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

[Bearcat F8F]

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?

[bvcu]

TCAS .......?

[iflytb20]

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.

[excrab]

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.

[sevenstrokeroll]

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.

[737-NG]

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)

[TURIN]

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)

[Bearcat F8F]

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...

[Denti]

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.

[zondaracer]

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.

[Bearcat F8F]

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).

[Capt Claret]

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:

[misd-agin]

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:

[de facto]

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:

[Wizofoz]

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.

[Capn Bloggs]

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:

[Tee Emm]

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:

[MarkerInbound]

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.

[Capn Bloggs]

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! :=

[mustafagander]

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.

[merch]

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.

[captjns]

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.

[misd-agin]

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'.

[727gm]

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.

[Lookleft]

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.

[HAWK21M]

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.

[B772]

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

[autoflight]

They had them because the B52 did.

[stilton]

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

[Trent 972]

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.

[InSoMnIaC]

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

To save Newspaper ;)

[Linktrained]

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

[svhar]

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.

[Checkboard]

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.

[vaffangool]

Yes right back in the days Celestian [sic] navigation was done with the help of stars using sextants....I think no company still makes sextants, even though some nostalgics still might use them...

Astronavigation instruments remain under continuous manufacture. Among the highest-quality instruments are those of Tamaya, whose products embody Japanese reliability and precision; and Cassens & Plath, whose sextants pair German optics with old-world craftsmanship. Top-of-the-line models command prices in the neighbourhood of $2,000.

The most affordable metal (bronze arc, aluminium body) sextants, such as the Astra III, fetch $800-$900 new. The Davis Instruments Mark 25 is remarkably accurate for a plastic instrument, and at about $250 sets the standard for beginners' sextants.

[criticalmass]

Tamaya and Cassens & Plath are indeed still making excellent sextants (I have a Tamaya Jupiter) and the Chinese-made Astra 3B is a fine instrument at a very reasonable price although the optics in the telesope don't match those of the German or Japanese units. Mechanically you can't fault them.

The other German manufacturer was C. Plath of Hamburg, a separate company to Cassens & Plath. For a number of years I owned and used a C. Plath Navistar Classic, one of their top models. A brief history of the C. Plath company follows (taken verbatim from the Nautical Antiques website operated by master mariner Joel Jacobs, from whom I bought my Tamaya Jupiter.)

quote:-

"C. PLATH COMPANY HISTORY: In brief, Carl Plath started manufacturing sextants, in addition to other nautical products, in Hamburg Germany in 1862 though the purchase of the David Filby instrument company though the company's origin dates back to 1837.

As a result WW II, C.Plath was dismantled completely by the occupation forces. Around 1950, various prohibitions were lifted, and C. Plath was allowed to begin production again of sextants and other nautical instruments. Also in 1949,C.Plath was offered a gyrocompass patent and in 1951 the first gyrocompass designed to this patent was presented to the public. C.Plath progressed from the role of instrument maker to that of a modern marine navigation equipment manufacturer. In the following years the product range was expanded by many more modern designs such as autopilots, speed logs, radio direction finders, etc.

In 1962 C.Plath was acquired by Litton Industries, a large American concern.The C.Plath North American Division was set up in 1978 in College Park near Washington. 1996 saw the introduction of the world's first fiber-optic solid-state gyrocompass by C.Plath. The first ever gyrocompass with no moving parts.

Sperry Marine was formed in 1997 with the combination of C.Plath, Decca Marine and Sperry Marine with more organizational changes yet to come. After 163 years, C.Plath changes its name to Sperry Marine in May 2000. In 2001 Sperry Marine becomes part of the Northrop Grumman Corporation.

In the 1990's Plath came out with a series of new sextant designs with overlapping designs and confusing names. They seemed to have lost their way. Shortly thereafter, C. Plath quit producing sextants. The parent company has completely liquidated everything including machinery, equipment and spare parts."

Unquote.

[Crandons]

and European pilots, at least, wouldn't know a circling approach if it ran over them

Not strictly true Checkboard as I can think of a number of circling approaches that my Airline (large UK holiday company)flies. Including CMF, SMI, CFU, DBK and POP to name just some. Indeed in the summer months we always always try for a visual approach.

Alas, it is becoming harder and harder due to onerous ATC procedures (especially in the Greek islands). Eyebrow windows would make some of these visuals a little easier. There is nothing more satisfying and enjoyable than flying a good visual approach.

[matkat]

Maintenance costs, I was the engineering manager for a B737 operator and this was the only reason that I was made aware off.

[bugged on the right]

Not needed any more. Because pilots can no longer carry out visual approaches, there is no need to keep a runway in sight during a turn.

[blind pew]

The eyebrow windows on the DC9 saved a midair collision on short finals during a circling approach....
Number 2 cut the corner and was descending upon number one...FO in number 1 glanced up and saw belly of DC9-51 filling the window....pushed stick forward (below 500 agl)....
Trainee in tower....
Knew all the crew...skipper in number 2 wasn't the brightest and one of the few I threatened not to fly with (5 years later had an incident with him in the DC10)...before CRM and one of those with a bully boy mentality.

[rogerg]

European pilots, at least, wouldn't know a circling approach if it ran over them
I have done quite a few, BHX being one, We still teach them during the MCC.

[Skyjob]

European pilots, at least, wouldn't know a circling approach if it ran over them
In our network of 737 operations various destinations have "only" got circling approaches to one runway end. Thus the manoeuvre is trained in simulator every 6 months.
I have done quite a few, BHX being one
BHX is surely not fond of them as to the North and West is a dense built up area, very noise sensitive, the terminal built up area is located to its East, only sparsely populated ground to its South, but with expensive villages, so far from ideal in a jet.

[aterpster]

Iflytb20:

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.

The 707 had a tube in the aft ceiling of the cockpit that could be opened and have a sextant inserted.

[Evanelpus]

Why has Boeing painted over the 2 little upward-facing windows on each side of the cockpit?

I rather hope they did more than just 'paint' over them.:rolleyes:

[LeadSled]

Folks,
The real answer is really quite simple --- the forward fuselage of the KC-135, B707, B727 and (at least) early B737 were common, (and the eyebrow windows were a Mil Spec. requirement) all out of the same jigs.
There was never a FAR 25 requirement for the eyebrow windows - that was an excuse for an answer from somebody who didn't know, but would not admit they didn't know.
Source - Boeing in briefings in Seattle.
Said eyebrow windows in a B707 were not used by navigators, the aircraft had a port for a periscopic sextant. The most common one, apparently widely used by both military and civil operators, was made by Kollsman. Even at piston speed, the hand held sextants (still bubble) did not produce easy results.
Unlike competent navigators, some of my efforts at doing a star fix produced results that excited much mirth from the rest of the crew.


http://www.prc68.com/I/S5807.shtml

[silverstrata]

Ledsled

The real answer is really quite simple --- the forward fuselage of the KC-135, B707, B727 and (at least) early B737 were common, (and the eyebrow windows were a Mil Spec. requirement) all out of the same jigs.


But why did the military want them?

I don't buy the idea that they were for visual manoevering, because some twit made them curved to fit the fuselage. So they are lenses, and therefore impossible for doing visuals.

When I first jumped into a 737 I thought they would be great. But as soon as I looked out through 4 & 5 the airfield disappeared into the distant horizon. Utterly impossible to do visuals with them.

Thing that gets me, is that a team of skilled artisans have been diligently making these complex windows for 50 years, and nobody has ever used them. They would have had more productive lives on a pension, sunning themselves on a Hawaiian beach.

[Denti]

Why would a curved window have to be a lens? There are more than enough airliners flying around with curved windows, like the 747, 787 to name some boeing variants.

I found the eyebrow windows quite helpful when doing a visual to the opposite side. Granted, the field of view wasn't great, but it was better than without them. Always wondered how boeing could get away with so tiny main windows in the first place.

[Capn Bloggs]

and therefore impossible for doing visuals.

No they are not. They are quite helpful when turning base during the initial part of the turn.

[stilton]

Agree, they are very useful, if you are on the 'high side' looking into the turn maneuvering to final you couldn't ask for more.


It is a very limited application but useful nonetheless, rest of the time they were a pain !!

[belowMDA]

I'll chime in to add that I too found them helpful when conducting visual approaches, especially those with a close in turn to finals and the runway was out the other pilots side.
When our 737-300s had theirs removed, they replaced them with just an uninsulated blank. So if you had a reasonable time in the cruise it was akin to having an open freezer just above your head. In the end they required more paper stuffed up them than the original windows! :ugh:

[Eric van der Veen]

But these [Tamaya etc.] are maritime sextants. Useless on an aircraft.

Aircraft sextant are not in production anymore, anywhere. All there is are leftovers from WWII and into the '60s.

[Geriaviator]

Sunglasses ... I found these essential when above cloud, even though FL120 was my lot as both machine and driver were normally aspirated. My problem was the glare reflected upwards from the cloud as well as the direct rays. I wouldn't go without my trusty pair of polarised which filter out all but horizontal rays.

Many years later I found that UV rays can cause cataracts, when the eye lens becomes clouded and hardens. UV radiation is more intense at altitude and like X-rays has a totaliser effect: the exposure clock goes on ticking once you start, and you can't wind it back.

Today I have a nice pair of plastic lens implants as well as sundry other replacement parts, but I suggest the original components are better. Of course I'm only telling you what I myself was told about such things over half a century ago, but paid little heed :ouch:

[Denti]

I flew quite a long time without sunglasses, but as i grew older i noticed that i could cope less and less with the glare, especially in or close to clouds. So i second that opinion. However, polarized glasses are a very bad idea in a glass cockpit airplane, better check them out before finding out that all those nice screens are now black, or only half of them show anything useful.

And of course a regular yearly check at your friendly ophthalmologist is not a bad idea either.

[Geriaviator]

Quite so, Denti, I found that my scrip polarising glasses pretty well block digital display in my cars. There were no glass cockpits in my flying days, my No 2 TX/nav still had valves!

The 1970 issue Service flying helmet had a tinted visor with a clear section across its base so the user could see instruments etc. It might be possible to order a similar design in glasses, like bifocals.

The annual C of A with your optician is really essential as you say. He/she can often spot something going wrong as the birthdays fly by at mach 2 :eek:

[yeoman]

As below MDA says, the straight blanks were a pain. They got very cold in the cruise and developed a layer of ice crystals from exhaled water vapour.

This would then melt in the descent and the now liquid water would drip with laser like accuracy into the crotch. A walk through the terminal a little later with a wet crotch was always a great end to the day:E

[A Squared]

.... because some twit made them curved to fit the fuselage. So they are lenses, and therefore impossible for doing visuals..

reeeeallly ??? a curved window is a lens and useless????. There's probably only been a very few automobiles models manufactured during your lifetime which *didn't* have curved windshields (The VW Beetle and the Jeep CJ series are the only ones I can think of off the top of my hear) So, chances are good that at some point you have driven a car with a curved window. Did you roll down your window and stick your head out while driving to avoid the lens distortion?

[Jwscud]

The more highly curved windshields of aircraft are a bit of a problem.

On the Learjet, the windshield has a strong curve, and no wipers, simply relying on airflow and coating to keep the view clear. At night even in clear weather you get a very disconcerting effect of the real runway lights and an angled reflected image. In heavy rain and not aligned with the runway it's a real bugger.

[Metro man]

Speaking of curvature, I have two pairs of glasses with progressive lenses.

One pair is curved, slightly wrap around style which is fine during daytime but I find the runway and approach lights distorted at night, particularly if they are very bright.

The other pair have relatively flat lenses and have hardly any distortion at all.

[vapilot2004]

However, polarized glasses are a very bad idea in a glass cockpit airplane, better check them out before finding out that all those nice screens are now black, or only half of them show anything useful.

I always buy polarized sunglasses for everyday use outdoors, particularly around the water, and while I am not advocating polarized lenses in the cockpit, I can say tilting one's head usually brings lost screens 'back to life', although displays that were fully viewable prior to the 'adjustment' become dark.