossurance also recently highlighted positive performance in the European Union discussed in the European Aviation Safety Agency’Annual Safety Review. For the first half of 2014, Learmount  points out:

…a preliminary estimate of airline fatal accidents in the first six months of 2014 shows six, and the total number of resultant deaths is 267.

But those numbers for the first half of 2014 include the missing Malaysia Airlines Boeing 777-200ER flight MH370, which may turn out to have been due to criminal acts and 4 accidents which did not involve passengers.  In fact, there was just one confirmed fatal accident with passengers, a Nepal Airlines Viking DHC-6 Twin Otter, which flew into a mountain side in poor visibility killing 18 people (see the Aviation Safety Network database entry here and footage of the accident site here).

Bottom line: that’s at most just 2 fatal commercial airliner passenger accidents worldwide in the first 6 months of 2014 and a total of at most 4 this year to date, out of around 20 million flights.

While this rarity of accidents is good news, it does emphasise new challenges for aviation safety professionals.  One challenge is to avoid being fixated only on learning the lessons of the ‘last big accident’, as when accidents are rare, the most recent accidents are less likely to be a true reflection of on-going risk.  Equally there is a significant risk of complacency (i.e. ‘well that accident would never have happened to us…’). As Michel Masson of EASA recently commented:

Very few fatal accidents means:

    • Unclear trend and correlation between accident scenarios,
    • Risk of complacency and of “safety awareness erosion”,
    • Learning from accidents is insufficient: a risk-based approach making use of precursors is needed.

This means the industry needs to increasingly pay more attention to more minor incidents and failures of individual safety controls or barriers which give a better indication of on-going risk. As Aerossurance discussed recently the European Central Repository of occurrences is growing at around 90,000 reports per annum.  That attention needs to include:

  • applying investigative expertise and rigour previously reserved for more serious events
  • constantly revaluating assumptions on barrier/control effectiveness that underpin risk assessments
  • sharing experience between organisations and routinely challenges if that ‘could happen here’

This is also one reason that moves are afoot to develop standardised Flight Data Monitoring indicators (e.g. EASA / UK CAA). Masson goes on to explain:

The European Commercial Aviation Safety Team (ECAST) therefore took the following orientations back in 2012:

    • Severe incidents must be investigated and the reports published and shared among the community – in Europe, this poses a translation challenge;
    • Safety assumptions, safety defences or barriers must be continuously challenged using selected incidents through a formal process,
    • An efficient dissemination process must be established.

For more on the ECAST Methodology to Assess Future Risks click here. Forums do exist for operators to discuss experience from incidents.  The UK Flight Safety Committee (UKFSC), formed 55 years ago on 29th July 1959.  UKFSC has grown from 9 members in 1959 to around 100 today, from the UK and overseas.  Airlines share occurrence details under the Chatham House Rule.  No doubt this approach will need to become more widespread.

UPDATE 19 February 2016: We look at some of the challenges analysing helicopter accident rates: US Helicopter Accident Rate Analysis

UPDATE 20 April 2016: See also our article: NASA ASRS at 40 and the Continued Challenge of Timeliness

UPDATE 1 August 2016: Flight International look at safety performance in 2015: Air travel is safer than ever, but safety today is not all about accidents.  They note:

The problem for statisticians in an era of ever-reducing accident numbers is that serious accidents are now so rare that the statistics only become useful when taken over a long period of time. A decade is now about the shortest period that can be considered a reliable indicator of trends, but comparisons over longer periods have their limitations, too. The relentless advance of engine and airframe engineering quality and of avionic/navigation technology have been the major drivers of airline safety improvement since the Second World War, so accidents that happen with today’s technology tend to have different causes than those in the past.

Paul Hayes, of Flight Ascend says comparisons of current and historic accidents rates can be like comparing apples with oranges: “The numbers are distorted by things that don’t happen anymore.”  he advocates using rolling averages and lengthening the period.

UPDATE 7 August 2016: UK air traffic service provider NATS explain how they have achieved:

…historically low…occurrence rates…by focusing …towards and eliminating failures…

[However]..we are running out of incidents to count and the remaining incidents that are left tend to be random, so they are not representative of the operation. These events are unlikely to occur again and any mitigation we identify…is unlikely to be effective and could even make the system less safe, as it is over burdened with workaround procedures and becomes too brittle and inflexible.

This situation is also likely to get more tricky to work with in future. So, if we are to continue to improve our safety performance we need a complementary alternative …focusing on making as many things as possible go right…

NATS use the term Safety 1 and Safety 2, a concept promoted by Eurocontrol (From Safety-I to Safety-II: A White Paper).

Although sometimes we do find the associated dogma from Safety-I to Safety-II theorists unhelpful, as Aerossurance’s Andy Evans has previously commented “Safety-I is minimising the bad and Safety-II is maximising the good”, which is surely a positive enhancement.

UPDATE: 28 August 2016: We look at an EU research project that recently investigated the concepts of organisational safety intelligence (the safety information available) and executive safety wisdom (in using that to make safety decisions) by interviewing 16 senior industry executives:  Safety Intelligence & Safety Wisdom.  They defined these as:

Safety Intelligence the various sources of quantitative information an organisation may use to identify and assess various threats.

Safety Wisdom the judgement and decision-making of those in senior positions who must decide what to do to remain safe, and how they also use quantitative and qualitative information to support those decisions.

UPDATE 28 December 2016: In A Dangerous World, U.S. Commercial Aviation Is On A Remarkable Safety Streak:  This article reports an accident rate of US Part 121 carriers of 1.55 per million flying hours.

Over the past two decades lowering accident and fatality rates has been almost entirely the result of paying ever-greater attention to ever more minute factors…

Commercial aviation seems to have:

…reached a state of business maturity in which carriers no longer operate from year-to-year with the possibility of bankruptcy hanging over heads of many carriers, also has reached a state of safety maturity. Near-absolute safety now is the expected and assumed norm.

The last fatal part 121 accident was the Colgan accident on 12 Feb 2009.  Ominously however:

A cynic would argue that all this rather impressive data leads only to one rather gruesome conclusion: we’re due for a big, deadly crash any time now.

Aerossurance has extensive experience in aviation safety management and safety analysis.  For safety advice you can trust, contact us at