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View Full Version : low level lights or photo luminesant lights?


ccsafetymad
21st Dec 2009, 11:10
sorry if my spelling is bad im cc lol..:ugh:
But do you think the actual lights on the floor of the aircraft are better. Or do you prefer the new ones that airlines seem to be putting in, that glow and dont light up?
e.g. older aircraft types tend to have the little christmas tree lights on the floor for emergency
Or do you prefer the newer ones that charge from the cabin lights and glow but only when its dark?
do you think this is an easy way out to save money and time. e.g installing, maintenence etc..
personally i prefered the lights as the photo luminesant ones didnt seem to glow for long or very bright, and what good is that in a smoke filled cabin??.. let me know your thoughts if u know what im going on about..

northern-light
29th Dec 2009, 00:32
Personally I don't see any benefits with the fluorescent lights you are talking about! I'm not even sure it would be approved as an alternative to the standard emergency lights... Lets imagine that its a night flight, and lights have been dimmed for takeoff... they wouldn't shine much in case there was an emergency! Lets hope it hasn't come to the point where airlines choose a second rate option when it comes to safety!

dhc83driver
29th Dec 2009, 08:47
I`ve been flying working on two different types of aircraft fitted with photo luminescent lights for many years and i have found them to be very good. They are not your typical `toy` glow in the dark type but a very efficient modern material. They require only 15mins of normal light levels eg cabin lights on or daylight to charge them up and they Emmit a very strong green light for many hours. This can be seen when powering down the aircraft in darkness when the cabin is lit up in a green glow. In an emergency with smoke they give a very clear indication of where to go with arrows that are clearly visible. On my current type they are supplemented by ceiling mounted emergency lights and lit exits. These strips last longer and require no maintenance. Other aircraft i have flown with LED type whites and reds give only indication and no light. Both are good in there own way and give the required guidance in an emergency. Nothing to be concerned about on a safety point of view.

nnc0
2nd Jan 2010, 03:05
I was here pondering if this was the forum to enquire professionally about Post Traumatic Stress suffered by cabin crew following in flight incidents such as a depress'n when this thread caught my eye. Having worked in a number of aviation design capacities I now work in a safety of flight capacity and have done some work concerning photluminescent strips.

DHC83driver offerred a favourable impression of the strips and that is entirely possible. I would be careful taking those thoughts as applicable for every case though. Either the cabin crew he works with have been following he AFM supplement and the MANUAL for CONTINUAL AIRWORTHINESS to the T, or he's referring to DHC8's which fortunately provide much more natural light exposure than a 320 or 737 simply because of the fuselage design and cabin configuration.

The reality is that if you're interested in evacuating passengers in the dark or from a smoke filled cabin, the photoluminescent strips are almost useless if not properly charged at the beginning of the day. (The sales guys don't tell that to the engineers and the engineers are so enamoured by the weight savings and the reliabilty improvement that they don't really investigate the issue too thoroughly.)

If you don't know how or what it means to charge the strips then shut down all the cabin lights after the last flight of the day or try it in the Cabin Sim, and have a look at them in the dark. Then ask yourself if they provide enough luminescence to guide people to safety. If you're not charging the strips properly, which most operators are not, then I suspect your next thought will be something like "Jeeeezus". Then I bet you ask - OK how do I charge them properly.

Simply leaving the cabin lights on full bright between or during flights isn't enough. I can refresh myself on the specific requirements if there's any inteest but from what I recall - at the very least, if the aircraft is powered down ovenight, then you need a 15-30 minute charge before the first aircraft flight of at full bright with no pax on board and ovrhd bin doors closed to charge the lights properly. Anything less will result in performance that would not meet min certification requirements.

dhc83driver
2nd Jan 2010, 10:45
Aircraft i`ve operated, DHC8-300, this had LED type floor lights. Avro RJ. Photo luminescent strips. NO charge needed. used the emergency lights to operate the strips. (floor and edge of seats). Strips were replaced on a time expired system by engineers to ensure they met the suitable performance. current aircraft EMB170/190. Modern new aircraft with modern system. Requires a charge of only 15 mins in normal light levels. Modern materials are very good. They have a half life of about 8 years and are not effected by extreme heat or cold or give out electromagnetic of radiated frequency interference like the older strips found on older aircraft. I guess its all about knowing what you are working with and its limitations and having a full understanding of all equipment.

greatwhitehunter
2nd Jan 2010, 10:54
speaking as an engineer who has to maintain these systems i feel you are better off with the electrolumiinescent strips. All to often the battery powered systems have their power supplies disrupted and only partially work. as to lighting levels the strips must meet the required standards to be certified for fitment to an aircraft.

girtbar
2nd Jan 2010, 13:06
The strips do look cheap and low tech compared to a row of lovely little LED lights, but they are deceptively more useful IMOP.

The lights work great if like greatwhitehunter points out your power source is still available, your a/c is in one piece and its a "straight" forward evac.

These little strips will still be shinning brightly even if the cabin floor has been deformed or broken. Something that will be very useful if you add smoke to that set up!

Otto Throttle
2nd Jan 2010, 18:52
The strips on the E170/190 are indeed superbly bright. It's not very often that we cannot hand the a/c off to an engineer at the end of the night, but when we do occassionally have to shut it down, the strips are incredibly bright. And that is after having been charged by cabin lighting only.

Even returning the next morning, after a 7 hour plus lay up in the dark, the strips are still clearly visible, but I'm not sure at that stage they would be sufficiently bright for a smoke-filled cabin. However, they will charge as advertised in 15 mins.

Happy days. :ok:

nnc0
2nd Jan 2010, 19:08
The EMBs were certified with the strips incorporated into the basic design and they're part of the certification package of the aircraft. On any other aircraft out there the strips are retrofitted STC installations. The most noticeable difference is the width of the material. The strips installed via STC are narrower.

The strips perform adequately on the EMBs without any real precharging requrements due to the narrow fuselage and the 2 abreat seating. I think the windows are also a bit bigger in comparisson to a 320 or 737 and let in more natural light. You won't get anywhere near the the same luminescence though on a 320 or a 737 without the precharging.