Something I've been curious about for a long time.

Why has Boeing painted over the 2 little upward-facing windows on each side of the cockpit? I assume they've done this with the introduction of the NG? Although I have a feeling there are some older 737s kicking about without these windows...

As far as I can see, there are no instruments/ gauges etc there now, so why take away some visibility?

TCAS .......?

IIRC they were used in the 707/727 days for taking star sights. Since the 737 shares the same fuselage, the eyebrow windows got carried forward. I remember reading an article from Boeing which said they were deleted to reduce the cockpit noise levels. Aircraft without the eyebrow windows are also equipped with 10 vortex generators just forward of the main windows. Boeing claimed a ~3 dB (not sure of the value) reduction in noise and appx 10000 $ per year reduction in mx costs. They offer kits for the older acft to remove the windows and install a plug in their places.

Please feel free to correct me :ok:

Cheers

PS : I believe they deleted the window in the NGs from mid 2005 onwards.

iflytb20 is correct, although they are still available as an option on new build aircraft. Supposedly useful on military versions for refuelling.

Not having them saves scratching around for newspapers / magazines / paper towels to stuff up there in order to keep the sun out.

I prefer the ''eyebrow" windows...had them on the DC9 and the earlier 737's.

I don't think they were for star sights...a navigator astrodome would have been more appropriate.

They provide more light in the cockpit during the day, aid keeping things in sight during banks.

Yes right back in the days Celestian navigation was done with the help of stars using sextants whether by air or sea navigators. So planes, especially bombers in the second world war had those big windows on the top to allow for a better sighting of the stars.
Today with all available navaids, then inertial nav systems, then now satellite navigation,it has pretty much disappeared. I think no company still makes sextants, even though some nostalgics still might use them ( I heard it is quite a difficult way to navigate)

Been discussed a few times on Pprune.

This seems to be the most accurate.

B737 no.4 and 5 windows (http://www.pprune.org/engineers-technicians/368034-b737-numbers-4-5-windows.html)

Thanks for the replies.

Still seems strange to me - didn't think sun glare is an issue as pilots can and usually do wear sun glasses. And I would've thought any extra visibility would be welcome - especially when turning.

Why would removing the windows affect the installation of vortex generators and/or a reduction in noise...

The windows are unrelated to the vortex generators, they were just introduced around the same point in time. Main reason cited in my company was 300 man hours less maintenance per year and airframe which is a considerable amount of money.

Personally i prefer them, especially during circling and visual approaches because they make it easier to keep stuff in sight, however in "my" outfit all planes are delivered without those windows and old planes are retrofitted with a metal plug. Weird thing is, even new planes still had the window shades up there for those never installed windows until last or year or so, just wonder if boeing charged for them.

By the way, i haven't worn sunglassed in the last 10 years or so, works out fine usually, especially in newer planes with those roll-out shades that cover nearly the whole window.

The FAA used to also have a minimum window area for the cockpit for certification, so adding those eyebrow windows helped meet the requirement. That requirement is now history so Boeing doesn't include the eyebrow windows anymore as standard.

Very interesting! Thanks for the replies fellas!

Denti, for some reason I also opt to not wear sun glasses (although my experience is no comparison to yours...yet).

My understanding is the same as zondaracer. Most of our fleet of Douglas/Boeing 717 have them. They're a pain in the butt due to glare and sunburn on bald pate's.

All have been fitted with Alfies, which are reflective aluminium foil screens, cut to size & shape, to block them. As it happens I'll be meeting with Alf, the pilot designer, later this morning. :ok:

MORE LIGHT in the cockpit? :eek:

Keeping things in sight while banked? When can you use the eyebrow windows during turns??? Above 60, or more, degrees of bank??? :ugh:

Having done quite a few visuals and circle to land in NG and Classics,I dont remember using those small windows...unless you like to keep it romantic and watch the stars in the process:E
Good thing they got rid of it in my opinion.
I also opt to not wear sun glasses
Why would that be?protect your eyes and next time you fly a visual and landing into the sun,dont land on the parallel taxiway please:ok:

Looks like they haven't been included on either the p-8 Poseidon nor the Wedge tail AWAC, so even the military don't seem that bothered.

When can you use the eyebrow windows during turns??? Above 60, or more, degrees of bank??? :ugh:
Instead of gawking at your ND, next time you do a circuit/visual traffic pattern/circling approach (at 20°AOB), have a look across the cockpit about half way round the base turn. You will find the runway threshold right where the eyebrow windows are/used to be.

They are very handy for that, but since circling approaches are now "on the out", cheaper to fill them in (as well as keeping shiny pates like Claret's sun-free).

Say hello to Alf for me! :ok:

but since circling approaches are now "on the out",

If circling approaches are now considered "dangerous" in jet transports why aren't they banned for life in small aircraft. After all, same principle.:ok:

Ah, because if you're using category A minimums you're still in the airport?

In FAA land commercial operations are held to a higher standard. If you're flying yourself around you (should) understand the risks of zero-zero takeoffs or circling approaches. SLF just put their money down but don't really understand what they are getting into so the FAA is tasked to look out for them.

If circling approaches are now considered "dangerous" in jet transports why aren't they banned for life in small aircraft.
Your word, not mine. Also, bugsmashers are half the speed, at least twice as manoeuvrable, and the pilots thereof can probably actually fly their aeroplane, as opposed to the standard jet jock these days who goes into a major decline if taken off the magneta line. :}

Get back on thread, Bloggs! :=

Just to put to bed an error, astro nav shots were NEVER taken through the eyebrow windows ever.

For starters the transparency has heaps of distortion. How would a nav get into position for his shot? The sextant they used was a periscopic model by Kollsman (I think) and was fitted to a roof mount just behind the FE on the aircraft centreline. I watched many a fix reduced over the years I was on B707s.

737-NG
"I think no company still makes sextants, even though some nostalgics still might use them ( I heard it is quite a difficult way to navigate)"

Ships are still required to carry sextants, and are used to practice the "art", just in case GPS is not available for some reason, failure of the receiver(s) plus it's not good practice to relay on only one method of position fixing.
Tamaya and Plath at least still manufacture them.

The eyebrows made an ugly duckling just a homely duckling. Loved them on my good old reliable 727 and 737-100 and 200. Good spot for the GPS suction cup too:ok:. Never missed breakfast or last call for happy hour.:E


I put paper cut out of sky scenes in the wells where the eyebrows used to be. Need to keep the nostalgia going.

CatpnBlogs - how about figuring a spot 2 or 3 miles on final and using that as a roll out point? Doesn't require rotating your head 90 degrees, and up, to look through a small window.

I've used that technique many times when the runway is on the 'wrong' side. Runway is X. Pick a spot 2-3x on final and base you turn off of that. Building, road, field, etc. Pick something, fly over it. Sporting when you're at 30 degrees of bank, 1000' FPM, and can't see the runway. :ok:

Did that years ago into XXX. A week later talking with the mechanic and he was talking about the crazy approach he'd seen. Crazy? 100% within SOP. After years of watching 10 mile straight-in's he wasn't prepared to see a fairly tight visual pattern.




Removing the eyebrow windows impact on the noise in the cockpit? It dropped from 'too loud' to 'still too loud'.

Loved them: The eyebrow windows were wonderful for circle-to-lands when the PF is in a seat opposite the direction of turn to base/to final....a (sight)picture's worth a thousand words. e.g. Circle to RNY26 PAJNe.g. Circle to RNY26 PAJN. The eyebrows usually had dark green plastic inserts to keep the sunlight down.

If you have a look at the cockpit window layout of a B-17 there is a certain similarity for the lineage of forward fuselage that started with the 707. The main difference being the pressurisation of the jets. Just MHO. As for being useful in a visual approach, I usually found looking out the main windows or asking my cockpit colleague "howgozit" worked better than looking for a threshold out of windows 4 and 5.

Ships are still required to carry sextants, and are used to practice the "art", just in case GPS is not available for some reason, failure of the receiver(s) plus it's not good practice to relay on only one method of position fixing.
Tamaya and Plath at least still manufacture them.

Amusing anecdote (reportedly true!): I know of a crusty old British Merchant Marine captain who believed in staying current with the old techniques. His ship (mid Atlantic at the time) was approached by a US Navy cruiser, and they shouted across the water asking for a position fix. They'd suffered a ship-wide power outage and consequently were 'lost' (no GPS in those days, but INS was the norm).

Apparently he made a show of fetching out his sextant, taking a few tedious measurements and repaired to the bridge for some sums and swift refreshment. He then came back out on to the bridge wing with a loud hailer and shouted the position to them!

With Technology,the purpose was defeated,then stores inventory would reduce due to not needing to replace the Windows & WHCU malfunctions.A reduction in noise too.

I remember reading an article by Boeing many years ago saying the windows were removed to reduce weight and lower the production cost.

They had them because the B52 did.

Join Date: Mar 2006
Location: california, usa
Posts: 58

'Loved them: The eyebrow windows were wonderful for circle-to-lands when the PF is in a seat opposite the direction of turn to base/to final....a (sight)picture's worth a thousand words. '



Could not agree more, they were very useful on the lovely B727.



They seem an odd ommision on military 737's

Boeing Next-Generation 737 Gets a Face-Lift (http://www.boeing.com/news/releases/2005/photorelease/q1/pr_050126h.html)


SEATTLE, Jan. 26, 2005 -- Boeing [NYSE:BA] this week rolled out its first 737 without eyebrow windows, the four small windows above the front windshield. In the past the eyebrow windows helped provide better crew visibility, but today's advanced navigation systems have made those windows obsolete. The design change reduces airplane weight by 20 pounds and eliminates approximately 300 hours of periodic inspections per airplane. Retrofit kits to cover eyebrow windows will be available mid-2006 for the in-service 737 fleet.

Why did Boeing get rid of top cockpit windows in the 737?

To save Newspaper ;)

Astrodomes were fitted to earlier aircraft and were calibrated. The lower parts, near to the fuselage, had some distortion and one aimed to avoid using lower altitude stars etc. (Each minute of distortion would displace a position line by one nm.)

Initially pressurised aircraft ( DC6 vintage ?) had Astrodomes. I heard that one lost its Navigator and for a while N/O would use a "monkey chain" to prevent this happening. Periscopic sextants (Hughes or Kollsman?) were put through a special hole in the roof - too small to lose any N/O ! But they did require precomputing because you got a small field of view of the sky, using precomputed tables. It was sometimes possible to obtain a series of Sun/Moon/Venus fixes and in broad daylight too - professionally very satisfying.

LT

To me, these windows always were totally pointless. Always covered with a scratched sunscreen and/or newspapers. One instructor once told me that they were there because some regulations stipulated minimum accumulated square inches of windows in a cockpit. I am not trying to sell the idea, but it sounds plausible. The DC-8 and DC-9 had these eyebrow windows too. A little larger than in the Boeings but totally useless as well. These regulations may have been thrown away, but all the later models do have larger windows.

There has never been a regulation for area of cockpit glass.
They were never included for astro-navigation.
They were never included because "the 707 used to do in-flight refuelling"

:rolleyes:

They have always been there for visual circling (left pilot uses the right windows in a right turn and vice versa). As 99% of operations are now ILS to ILS, and European pilots, at least, wouldn't know a circling approach if it ran over them, and simulator projection screens never extended high enough to include the eyebrow windows (so those who only manoeuvred in the simulator never saw how useful they were), the "cost-benefit" ratio has been deemed excessive.