Bird Strike 2

What makes a bird strike different is that it’s an unpredictable collision. If we talk about aircraft collisions with terrain the outcome is predicable bad. All that kinetic energy must go somewhere. So, a high-speed vehicle hitting something that is immovable is not going to end well.

Now, it must be said that some hunting birds can dive at incredible speeds. More typically, a large bird in flight between feeding sites isn’t going to be traveling fast. In fact, it may as well be viewed as a static object relative to an aircraft in flight. A bird in-flight is unlikely to be able to take avoiding action. For a pilot the action of “see and avoid” may work in respect of other aircraft but a bird ahead is no more than a pinprick in the sky.

These factors make aircraft bird strikes inevitable. That said, the range of outcome because of impacts are rarely at the severe end of the scale. One reason for this is the effort made at design certification to ensure an aircraft is sufficiently robust. Damage can occur but if the aircraft design and test processes have been rigorous everyone should get home safely.

I remember paying particular attention to the zonal analysis done by several major manufacturers. In my experience the most difficult designs are for those of business jets and large helicopters. One of the design challenges in both cases is the limited physical real estate within the aircraft structure. Weight is another big consideration. This leads to cramming essential avionics and electrical systems and their interconnections into confined spaces.

Zonal analysis is about ensuring there’s segregation between different systems. Afterall what’s the point of having two Attitude & Heading Reference Systems (AHRSs)[1] and putting them next to each other in the nose cone of an aircraft. That’s not a good design strategy. One damaging impact must not take out two essential independent aircraft systems.

It’s just as important to ensure an aircraft’s wiring isn’t all bundled togther and taken through one connector. That may save money on electrical parts but it’s not going to work after being hit hard by a 5kg goose.

These issues will need particular care in the new electric vertical take-off and landing (eVTOL) aircraft that are on the drawing boards. Choosing a safe architecture, manufacturers must balance the use of creative design solutions, to produce a competitive product, with limited physical space.

A couple of key words in the certification requirements concern hazards that are anticipated. Bird Strike is hazardous and aircraft systems and equipment must “perform their intended function” should it occur. See EASA Special Condition for small-category VTOL aircraft, Subpart F[2].

POST: Good to see the bird strike criteria Joby’s airworthiness criteria: A blueprint for the nascent eVTOL industry – Vertical Mag



Bird Strikes

I watched two rather aloof Branta canadensis in our local park the other day. They seemed oblivious to all the other birds on the priory pond. I’d certainly describe these two birds as being well fed. Given their stature and size, they looked formidable. These resident North American visitors are not to be messed with and are only eclipsed by the Swans on Reigate’s pond.

This species of bird has adapted well to living in urban and suburban areas and are frequently found on lakes, ponds, and rivers. I used to see large flocks of them gather on the river Thames. That was only a couple of miles from London Heathrow.

Even though they are numerous in the UK these birds are protected by law (Wildlife and Countryside Act 1981[1]). Today, the population numbers may be as high as 62,000 breeding pairs[2]. Although these birds have the capability to fly great distances they tend to hang around where there’s a reliable source of food. Bird populations are changing their behaviours as a result of climate change.

Geese fly in the typical V-formation which is called a “wedge” or skein. From time to time, I see them fly over my house at a few hundred feet as they move between local lakes and ponds. They are easy to spot and often noisy as they elegantly traverse the sky.

Birds and aircraft share the same airspace. This is not a beneficial relationship for either. Strikes occur around the world every day. In the history of aviation, there have been hundreds of aircraft accidents and more than 47 fatal aircraft accidents caused by bird strikes[3].

It must be said that most bird strikes cause little damage to aircraft but that is highly dependent upon the size of the unfortunate bird and their habits. The story can be very different when an impact is with a Canada goose. Their large size and tendency to fly in flocks can have a devastating impact. On 15 January 2009, a US Airways Airbus A320 aircraft[4] ended up in Hudson River as the result of an encounter with such birds.

The risk of collision between birds and aircraft have always been part of aircraft operations. As a result, measures are taken to certify aircraft to be robust in the event of such collisions. Additionally, there’s a great deal of effort made at major airports to keep birds away from active runways.

Most of the bird threat to aviation safety exists when travelling at speed at relatively low altitudes. Bird strikes happen most often during take-off or landing. This makes me think that bird strikes are going to be a regular feature of the operations of Urban Air Mobility (UAM) / Advanced Air Mobility (AAM). The use of use highly automated aircraft may offer the opportunity to provide sophisticated bird avoidance features. However, so far, I’ve detected no talk of such features.

POST 1: A useful safety booklet Large Flocking Birds (

POST 2: A recent Boeing 737-800 serious incident LinkedIn

POST 3: An example of what can happen from 2019 Ural Airlines Flight 178 – Wikipedia

POST 4: Another useful safety booklet Bird strike, a European risk with local specificities, Edition 1 – Germany | SKYbrary Aviation Safety






I am in two minds. When I see the words: “in so far as practicable” I can think; great, a degree of flexibility. On another occasions when I see the self-same words I think; that’s too vague and indistinct. It can easily circumvent more strict language.

Practicable is a perfectly useful word. The idea that it’s practical to do something and likely to succeed can be a matter of reasoned judgement. However, there lies the crux of the problem. It’s the subjective of that judgement, as to what’s practical and will it succeed, that becomes the possible difficulty.

If there’s a clause in a group’s constitution or working arrangements that says: “in so far as practicable” then it can become open season for someone to avoid a commitment or go their own way. That can be to shoot a big hole in a set of agreed expectations.

A lot depends on where the burden of proof sits. In other words, I may assert that something is not practicable but is it then for someone else to prove me wrong? Or do I have to provide the necessary proof?

There are elements of degree here too. If the assumption is that a judgement can be a snap judgement that’s one thing. However, there may be an assumption that a judgment is based on a rigorous level of analysis and reasoning.

The term “in so far as practicable” is most useful when applied thoughtfully and with honest intent. That the person applying this caveat would work hard to undertake whatever obligation was written and only as a fall back, having been unable to meet an obligation, revert to the use of these words.

Context and circumstances weigh heavily on what is practicable. An easy task on a sunny day can be a nightmare in a thunderstorm. Some legal clauses go as far as “insofar as is reasonably practicable in the circumstances”.

I guess I’m coming around to the wish that the “ALARP” concept (short for “as low as reasonably practicable”) would be sparingly used. ALARP weighs risk mitigation, elimination or reduction against time, trouble, and money. That’s a balancing act where there’s no perfect answer.

ALARP is a basic concept in health and safety law, but it hasn’t caught on in aviation or at least safety of flight. It’s not that aviation is blind to the fact that flight safety can be a priority, but it will never receive infinite time, trouble, and money.

It’s more that with flight there’s always a choice. It’s a “go – no go” choice. If adequate risk mitigation, elimination or reduction is not available the reasonable choice is to stay on the ground.


This coming week an international tradeshow takes place in London. It’s easier to get to than it’s ever been, at least for me. The wonderful new Elizabeth line[1] goes directly to the ExCeL London.

The organisers describe the event as for the commercial aviation aftermarket. Personally, I don’t like those terms, but I guess it’s a way of grouping together all the activities that happen after an aircraft has been delivered by an airframe manufacturer. That’s maintenance, repair, overhaul and a good deal of other activities. It might be sophisticated test equipment or spanners. It might be hanger facilities or complete aero engine overhauls.

MRO Europe[2] is a major European event. Along with the exhibition there’s a conference highlighting some of the challenges aviation faces. There are a whole lot of uncertainties that are rippling through the industry. Recovery from the impact of the COVID pandemic is happening but it has taken its toll. 

The conference subject that caught my eye is that concerning the shortage of qualified people. Civil aviation must compete with every other international technology-based industry. Long gone are the days of the 1960s and 70s when aviation was associated with glamour and a kind of post-war kudos. Now, those with the right abilities, attitude and experience can command excellent reward packages in a wide variety of digital high-tech industries.

The MRO industry is aging. Offering an attractive pathway to young people is proving to be difficult. It’s a two-sided problem. On the one side the industry is inherently conservative. Afterall it’s in the safety business where reputation for quality matters. On the other side the attitudes, beliefs and expectations of younger people are markedly different from those of their potential mentors and teachers. Bridging this divide isn’t easy.

Apprenticeship schemes do help[3]. However, they are often picking up the people who already know they want a career in aviation.

The challenge is not just recruitment but retention. The aviation industry must make it attractive to retain talent. Working in an aircraft hanger, or on the ramp in the middle of a cold winter isn’t everyone’s cup of tea. Especially when comparing stories with a colleague in a nice warm office of a telecoms or social media company.

Building community, professionalism and a love of aviation is a priority. I’ve seen this done in the US. Next April at MRO Americas at the Georgia World Congress Center in Atlanta a competition[4] takes place. It’s an excellent example of how to create excitement in this field. Check it out.




[4] Aerospace Maintenance Council – YouTube

Air Taxi 2

As a quick effort at simple research, I looked at several local government websites searching for Air Taxi or Urban Air Mobility (UAM) or Advanced Air Mobility (AAM). The result was lots of blanks with one or two exceptions[1][2]

There’s numerous articles about e-scooters and how they might be integrated into cityscapes.

Addressing local governments, much of what has been published to date concerns the use of drones. Yes, the use of drones is happening here and now, so this is not such a surprise. However, to me, this was a reminder that the frenetic world of aviation often discussed the future in rooms full of like-minded people. Embracing a wider audience is overdue.

In the case of UAM/AAM, innovations in civil aviation are move beyond airports, upper airspace, and specialist technical interest. If the electrification of flight is to take hold it will touch the lives of many more people than conventional commercial aviation.

These new aviation developments will generate new business models and offer new services. This is challenging stuff. It’s clear to me that, without the agreement of local authorities such enterprises will be dead before they start.

National governments may take a regulatory approach that imposes on local governments. That would be ill advised and ultimately unsustainable. A cooperative partnership would open a smooth transition from transport novelty to accepted everyday part of mobility.

Local authorities will need to adapt their formal local plans to include planning considerations of zoning, land-use, multi-modal matters, environmental impact, construction, utilities/support infrastructure, public privacy and much more.

Local government is a partner in risk management too. Just as highway authorities wrestle with improving road safety so, no doubt, UAM/AAM accidents and incidents will be on their agenda.

Fostering public-private partnerships is talked about but few examples have moved beyond theory and into practice.

POST 1: These issues have been highlighted at ICAO this year Urban Air Mobility and the Role of Air Transport – ICAO 2022 Innovation Fair – ICAO TV

POST 2: The organisation is looking at possible future operations

POST 3: People taking a holistic view



Air Taxi

My daily routine once comprised of walking across a bridge over the Rhine to an office in Ottoplatz in Köln-Deutz[1]. That’s in Cologne, Germany on the eastern side of the river.

In the square outside the railway station is a small monument to a man called Otto. A small monument marking a massive transformation that took place in the way transport has been powered for well over than a century. This monument honours Nicolaus August Otto who created the world’s first viable four-stroke engine in 1876.

Today, the internal combustion engine hasn’t been banished. At least, not yet and Otto could never have known the contribution his invention would make to our current climate crisis. But now, rapid change is underway in all aspect of transport. It’s just as radical as the impact of Otto’s engine.

As the electrification of road transport gathers apace so does the electrification of flying. That transformation opens new opportunities. Ideas that have been much explored in SiFi movies now become practically achievable[2]. This is not the 23rd Century. This is the 21st Century. Fascinating as it is that in The Fifth Element the flying taxi that is a key part of the story, has a driver. So, will all flying cars of the future have drivers?

I think we know the answer to that already. No, they will not. Well, initially most of the electric vehicles that are under design and development propose that a pilot (driver) will be present. Some have been adventurous enough to suggest skipping that part of the transition into operational service. Certainly, the computing capability exists to make fully autonomous vehicles.

The bigger question is: will the travelling public accept to fly on a pilotless vehicle? Two concerns come up in recent studies[3][4]. Neither should be a surprise. One concerns passengers and the other concerns the communities that will see flying taxies every day of the week.

Public and passenger safety is the number one concern. I know that’s easy to say and seems so obvious, but studies have show that people tend to take safety for granted. As if this will happen de-facto because people assume the authorities will not let air taxies fly if they are unsafe.

The other major factor is noise. This historically has prevented commercial public transport helicopter businesses taking-off. Strong objections come from neighbourhoods effected by aircraft constantly flying overhead. Occasional noise maybe acceptable but everyday operations, unless below strict thresholds, can provoke strong objections.

So, would you step into an air taxi with no pilot? People I have asked this question often react quickly with a firm – No. Then, after a conversation the answer softens to a – Maybe.





Corporate Failure

I watched the documentary on the Boeing 737 MAX 8 last night. It’s on Prime[1]. Called Flight/Risk. It starts with the launch of the new aircraft and ends as the aircraft returns to service and the consequences of the disaster that are still rippling through aviation. Seattle Times journalist, Dominic Gates appears frequently. His perspective is one that I was reading as the accidents and following events unfolded.

It’s a well-made production. I my view it focuses too much on whistle-blowers and too little on the appalling design errors made in certifying the aircraft. However, I can understand the choices made by the film makers. It’s primarily aimed at a public audience and not technical experts.  

This was a massive and fatal corporate failure. My recollections of working with Boeing in Seattle, in the mid-1990s are that such events could never have occurred in that era. It was a preeminent engineering company, with a proud heritage and safety was as important as the blood that flows through our veins. What happened in this last decade is beyond shocking.

Now, corrective action is being taken. Efforts are being made to re-establish an effective safety culture. All over the world technical experts have securitised the modified Boeing 737 MAX to the n-th degree. The company expects the Boeing 737 MAX 7 will be certified by the end of the year and the larger MAX 10 in the first half next year.

What is regretful is how long the design and manufacturing industries resisted the introduction of Safety Management Systems (SMS). I remember doing presentations to industry on that subject more than 2-decades ago.

So, what does a bad corporate and safety culture look like? We must recognise it, and not ignore the signs. What concerns me is, however much we have learned from the Boeing 737 MAX saga; it will soon be forgotten. Pasted over like wallpaper.

As if to give me an illustration, I was standing in a high street shop, browsing sale items in the normal way. It’s always nice to pick up a bargain. Even though it was a busy Saturday afternoon, there wasn’t many people in the shop. Behind me, were two store employees chatting away. They didn’t pay much attention to me until they had finished. They were close enough for me to hear most of what they were saying. One of them was the store manager.

Basically, they were having a whinge about the company that owned the shop. One key aspect was the waste of time, as they saw it, of being sent on company training courses where expensive consultants rabbited on to them about matters that were totally irrelevant to their day-to-day business. They blamed the corporate management. They haven’t got a clue, and it’s getting worse was the gist of the chat. They both expressed love of their jobs. It was a cry of desperation and frustration as they feared the company was on the road to go bust.

I guess that’s it. When little, or no communication exists between shop floor, literally in this case, and corporate management then that’s a big indicator of grave troubles ahead.


Moon Mission

The universe is big, I mean really big, but our nearest neighbour is close by. Seeing our unique satellite orbit the Earth is as common an experience watching the weather. No need for a telescope.

The circumference of Earth (distance around Earth at the equator) is roughly 40,000 kilometres (25,000 miles). The distance to the Moon is 10 times the circumference of the Earth, or roughly 400,000 kilometres (250,000 miles[1]). That sounds like a lot but compared with the dimensions of our solar system it’s nothing much.

The first humans walked on the Moon on 20th July 1969. I was 9-years old. I watched the event in our living room on a small black and white TV. Around the globe, hundreds of millions of people watched as Armstrong stepped out on the surface of the Moon for the first time[2]. For good or ill, humanity changed on that day.

A plan for returning humans to the Moon is underway[3]. NASA’s new lunar mission is ready for launch. Called “Artemis” a mission is on the launch pad. In ancient Greek mythology, Artemis was heavily identified with Selene, the Moon.

This project will work with industry and international partners, like the European Space Agency (ESA)[4] to send astronauts to the surface of the Moon. The European Service Module (ESM) will provide for future astronauts’ basic needs, such as water, oxygen, nitrogen, temperature control, power, and propulsion.

It’s a big day. Exploration is a part of human DNA. These are the next steps. I wish the project every success.

POST: Well, we get to use that well used phrase – Space is hard. “Space is hard.” But why? — Elizabeth A. Frank (

[1] 225,623 miles away when it’s at its closest. The Moon’s orbit is not a perfect circle. When the Moon is furthest, it’s 252,088 miles away.




Safety Performance Indicators

What’s happening? Two words, and what seems like the easiest question in the world. Open your phone, look at the screen and a myriad of different sources of information are screaming for your immediate attention. They are all saying – look at me, look now, this is vital and don’t miss out. Naturally, most of us will tune out a big percentage of this attention-grabbing noise. If we didn’t life would be intolerable. The art of living sanely is identifying what matters from the clutter.

So, what happens in aviation when a Chief Executive or Director turns to a Safety Manager and askes – what’s happening? It’s a test of whether that manager’s finger is on the pulse, and they know what’s happening in the real world as it happens.

This is a place I’ve been. It’s a good place to be if you have done your homework. It’s the way trust is built between the key players who carry the safety responsibility within an organisation.

One of the tools in the aviation safety manager’s toolbox is that of Safety Performance Indicators (SPIs). In fact, it’s part of an international standard[1] as part of a package for conducting safety assurance. Technically, we are talking about data-based parameters used for monitoring and assessing safety performance.

The ideas are simple. It’s to create a dashboard that displays up-to-date results of safety analysis so that they can be viewed and discussed. Like your car’s dashboard, it’s not a random set of numbers, bar-charts, and dials. It should be a carefully designed selection of those parameters that are most useful in answering the question that started this short blog.

That information display design requires great care and forethought. Especially if there’s a likelihood that serious actions will be predicated on the information displayed. Seems common sense. Trouble is that there are plenty of examples of how not to do this running around. Here’s a few of the dangers to look out for:

Telling people what the want to hear. A dashboard that glows green all the time it’s useless. If the indicators become a way of showing off what a great job the safety department is doing the whole effort loses its meaning. If the dashboard is linked to the boss’s bonus, the danger is that pressure will be applied to make the indicators green.

Excessive volatility. It’s hard to take indicators seriously if they are changing at such a rate that no series of actions are likely to have an impact. Confidence can be destroyed by constantly changing the tune. New information should be presented if it arises rapidly, but a Christmas tree of flashing lights often causes the viewer to disbelieve.

Hardy perennials. There are indicators, like say; the number of reported occurrences, which are broad brush and frequently used. They are useful, if interpreted correctly. Unfortunately, there’s a risk of overreliance upon such general abstractions. They can mask more interesting phenomena. Each operational organisation has a uniqueness that should be reflected in the data gathered, analysed, and displayed.

For each SPI there should be an alert level. It can be a switch from a traffic light indication of green to amber. Then for the more critical parameters there should be a level that is deemed to be unacceptable. Now, that might be a red indicator that triggers a specific set of significant actions. The unscheduled removal or shutdown of a system or equipment may be tolerable up to a certain point. Beyond that threshold there’s serious safety concerns to be urgently addressed.

The situation to avoid is ending up with many indicators that make seeing the “wood from the trees” more difficult than it would otherwise be. Afterall, this important safety tool is intended to focus minds on the riskiest parts of an operation.

[1] ICAO Annex 19 – Safety Management. Appendix 2. Framework for a Safety Management System (SMS). 3. Safety assurance. 3.1 Safety performance monitoring and measurement.

Is Airworthiness Dead? 2/

Where I left the discussion there was a question mark. What does conformity mean when constant change is part of the way an aircraft system works?

It’s reasonable to say – that’s nothing new. Every time, I boot up this computer it will go through a series of states that can be different from any that it has been through before. Cumulative operating system updates are regularly installed. I depend on the configuration management practices of the Original Equipment Manufacturer (OEM). That’s the way it is with aviation too. The more safety critical the aircraft system the more rigorous the configuration management processes.

Here comes the – yes, but. Classical complex systems are open to verification and validation. They can be decomposed and reconstructed and shown to be in conformance with a specification.

Now, we are going beyond that situation where levels of complexity prohibit deconstruction. Often, we are stuck with viewing a system as a “black box[1]. This is because the internal workings of a system are opaque or “black.” This abstraction is not new. The treatment of engineered systems as black boxes dates from the 1960s. However, this has not been the approach used for safety critical systems. Conformity to an approved design remains at the core of our current safety processes. 

It’s as well to take an example to illustrate where a change in thinking is needed. In many ways the automotive industry is already wrestling with these issues. Hands free motoring means that a car takes over from a driver and act as a driver does. A vehicle may be semi or fully autonomous. Vehicles use image processing technologies that take vast amounts of data from multiple sensors and mix it up in a “black box” to arrive at the control outputs needed to safely drive.

Neural networking or heuristic algorithms may be the tools used to make sense of a vast amount of constantly changing real world data. The machine learns as it goes. As technology advances, particularly in machine learning ability, it becomes harder and harder to say that a vehicle system will always conform to an understandable set of rules. Although my example is automotive the same challenges are faced by aviation.

There’s a tendance to see such issues as over the horizon. They are not. Whereas the research, design and development communities are up to speed there are large parts of the aviation community that are not ready for a step beyond inspection and conformity checking in the time honoured way.

Yes, Airworthiness is alive and kicking. As a subject, it now must head into unfamiliar territory. Assumptions held and reinforced over decades must be revisited. Checking conformity to an approved design may no longer be sufficient to assure safety.

There are more questions than answers but a lot of smart people seeking answers.

POST 1: Explainability is going to be one of the answers – I’m sure. Explained: How to tell if artificial intelligence is working the way we want it to | MIT News | Massachusetts Institute of Technology

POST 2: Legislation, known as the Artificial Intelligence Act ‘Risks posed by AI are real’: EU moves to beat the algorithms that ruin lives | Artificial intelligence (AI) | The Guardian

POST 3: The world of the smart phone and the cockpit are here How HUE Shaped the Groundbreaking Honeywell Anthem Cockpit

[1] In science, computing, and engineering, a black box is a device, system, or object which produces useful information without revealing information about its internal workings.