Are the safety standards for all large aeroplanes the same? No, they are not. I’m never sure if the public naively expect this to be the case. I’m sure it’s not something that goes through the mind of every air traveller. Looking up at an aeroplane, flying overhead, this is not a thought that instantly comes to mind. Even watching them take-off and land at a busy airport.
A large aeroplane is a large aeroplane – surely. Well, not exactly. Several issue come into play when addressing the safety standards for large civil transport aeroplanes. For example, when did the type of aeroplane first go into service? What is it being used for? Where is it flying to? How many people are on-board?
One place to start with any discussion on this subject is with the basics. For a start an aeroplane is heavier than air and its power driven. Immediately, two important factors pop out of that definition. One: weight counts. Two: operating engine(s) are needed.
Almost lost in the mists of time are the reasons for dividing the world of transport aeroplanes into two categories. Simply called – large and small.
Underlying this basic categorisation is an historic assumption. This is an assumption upon which civil aviation safety regulation has been built. Namely, that efforts need to be made to ensure large aeroplanes are safer than small aeroplanes. One way of looking at this is to consider a spectrum of risk, and several parameters of concern.
Let’s start with the question above – what is it being used for? A transport aeroplane can be used to carry cargo or passengers, often both. The number of crew and passengers carried can range from 1 to 850[1]. In fact, for large aeroplanes, there’s no upper limit written into international standards. However, the term “very large aeroplane” is coined for the upper end of weight or passenger numbers carried. Sadly, the very largest of these very large aeroplanes (cargo), the Antonov An-225 Mriya, was destroyed by war.
Although, a matter of primary concern is the number of passengers carried, and therefore at risk in the event of an incident or accident, the main dividing line in the regulatory landscape between large and small aeroplanes is weight.
To some extent this has a foundation. It could be viewed that in the event of an incident or accident any resulting impact will be more severe the greater the weight of the aeroplane. This is where a parameter called the MTOW, or Maximum Take-off Weight, comes in. This number includes the total weight of an aeroplane, crew, fuel, passengers, and cargo.
Today, we divide the world of large and small aeroplanes based on MTOW. Yes, the maximum number of passengers that can be carried comes into the equation too. The question I have is, should that be the number one consideration?
[1] https://www.airwaysmag.com/legacy-posts/top-10-largest-passenger-aircraft
John Vincent 