FLIGHTPLAN. Landing in fog: The memory’s hazy

I fly the A-320 family of aircraft which is the Airbus A-320, A-321 and the A-319. Flying in normal conditions means that you will be able to see the runway at 200 feet while landing. At that time, when you are less than a mile from the threshold, or the physical beginning of your touchdown zone, you disconnect your auto pilot. Your spatial orientation or your depth perception and your alignment with the runway are correct.

The aircraft comes in on a stabilised approach till 200 feet. If you see the runway, you land. Otherwise you push in the power and you go away. This is the CAT I approach, when the visibility is 800 metres or more.

The situation is different when it comes to fog conditions, or CAT III landings (CAT II and CAT IIA are more airfield dependent). CAT III B landings have the lowest visibility at 75 metres. You cannot see the runway, so you have to use auto pilot even for landing.

It is a very uncomfortable feeling because you are riding in the dark. You will at best see one light, the central line light. You are going down at 200 kmph and you see nothing. We (pilots) like to look far into the distance so that we can get a good depth perception from our peripheral vision. But here you do not get any depth perception from your frontal vision and there is no peripheral vision.

The scariest part is trying to find your bay after landing. She (the plane) will land herself but after that you are lost. So you either follow a jeep or you have CAT IIIB auto land taxi lighting like in Delhi. I lost my way last year when conditions deteriorated very quickly.

Low visibility take-offs are more scary as there is no auto take-off. You can have an auto land but not an auto take-off. That is why for low visibility take-offs you need at least 125 metres of visibility.

CAT IIIB landings are not very common. We perhaps have one or two a year and that too only in Delhi. Weather conditions which require you to go in for auto landing only exist in Delhi. It is also the only place equipped for CAT IIIB in India. A plane becomes CAT IIIB only if she has done a certified auto land. So I do an auto land and fill up the log book giving details like CAT IIIB auto land carried out satisfactorily on so and so runway. I also fill up a form and show where she touched down and what the conditions were. This certification lasts for a month. So each aircraft that is flying in CAT IIIB conditions has to do a certification once a month.

Not all CAT I pilots are certified to be CAT III pilots. A pilot who does CAT IIIB can also do CAT I and CAT II. To be a CAT III pilot you have to go through your ground classes for two days to understand how the system works and do simulators for six hours to demonstrate go-arounds and CATIII B auto landings.

As a captain and co-pilot, as a set up, you have to demonstrate CAT IIIB landing on a regular line flight which means when you are carrying passengers. You can keep the verification valid if you do one a year.

(The pilot, who is not authorised to speak to media, requested not to be named; as told to Ashwini Phadnis)

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