Sunday, 11 April 2010

Time to Spare - Go By Air

Last week, I had to go through the torment of my annual multi-engine renewal, which is rather like having to take your driving test each year but with the added bonus of the examiner turning-off one of the engines at a critical time in the flight. Of course, with the tragic events that took place in Russia yesterday, my thoughts are with the Polish people and this gets me thinking about what on earth might have happened, without trying to pre-judge the conclusions air accident investigation which will take place.

From what I can discover, 'Smolensk military' has no precision landing aids and was sufficiently blanketed in fog for an earlier transport aircraft attempting to land, to divert to Minsk. While Poland is in Europe and is an ICAO/EASA signatory, when it comes to our rigid civil air-safety standards, what we appear to have in this incident is a refurbished Presidential Tupolev which is rather less than 'State-of-the art' and an experienced Polish Air Force crew under pressure to reach Smolensk in time for an important remembrance ceremony of great historical significance.



What surprises me, is that the pilot reportedly tried three failed approaches and collided with trees a mile from the runway on the fourth. Normally, you would not expect the aircraft to descent below 1000 feet unless the runway visibility was equal to or exceeded the published minimum and in the case of a non-precision approach the aircraft, would not descend below a published Minimum Descent Altitude (MDA) unless the required visual reference was first obtained. If an aircraft collides with the tree-tops then it's clearly descended below its minimums for one reason or another, (pilot error or engine failure being the most common) and in more modern aircraft with 'glass cockpits' you set this as a reference altitude on the primary flight display (PFD) and that's when you hear the computerized voice call 'Minimums' when you reach it. There's a good example of this in the embedded video of a precision approach in an A320.

Without all this, the pilot and co-pilot are reduced to using a stopwatch from the start of the descent from a known approach fix or distance from the airfield, this being a 'sweaty' experience in the extreme in poor visibility, not as accurate as one would like but safe, as long as the aircraft remains at or above the platform height or MDA until the pilot either sees the runway or reaches the Missed Approach Point in a calculated number of minutes and seconds.

With the flight recorders quickly recovered, we may discover what took place rather quickly but I'm not encouraged by reports of the Russian security police confiscating any camera footage of the tragedy from waiting journalists.

The old adage that there are 'Old Pilots and bold pilots but no old, bold pilots', still rings true but the this month I discovered that one veteran aviator I know, used to fly for 'Air America', which in some ways proves it wrong. Now he has some really interesting stories to tell!