And so it is that common sense no longer prevails upon our society or our industry. Has anyone simply asked themselves, "why have them on during flight?"
In decades gone-by - in places where most of the worlds airplanes where built - VFR flight didn't exist above 10,000 feet. The idea was that the landing lights should be on so that the VFR traffic could see those fast moving airplanes, thus preventing things like B727's and C172's colliding as was the case with PSA flight 182.
Pre 1971 in the Australian area there was no obvious history of landing light use at height. The first time I saw it used was in DC3s in Papua New Guinea during famine relief flights in 1971/1972. VMC (well, almost) at 12000ft it was usefull to see opposite direction lights. With very high terrain, weather and poor performance, there was not much chance for level choices to give vertical separation. After that landing light use spread to Australia. Maybe we spread it to the rest of world? It was a good idea then and still is.
So (I'm assuming we're in the same company) why the *@** does everyone, and I mean everyone, turn them off with flaps up? Everywhere?
Perhaps because that little word "consider" has been interpreted by the more over-zealous (read fanatical) TCs and Capts to mean "must turn them off"? Then any FOs brave or foolish enough to think for themselves (not many I fear - they're trained as pavlovian robots through no fault of their own) discover that not turning them off usually results in a lecture on this illusiory fuel saving thereby calling their zealotry into question so it just becomes a de-facto SOP. And as "everyone" does it it becones assumed that it is SOP...and thus wrong to leave them on. These youngsters have no experience or concept of "industry standard" so cannot know better. And the company can hotly deny this when they point to the word "consider" in the book which shows how easy it is to hide behind words in a book when confronted with a unsatisfactory situation in reality.
Jesus. Whatever happened to Airmans.... Oh Bollox! I nearly said it again!
EVERYONE should know that if the field elevation is 5300 feet you absolutely must , repeat must, switch on the landing lights at exactly 15300 feet, corrected of course for cold temperature, low QNH and moon's gravitational pull. The consequences of switching them on at some other altitude are dire in the extreme. If you do it at 15400 feet the lights will burn out prematurely - maybe as soon as after 100,000 hours of such abuse - and if everyone was this lax the company would soon be bankrupt because of the landing light replacement costs. And if you switch them on at 15200 feet you run the risk of bird strike, because we all know that there are birds out there which routinely fly at 9950 feet above the nearest airfield elevation.
Not to mention the public flogging (that you so richly deserve for being such a recalcitrant) being administered by an irate check Captain for failing to fly to essential tolerances. In fact deviating from the required action at 15300 feet could seriously impair your command progression.
Last edited by Mach E Avelli; 15th May 2013 at 04:18.
Like most questions on here there is no definite answer but a lot of things to think about. My last flying job was A320 s out of Denver which is 5280 Msl. As I remember we put the lights on at 10000 msl because of the lights need to extend and although it was not a restriction having them out above 250 kias was not recommended.