April 8, 201610 yr They don't need taxi lights David because the Captain instructs the FO to lean out the window with his High beam torch to taxi, although he might find this difficult on landing though I7-8700k,Corsair h1101 cooler ,Asus Strix Gaming Intel Z370 S11 motherboard, Corsair 32gb ramDD4,, gtx 1080ti Card, RM850 power supply Peter kelberg
April 8, 201610 yr I've never heard of BA not having tax lights? This looks like taxi lights to me. Do they just turn on runway turnoff lights instead of taxi lights? Outboard landing lights usually, IIRC. Simon Kelsey
April 8, 201610 yr Author They don't need taxi lights David because the Captain instructs the FO to lean out the window with his High beam torch to taxi, although he might find this difficult on landing though That explains this... http://aviation-safety.net/database/record.php?id=20131222-0 -David Lee
April 8, 201610 yr However, even though I don't know how the lights are exactly, I'd find it hard to believe that there was just ONE bulb per nav light. There must be redundacy so as if just one bulb fails, you still got a green functional light. Most larger aircraft do have two lamps per Nav light assembly. In some installations, both lamps are illuminated whenever the Nav light switch is "on", in others, like Embraers, and Airbuses, the two lamps are on two separate circuits - controlled by a switch on a maintenance panel in the cockpit. Only one lamp is "on" at a time. If one burns out, flipping the switch will bring the alternate circuit into play, lighting the backup lamp. Keeping the lamps off in daytime is probably not so much as matter of saving money on lamp replacement - incandescent Nav lamps are not very costly (in aviation terms at least) - but a matter of dispatch reliability. A burned out Nav light is a complete show-stopper if an aircraft is scheduled to fly during hours of darkness. It cannot be dispatched with an inoperative Nav light. Depending on the specific aircraft model, replacing Nav lights may not be a simple or quick process. On the business jets I work on, the aerodynamic fairing that covers the lamps has polysulfide sealant around its entire mating surface, and that is the problem. Replacing the lamps themselves may not take long, but after the fairing is reinstalled, new sealant has to be mixed and applied - and that sealant can take up to 12 hours to cure sufficiently so that the aircraft can be flown. Without the sealant, if the aircraft flies through any precipitation, water can easily get into the inside of the fairing, and if even a small drop touches the hot lamp, it will crack. Many new aircraft have LED Nav lights. Those do have a much longer life than incandescent bulbs, but they do eventually wear out too. Their light output will diminish with age. With LEDs, costs ARE a factor. An incandescent aircraft Nav lamp might cost only $15 or $20 - but a replacement LED light assembly might easily cost upwards of $4000. Jim BarrettLicensed Airframe & Powerplant Mechanic, Avionics, Electrical & Air Data Systems Specialist. Qualified on: Falcon 900, CRJ-200, Dornier 328-100, Hawker 850XP and 1000, Lear 35, 45, 55 and 60, Gulfstream IV and 550, Embraer 135, Beech Premiere and 400A, MD-80.
April 8, 201610 yr I believe another reason was the sun glare through the "eyebrow" windows. Those windows were more annoying than anything else, pilots were always covering them with charts or newspapers. Interesting! Do these 737 have a non-functioning LOGO lights switch in the overhead? No, they didn't install the switches on those planes. Tom Landry
April 8, 201610 yr Most larger aircraft do have two lamps per Nav light assembly. In some installations, both lamps are illuminated whenever the Nav light switch is "on", in others, like Embraers, and Airbuses, the two lamps are on two separate circuits - controlled by a switch on a maintenance panel in the cockpit. Only one lamp is "on" at a time. If one burns out, flipping the switch will bring the alternate circuit into play, lighting the backup lamp. Keeping the lamps off in daytime is probably not so much as matter of saving money on lamp replacement - incandescent Nav lamps are not very costly (in aviation terms at least) - but a matter of dispatch reliability. A burned out Nav light is a complete show-stopper if an aircraft is scheduled to fly during hours of darkness. It cannot be dispatched with an inoperative Nav light. Depending on the specific aircraft model, replacing Nav lights may not be a simple or quick process. On the business jets I work on, the aerodynamic fairing that covers the lamps has polysulfide sealant around its entire mating surface, and that is the problem. Replacing the lamps themselves may not take long, but after the fairing is reinstalled, new sealant has to be mixed and applied - and that sealant can take up to 12 hours to cure sufficiently so that the aircraft can be flown. Without the sealant, if the aircraft flies through any precipitation, water can easily get into the inside of the fairing, and if even a small drop touches the hot lamp, it will crack. Many new aircraft have LED Nav lights. Those do have a much longer life than incandescent bulbs, but they do eventually wear out too. Their light output will diminish with age. With LEDs, costs ARE a factor. An incandescent aircraft Nav lamp might cost only $15 or $20 - but a replacement LED light assembly might easily cost upwards of $4000. No, they didn't install the switches on those planes. Thanks Tom! And thanks Jim for your elaborate response from a mechanic's point of view, very much appreciated! Jaime Beneyto My real life aviation and flight simulation videos [English and Spanish] System: i9 9900k OC 5.0 GHz | RTX 2080 Super | 32GB DDR4 3200MHz | Asus Z390-F
April 8, 201610 yr As mentioned above, nobody said it was about saving fuel. My bad. I misread somebody's post on page one... They were talking about Iberia.In a previous life, my job was to save fuel/time for BA (well British Regional/CitiExpress) on a daily basis. We would work on a rough rate of 145gbp a minute, that the plane wasn't sat on the floor, and that was 10 years ago.They stripped all the APU's out of the Dash 8's to save money, so I'm not surprised that they are now onto lightbulbs....Lets be honest, we could close off lavatory's, stop using APU's on all aircraft, and even go to the extreme of flying on one engine.... Just because we have two doesn't actually mean you have to use it do you? Trip 7 can be certified for what, 300 mins of flight on one engine. there is a maths equation in there somewhere between drag, weight, increased fuel et al for someone far cleverer than I!and yes, its an absurd suggestion...Liam "I forgot my name" Reynolds Liam Reynolds - EGNS Youtube Channel
April 8, 201610 yr Author My bad. I misread somebody's post on page one... They were talking about Iberia. In a previous life, my job was to save fuel/time for BA (well British Regional/CitiExpress) on a daily basis. We would work on a rough rate of 145gbp a minute, that the plane wasn't sat on the floor, and that was 10 years ago. They stripped all the APU's out of the Dash 8's to save money, so I'm not surprised that they are now onto lightbulbs.... Lets be honest, we could close off lavatory's, stop using APU's on all aircraft, and even go to the extreme of flying on one engine.... Just because we have two doesn't actually mean you have to use it do you? Trip 7 can be certified for what, 300 mins of flight on one engine. there is a maths equation in there somewhere between drag, weight, increased fuel et al for someone far cleverer than I! and yes, its an absurd suggestion... Liam "I forgot my name" Reynolds Some Dash 8 -400 operators and other regionals in America do not have running water/toilet or an apu. - David Lee
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