Wednesday, October 19, 2011

Fog

All through winter, i have dealt with severe icing (that is, by Australian standards to all those Canadians reading!), i have dealt with storms, weather, low cloud, low visibility, high cross-winds, virtually everything mother nature could throw at me - except fog!


Now, we weren't trying to land, so it wasn't a big deal at all. We were coming off the overnight and arrived at the airport with 200 metres visibility. However, this meant we couldn't depart. By Australian standards, the Dash-8 is a 'qualifying' twin engine aircraft - That is we are multi crew, have an autofeather system, above 5,700kg and have a guarenteed climb performance on one engine above 2.4% in the second segment (This relates to the gear up in take off configuration to an acceleration altitude, which for us is normally 500ft above the aerodrome elevation - unless there is a special procedure due to high terrain.)

So our problem became the required vis for take-off. Normally is it 550 metres, but the runway lights at this aerodrome were 90 metres spaced, as opposed to the normal 60 metres, which meant we required 800m visibility to legally take off. Australian airspace used to have low-visibility operations, and my company teaches it in the sim for training, as there are specific procedures and requirements that we need to follow to allow us to operate low vis. Low vis is visibility down to 350 metres, however it has been abandoned at the moment, and currently 550 and 800 metres are the legal minimums for us to take-off.

So for the aerodrome we were at, this required us at the very least to be able to see 8 rows of runway lights so count the 800 metres. Unfortunately for us, we were able to see about 3 lights, and to add to it, the runway has a slope in the middle, which prevents you from seeing lights over a slight ridge.

The captain and myself did an inspection in an airport ground vehicle to check out each runway end, and after listening to the automated weather unit, we decided to give it a shot. We started both engines, taxiied out the end of both runways, with all intention of taking off, but it wasn't to be! We ended up taxiing back on the apron to wait it out, and unloaded our eager passengers. We figured it would be a bit of a wait and it was more comfortable for them in the terminal.

So we were forced to wait it out, until it lifted - about 2 hours later! We finally departed through a very thin layer of overcast cloud at this point into a smooth beautiful clear sunny day everywhere else.




To all those that follow, thanks for the continued reading. I have been slack at posting and taking pictures of recent times, it's hard to know how much i can say or post about now that i'm flying for this company.