Much has been written about the quick thinking and disciplined organisation that allowed the brave Japan Airlines crew to evacuate their passengers safely and live up to the exemplary safety record of aviation operations. But of course, we tend to focus on the consequences (which could have been much worse!), and not realise that the actions of those involved tend to be similar, whether near misses, or disastrous. As Shawn Wildey has just pointed out “We need to do more about protecting runways…there are a lot of near misses (look at the snapshot below of just a year) …let’s not forget Tenerife.”
So, wanting to learn more we got ChatGPT to build a quick FRAM to explore the issues, the result is shown below.
What this shows clearly is the complete reliance on the one channel of communication to control landing, taxiing and take offs, for multiple simultaneous movements. The safety record is thus heavily dependent on the undoubted excellence of the Air Traffic Controllers, as they seem to constitute a single point of failure. (I would be relieved to be corrected if I have misrepresented the issue).This seems both unsafe and unfair to totally rely on human oversight, (however expert and professional) in an archetypal complex sociotechnical system.
A recent video (Av Safety investigation video – runway incursion | Civil Aviation Safety Authority(casa.gov.au), thus concentrates on the “Human Factors” available to increase the reliability and minimise pilot errors. Their recommendations are sensible, but do they address the real issues? Entreaties to recognise information overload, fatigue, confirmation bias are all a relevant and naturally understandable response, common to almost all large organizations, with much invested in their existing systems. But perhaps more enlightened thinking that might allow a more objective approach, unafraid to challenge “the system” is more relevant to its complexsociotechnicality.
Perhaps it’s the “system” (st—–d?)
Looking at the Uberlingen incident for the Swiss Government, (another prime candidate system needing a FRAM analysis)there was an automatic collision avoidance system was involved.
This Traffic Collision Avoidance System (TCAS) is a safety net designed to prevent mid-air collisions between aircraft. Here’s a brief overview of how it works:
- Transponders: Aircraft equipped with TCAS are equipped with transponders, which are electronic devices that automatically transmit information about the aircraft, such as its identity, altitude, and position.
- Interrogation and Replies: TCAS operates by periodically sending out interrogations to nearby aircraft equipped with transponders. These interrogations are like electronic “questions “asking for information. Aircraft transponders, in turn, reply to these interrogations with their own information.
- Resolution Advisories (RAs): If TCAS detects a potential collision threat, it issues Resolution Advisories (RAs) to the flight crews of the involved aircraft. RAs provide guidance on what action the pilots should take to avoid a collision. There are two types of RAs: Climb Advisory(CA): If a collision threat is detected and a climb is necessary to avoid it, TCAS issues a Climb RA, indicating the required rate of climb. Descend Advisory (DA): If a descent is necessary, TCAS issues a Descend RA, specifying the required rate of descent.
- Coordinated Manoeuvres: Both aircraft involved in a TCAS resolution advisory receive complementary RAs. For example, if one aircraft receives a Climb RA, the other will receive a Descend RA. This ensures that the aircraft move away from each other safely.
- Pilot Discretion: While TCAS provides advisories, it’s ultimately the responsibility of the flight crew to follow these advisories.
Pilots are trained to prioritize TCAS RAs over other air traffic control instructions when a conflict is detected. It’s important to note that TCAS is just one layer of the overall air traffic control and collision avoidance system. It works in conjunction with ground-based radar, air traffic control instructions, and other safety measures to ensure the safe and efficient movement of aircraft in controlled airspace. “So, a question that begs to be asked, is that if the aircraft are telling each other where they are, surely some sort of geofencing, or automatic segregation and warnings of potential safety margin incursions, can apply on the ground as well as in the air. (granted some major electronics would be needed to distinguish signals from noise).But if not this what? To maintain aviation’s pre-eminence in safety thinking, don’t we need to plug this glaring gap?
(PDF) Runway Incursion incidents. Available from: https://www.researchgate.net/publication/377147564_Runway_Incursion_incidents [accessed Aug 21 2024].