(Aircraft Gallery Group, FB)
The vast majority of birds are diurnal, meaning that they are active during the day and sleep at night.
But, it’s well-known that owls fly at night, and that there are over 200 species of them on all continents, except Antarctica.
In fact, there are 6 groups of birds that are most prone to fly at night, with some almost exclusively at night. They include the owls, the mockingbird, night herons, killdeer, the nightjar, and the petrel.
Most fly at night do so for similar reasons, i.e., because they see better at night, they can hunt in stealth fashion and swoop up prey, or they sing for mating purposes (mockingbird). Or, they buzz at night because they are better protected from their own predators, like killdeer.
What is less known is that the birds that fly at night do so at higher altitudes and often over water/ocean, or near island and coastal areas.
This makes it very relevant for aviation and bird strike risk. Also, there are more and more indications that pilots can prepare for this better, especially those of rotorcraft, like helicopters and quieter eVTOLs.
Read on and/or join for Airline Behavioral Economics for free.
By the numbers
Statistics on bird strikes vary from source to source and country to country.
No surprises there.
But while almost two-thirds (61.2%) of bird strikes have no effect and allow continued flight, which still represents almost 4300 incidents per year in Canada alone, others strikes are more dangerous:
8.9% required a precautionary or forced landing (603 times in 2017)
2.5% required an aborted take-off, and
2.0% involved a serious engine ingestion.
It is therefore very important that the collection and analysis of detailed data is done against a backdrop of precise information about contexts, live meteorological data, and bird breeding patterns.
This can assist in the development of effective risk management strategies.
But in the USA, the FAA was not doing any detailed quantitative research on bird strikes until 1995, so this practice is fairly recent.
Definition
Nonetheless, what is a bird strike, technically, in aviation terms you may ask?
Here, the authorities provide some useful guidelines.
A bird strike is deemed to have happened when:
a pilot reports a bird strike [yes, no kidding]
aircraft maintenance personnel identify damage to an aircraft as having been caused by a bird strike [usually includes blood];
personnel on the ground report seeing an aircraft strike one or more birds;
bird remains—whether in whole or in part—are found on an airside pavement area or within 200 feet of a runway, unless another reason for the bird’s death is identified.
In case you are wondering, strikes against other classes of wildlife are treated with less formality, but they still fit into the same definitions.
And contrary to common belief, bird strike reporting is not mandatory in most jurisdictions, for a variety of reasons including the assumption it would raise public fears.
Pilots that do report strikes are not always able to determine the circumstances, the type of species involved, and the extent and cost of damage to the aircraft or engines.
Today, there is little that can be done to better prevent bird strikes as most bird strike risks are communicated by air traffic control based on the analyses and live updates they receive from the ground. (Every seen those yellow cars near runways on bird patrol?)
But recently, the FAA released an updated InFO (Information For Operators) (23005) to provide more information to helicopter operators as well as flight schools. The background was that there had been an increase in bird strikes involving rotorcraft.
And there is concern about the entry of eVTOLs into service. A great deal of concern, especially near urban areas and parks.
So, the Aviation Rulemaking Advisory Committee (ARAC) was to provide recommendations regarding bird strike protection rulemaking, policy, or guidance because of these new concerns.
One of the recommendations that came out was to use bird strike resistant windshields, but there were other words of wisdom directly aimed at operators and pilots, too. They are recommended to:
Learn about the local bird population and use it to plan and fly routes.
Among the key considerations are seasonal migratory times and concentration patterns within the typical operating area.Reduce airspeed when practical.
Three out of four bird strikes (77%) occur during airspeeds greater than 80 knots. When operating rotorcraft in areas of high bird concentrations, the likelihood of a damaging bird strike goes up as airspeed increases. When operating in these areas, fly at 80 knots or less, particularly when at lower altitudes.Increase Altitude.
Increase altitude as quickly as possible and practical, when allowed by other flight variables. There is a 32% decrease of bird strike likelihood for every 1,000 feet gained above 500 feet AGL. Also, birds fly higher at night, so an increase in altitude may be needed even more at night than during the day.Wear personal protective equipment (PPE).
A helmet and visor, at least for the crewmembers, should be worn when practical. This is one of the simplest acts that can improve safety in rotorcraft operations.
Use taxi and/or landing lights
[in a continuous mode during sunny conditions and at night when practical, and use a 2-Hz pulsed mode during partly cloudy conditions, and/or install lighting systems that provide the equivalent with white incandescent, high intensity discharge (HID), or light emitting diode (LED) lighting]
(InFO 23005 ©)
We often speak of human-machine interaction, but given birdstrike analyses, one could speak of animal- and human-machine interaction to better coexist in areas at risk.
Perhaps future technology will exist on board aircraft (especially eVTOLs) to broadcast danger to animals in a way they can hear or understand, to create safe corridors. It would not surprise me, as simple tools exist today that can notify deer of approaching vehicles.
Either way, it always fascinates me how much we can learn from nature that we can then apply in ways we go about doing our business. The flying species are no different.
Finally, if aircraft one day become very silent like owls when they conduct their hunting, we have renewed concerns about protecting birds and human life. I compare that to EVs to which we added sound to notify pedestrians.
Wishing you all a wonderful day, and greetings from Montréal.
Ricardo
Montreal, Tuesday, 30 May 2023
Feel free to contact me for questions, comments, or a chat:
ricardo(at)pomonaadvisors(dot)com
my general email has changed to: info(at)ricardopilon(dot)com