Strobes ...

[Young Paul]

A couple of times in the last few weeks, we've been waiting in turn at the holding point behind a Boeing aircraft. On receipt of a line-up clearance ("Behind the landing aircraft at 3 miles"), and with the runway guard lights still up, the pilots of the aircraft put their strobes on. It was over a minute until they entered the runway.

On both occasions, the pilots were quietly challenged about this. On one occasion, they switched the strobes off. On the other occasion, they said, "SOPs....".

Has a new SOP been introduced somewhere that on receipt of a line-up clearance (not on entering the runway) strobes should be switched on? And if so, isn't it reasonable to say that part of the "line-up" clearance is actually the holding point guard lights changing - so that the "line-up" clearance isn't actually in force until the lights give permission to line up as well? Saying this wistfully - sitting behind an aircraft with strobes on for a minute is not great for night vision. And I can't really see what safety function this would be achieving.

[Intruder]

Different airlines have different SOPs. Airlines have different SOPs for different airplanes. So, an anonymous pilot in an anonymous Boeing airplane may well be following his SOP...

Some SOPs use switch positions as signals to the pilots that a specific clearance has been received (e.g., Taxi and Turnoff lights when Landing Clearance is received). It is not beyond comprehension that "All except landing lights" are turned on when clearance is received to Lineup and Wait, as in this quote from an anonymous SOP for an anonymous Boeing airplane:
Cleared onto departure runway | All except Landing
That SOP does NOT enter into a philosophical discussion of what the Controller may be thinking or doing when he gives a clearance. OTOH, is DOES tell the anonymous pilot that all such clearances must be acknowledged. Habit patterns (move the appropriate switches/buttons when clearance is acknowledged) are built for the general case, and some pilots are more bound to habit patterns without interruption...

[Young Paul]

Yeah, I'm a bit familiar with that conceptually. I just wondered whether anybody had any insight into a procedure that had changed.