Originally Posted by
Equivocal
Although many aspects are good, there is one potential problem with some of the suggestions about RWSL, particularly if it is only installed at an airport where it is perceived that 'there is a need'. The mindset with RWSL is that when the red lights are off, we can cross/roll, when you then arrive at an intersection or line up on a runway where there is no need, at least half the protection of the system is lost. There is an additional gotcha if you are used to operating from airports with RWSL and then find yourself somewhere with a less sophisticated system, the usual mindset can be a problem.
My take on RWSL is: to cross a runway or takeoff, you need a) a clearance from ATC, b) to be confident from your own assessment that it is safe and c) that RWSL haven’t activated, telling you that there is (or will be shortly) something on the runway that you may not be aware of. I see it as a last fail-safe or backup to procedures already in place, similar to TCAS. Does it encourage a lack of rigour? I don’t know but I would guess the safety benefit is greater?
I've also got a slight hesitation about the control systems, which are driven by ASMGCS data, and rules about when the RWSL is activated - having had some involvement in setting up RIMCAS (Runway Incursion Monitoring and Alerting System) at a pretty simple airport, getting the rules correct so there are no false alerts is not easy. With RIMCAS, the alerts are 'only' raised to ATC and humans can assess whether the alert is legitimate, although there is often little time for this (or, worse, an alert is ignored because 'it always goes off when this happens'), RWSL, as I understand it, is fully autonomous - the system is most useful at complex airports where the ruleset which does not produce erroneous operation will be difficult to compile. And then, of course, one day ATC will say, "Ignore the THLs, clear for take-off". The tech-savvy will now start talking about AI......
Valid points but I think the autonomy is a big positive, for the day when all the holes in the cheese line up. Would have made what happened in DXB into a complete non-incident? Ignoring the THLs would be like ignoring an RA, GPWS or RAAS alert... Last chance to avoid a potential disaster.
RWSL is probably the best system around at the moment , however it is a pure US/FAA system , still defined as an advisory system (*) and only installed in 20 airports in the US. and as far as I know is not for export ( waiting to be corrected if I am wrong)
I was under the impression that it was installed at Paris CDG; if it isn’t the system is a dead ringer and is called RWSL (and if it was truly a French design it would be called LSRW or something...)