April 5, 201610 yr I mean exactly how much fuel are we talking about here for saving? its cant be that much can it??? Exactly. And now go ask yourself how much fuel the In-Flight Entertainment system consumes. I think it's outright stupid to pretend to save some money by turning the NAV's off. 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 5, 201610 yr Thanks. I thought so. Why does the FAA mention, in paragraph e, "navigation and position", as if they were different things? That's inducing confusion. I re read you reply and realise you probably know exactly what they are... but if it helps someone else ill leave the info below! Liam... I was hazard a guess that the Red and green, (akin to port and starboard on a boat) are shown as navigation lights, in fact... (wikipeida https://en.wikipedia.org/wiki/Navigation_light) - Right-of-way lights — A red light is mounted on the left or port side of the craft and a green on the right or starboard side. In a situation where the paths of two watercraft or aircraft cross, these lights help each crew determine the other craft's direction and who has right-of-way. When two craft have crossing paths, each sees a red or green running light. The craft on the port side, which must yield right of way, sees the red light on the other, while the craft on the starboard side, which has right of way, sees the green on the other. Where as position lights show your position (same web page as above) - Aircraft navigation lights are placed in a way similar to that of marine vessels, with a red navigation light located on the left wingtip leading edge and a green light on the right wingtip leading edge. A white navigation light is as far aft as possible on the tail or each wing tip.[3] High-intensity strobe lights are located on the aircraft to aid in collision avoidance. It goes on from there... Liam Reynolds Liam Reynolds - EGNS Youtube Channel
April 5, 201610 yr I mean exactly how much fuel are we talking about here for saving? its cant be that much can it??? On the whole, it's not about fuel saving, it's about bulb saving. (And also the general principle that if you're not using/don't require a system, you should switch it off). For types with retractable landing lights there is a small fuel burn penalty due to the aerodynamic drag, and if you look in the MEL for a type with retracts you will likely find a fuel burn factor for flights dispatched with lights stuck in the extended position, but it's small enough that I suspect even the most voracious fuel saving airlines aren't bothered about it in the normal course of operations. As a general principle, however, it's important to remember that even a fuel saving that seems negligible on an individual flight adds up very quickly for an airline that could be operating thousands of sectors every day. If, for instance, you could save 2kg per flight by adopting a particular measure -- that seems pretty negligible (and wouldn't even show up on the FQIS of most aircraft) for a single flight, but 2kg x 2000 flights per day = 4 tonnes a day, or nearly 1,500 tonnes per year. Exactly. And now go ask yourself how much fuel the In-Flight Entertainment system consumes. I think it's outright stupid to pretend to save some money by turning the NAV's off. On the other hand, you could argue it's pretty wasteful in principle to be burning up bulbs when you don't need to, regardless of the cost. As mentioned above, nobody said it was about saving fuel. Simon Kelsey
April 5, 201610 yr On the other hand, you could argue it's pretty wasteful in principle to be burning up bulbs when you don't need to, regardless of the cost. As mentioned above, nobody said it was about saving fuel. Yes, I'm sorry. That is an argument I would buy. 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. I remember the time when in Spain it was "forbidden" to drive with low beams on during the day. In other countries such as Sweden it was "mandatory" to drive with low beams on all the time. Their cars were even built to turn the low beams on by default. You can imagine what happened when Swedes drove to Spain for a vacation... I personally leave my low beams ON all the time. My reasoning: If there is just one instance in my whole life in which leaving those lights on makes me being seen by another driver who otherwise would not have seen me (for instance, due to sun glare or reflection), then it will have been worth it. I'd say the exact same applies for airplanes. 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 5, 201610 yr I mean exactly how much fuel are we talking about here for saving? its cant be that much can it??? Interesting question. Does anyone know how much electrical power is consumed by each external light of the 777?
April 5, 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. Airliners do have two bulbs for each position. At least all the ones I have flown. The Airbus, well our Airbuses, only have one set turned on at a time, which is annoying because if you find one burned out you have to go back to the cockpit and switch to the other set and go back out to make sure all of those are working. To date I've only ever found the white tail nav lights burned out on the Airbus. I'm guessing it's because that is a regular bulb and the red and green are LEDs. Tom Landry
April 5, 201610 yr Author Exactly. And now go ask yourself how much fuel the In-Flight Entertainment system consumes. I think it's outright stupid to pretend to save some money by turning the NAV's off. American Airlines used to deactivate all their logo lights to save money on bulbs and upkeep. I don't know if they still do. The removal of the eyebrow windows in the ngx was also for money saving reasons. - David Lee
April 7, 201610 yr Right about the time the new livery came out at AA they announced that the logo lights would be reactivated on the planes that had them and all new deliveries would be equipped with them. There is a batch of 737s that never had them installed so those planes will never have logo lights. I have found on the majority of legacy AA Airbuses they are burned out and nobody ever writes them up so they don't get fixed. I have noticed on the majority of legacy US Airbuses the logo lights work. Tom Landry
April 7, 201610 yr The removal of the eyebrow windows in the ngx was also for money saving reasons. 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. There is a batch of 737s that never had them installed so those planes will never have logo lights Interesting! Do these 737 have a non-functioning LOGO lights switch in the overhead? 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 777200lrf, on 05 Apr 2016 - 9:57 PM, said: The removal of the eyebrow windows in the ngx was also for money saving reasons. The removal of eyebrow windows has to do with the onset of Inertial navigation. Therefore making celestial navigation uneccessary (What the eyebrow windows were for) . Super VC10 into LOWI with PF3 at a cinema near you https://www.youtube.com/watch?v=298UDyNmgUA
April 8, 201610 yr Interesting! Do these 737 have a non-functioning LOGO lights switch in the overhead? If they're anything like BA's 747s (delivered without taxi lights) there probably isn't a switch at all. Simon Kelsey
April 8, 201610 yr The removal of eyebrow windows has to do with the onset of Inertial navigation. Therefore making celestial navigation uneccessary (What the eyebrow windows were for) .I don't think you'd have much luck with celestial navigation using the eyebrow windows. They used to use sextant and a dedicated viewing port in the roof giving an all round view of the stars. The eyebrow windows were intended to give a better field of view upwards and in turns but mostly just let too much sunshine into the flightdeck. Removing them saves weight and cost.
April 8, 201610 yr Commercial Member YOU'RE Abe Froman?!? Yeah - that's me. No need to get snooty...or snotty Kyle Rodgers
April 8, 201610 yr Author The pictures of the AA 737 cockpits show no logo light switch was installed 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? In the cockpit they have no taxi light switch. http://www.airliners.net/photo/Oneworld-(British-Airways)/Boeing-747-436/2774467/L/ http://www.airliners.net/photo/British-Airways/Boeing-747-436/2785657/L/ -David Lee
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