If you’re fit in safety management you already know that safety is defined as the absence of unacceptable hazard. This is a very formal way to say that as hazards are present in any system and must be mitigated to reach an acceptable level of safety. A typical approach is to classify hazards according to their severity and probability of occurrence. This results in a visual hazards chart where the limits between what is acceptable or not must be defined. If a hazard is located in the “unacceptable” area, mitigation measures must be implemented to reduce its impact or probability of occurrence to bring it back in the “acceptable” area.

I know that this does not sound really “aviation-oriented” for the time being, but you’ll soon see what is the point… This classification principle sounds very systematic and almost scientific but it is only high-precision guesswork. The severity and probability of occurrence are not really easy to evaluate but this is nothing in comparison to the definition of the acceptable and unacceptable. Is a mid-air collision every 50 years acceptable ? How many runway incursions leading to a go-around are acceptable per year ? High-precision guesswork. Ask the same question to two professionals, you’ll get three different answers.

The definition of what is acceptable or not can also vary with time and events, and sometimes rather abruptly – as shown after an accident in Samedan (LSZS). Samedan is the highest airport in Europe, at 5′600 feet AMSL, in Eastern Switzerland, in the vicinity of Davos. The quantities of snow in the heart of the Alps in such a cold winter are quite impressive but the runway is properly de-snowed. Snow-walls along the runway are quite common and even a few meters away from the runway borders they can be well over a meter high. Because of its proximity with Davos the airport is used intensively during the World Economic Forum, but also throughout the whole ski season by rich skiers. Business jets operate there frequently.

On the 12th of February, a Falcon 100 skidded off the runway after landing, after what its wingip did hit a snow-wall. The preliminary description contained in the accident notification issued by the investigation body reads: “Aircraft touched down left of centreline with the right wing first, then with right main gear. The aircraft drifted to the left and touched with the left wing a snow wall at the runway edge. The aircraft nose hit the snow wall frontally. The aircraft turned to the left and broke into two parts.” The two crew members were fatally injured and the passenger severly injured. No finger-pointing here, just facts. Despite being unusual in comparison with other airports, the conditions that prevailed were not out of the norm for Samedan.

After the accident, the Federal Office for Civil Aviation (FOCA) decided to close the airport, because the height of the snow-walls is above what is prescribed in ICAO standards. Standards provide good guidance but can not always be applied by the letter. As long as they are well supported and accepted, deviations are acceptable. The deviations in Samedan were well known by the airport, by FOCA and by operators using the airport.

What does this all mean from the safety analysis point of view ? The presence of snow-walls was certainly identified as a hazard, which was possibly reduced via some mitigation measures to finally land in the “acceptable” area of the evaluation matrix. Because of various causes which will be determined by the investigation this hazard possibly contributed to an accident. Not to 0.0001% of an accident, but to an actual one. Does this accident have an impact on the previous classification of the hazard ? Is the snow more dangerous after an accident ? The answer is obviously no. If you hurt yourself with a knife, the knife is not more dangerous after the accident than before…

There is certainly something to learn from this accident – there’s something to learn from any accident – but closing the airport and requiring the application of standards that were previously not applied for good reasons looks to me like a bit of a panic-based reaction. The accident occured to a Falcon 100, right ? So why not ground the whole Faclcon fleet ? And the accident occured on a snowy airport. Close all of them ! After all, this “aviation”-thing is way to risky. This shall stop now ! Stop the whole aviation system, there was an accident !

There is however a positive side in this story. The airport resources being simply unsufficient to match the new requirements suddenly dictated by an almighty authority, it called for help. Many local construction companies sent trucks, snow-cleaners and bulldozers, and more than 300 simple citizens with gloves and shovels (well… some politicians as well) joinded the effort, voluntarily.  After one and a half day, the airport was matching the newly required standards and operations restarted. This was a splendid support demonstration from the local business and people to their airport. There is no airline activity in Samedan… people shown their attachement to a 100% General Aviation airport, and this makes me feel really good