Low-visibility take-offs / landings & RTOs
 

Hello all

In light of the report (posted in the FD forum) into the high-speed aborted take-off at Dublin some time ago, I wonder if I can ask two questions on that topic that are unrelated to each other?

1) I understand that aircraft are separated at greater distances from each other in low visibility weather to reduce further the risk of a collision. (For example, it was explained on another thread in this forum that only one aircraft at one time flies the ILS at LHR in foggy weather for this reason). On a clear day, you will be able to see pretty far down the runway and spot if there is an incursion. But what happens in fog/low visibility when you can only see a couple of hundreds of metres ahead of you? How do you know for certain that you aren't going to hit something half-down that you can't see from the start and that you are now travelling too fast to avoid? My question applies to landings too, where you land only being able to see the minimum amount of runway to be 'visual'. In these weather situations, are you putting all your trust in ATC/others crews to ensure your runway is clear, or is there an automated system that helps you? I believe TCAS operates only in-flight?

2) Speaking more generally on the point of RTOs, would it be fair to say that broadly speaking most professional pilots will perform at least one 'real' go-around in their professional flying career, whereas most professional pilots will never carry out a rejected take-off and even fewer will perform a high-speed rejected take-off (other than in the six-monthly simulator training), given that they are such a rare occurrence?

Thanks for your help.
Nick

1) Strict airport regulation of traffic/surface movement radar/unambiguous signage and crew training to list a few of the 'precautions'. However, if someone by mistake drives a fuel tanker across a foggy runway in front of a high-speed metal tube, there will be a big bang. The 'separation' on approach is to avoid disruption of the ILS signal, not the 'collision risk'.

2) I would say yes, absolutely.

EDIT : Just read your query properly!:ugh: I suspect ALL pilots will at some stage carry out at least one RTO, but the high-speed case less likely.

One aircraft at a time? Definitely not. The separation will be increased for the reason given by BOAC but never to the extent of one at a time. The Air Controller in the tower determines the spacing and various factors are taken into account. 6 miles is a good starter and this maybe increased if pilots have trouble leaving the runway or a turn off is closed, etc.

Many major airfields have surface radar which will show any obstructions on the runway. It is ATC responsibility to ensure that the runway is clear.

2) In the first ten years of my career I had four RTOs (one high speed) and a dozen go arounds (one during my first ever line training sector!). The last time I went around was two days ago.

Am I unlucky or just crap?!:}

You don't. You have to have faith in ATC - but without a ground movement radar, ATC also has to have faith in flightcrew following instructions. This is what happens when it all goes wrong:-

ASN Aircraft accident McDonnell Douglas MD-87 SE-DMA Milano-Linate Airport (LIN)

Heathrow is also equipped with RIMCAS - (Runway Incursion Monitoring and Collision Avoidance System), whereby an alarm is triggered on the A-SMGCS (Advanced Surface Movement Guidance & Control System) screen if any vehicle or aircraft infringes the LSA. Perhaps Gonzo will be along soon to explain further.