PCN
Prof. Airport Engineer
Joined: Oct 2000
Posts: 726
Likes: 0
From: Australia (mostly)
Hi, I've written this up a few times. so let me cut and paste the answer from previous discussions. But first let me reassure you - operating at ACN > PCN by 20% is no more worrying than taking off with say a 20% greater weight than calculated TOW. For a red-blooded fully paid up large handlebar mustache'd pilot, it's easy. For the rest of us:
An aircraft can sink into the runway if the ACN is way > PCN – it just depends on how much greater. A small overload, like 10% above, is usually OK and is common. I have gone to a larger overload occasionally but only with a slow build-up over several years and the runway being inspected by an engineer after each overweight flight. An overload of 25%+ is considered an emergency at my airports. And most international airports operate to the same or more conservative standards. Don’t forget to get a concession for tyre pressure as well if needed.
Can you get found out and made liable by the authorities if you operate and your ACN > PCN? Yes. That’s one of the things I do for airports. I back-calculate the flight operation and get a pretty close idea of the takeoff weight (and PCN). And if it is above the published PCN or the airport operator’s PCN concession for your flight, you are liable for any damage.
If you have a diversion airport, then get a concession from them in advance. Most concessions are arranged by Ops Department with the airports and most are long-standing concessions. The number of flights per year, weights, etc are considered by the airport before giving the concession. A diversion is pretty minimal in terms of ops, and not usually a problem (except in Israel).
An aircraft can sink into the runway if the ACN is way > PCN – it just depends on how much greater. A small overload, like 10% above, is usually OK and is common. I have gone to a larger overload occasionally but only with a slow build-up over several years and the runway being inspected by an engineer after each overweight flight. An overload of 25%+ is considered an emergency at my airports. And most international airports operate to the same or more conservative standards. Don’t forget to get a concession for tyre pressure as well if needed.
Can you get found out and made liable by the authorities if you operate and your ACN > PCN? Yes. That’s one of the things I do for airports. I back-calculate the flight operation and get a pretty close idea of the takeoff weight (and PCN). And if it is above the published PCN or the airport operator’s PCN concession for your flight, you are liable for any damage.
If you have a diversion airport, then get a concession from them in advance. Most concessions are arranged by Ops Department with the airports and most are long-standing concessions. The number of flights per year, weights, etc are considered by the airport before giving the concession. A diversion is pretty minimal in terms of ops, and not usually a problem (except in Israel).
