Ps76 From , joined Dec 1969, posts, RR: Posted (6 years 4 months 2 weeks 4 days 15 hours ago) and read 5031 times:
Was just wondering what the reason was for the higher windows in the Boeing 737. What would a pilot need to see from the perspective - Maybe for light/general visibilty? Traffic?
CanadianNorth From Canada, joined Aug 2002, 3371 posts, RR: 10 Reply 1, posted (6 years 4 months 2 weeks 4 days 15 hours ago) and read 5036 times:
They are called "eyebrow windows" I believe.
The original nose design of the 737 is basically the same as the 727, which is basically the same as the 707. Back in the day when the 707 was brand new, these windows were useful for spotting traffic, and they also could potentially help with weather, and if things were really bad help with navigation.
However, with todays technology the 737NG can do all that via computer faster, easier and more reliable. Thus, they have been eliminated on 737s currently in production, and it is an option to remove them on 737s made with them.
I find it however funny that the new 737s or old modified 737s which do not have the eyebrow windows don't get my attention, they look somehow normal without them.
Mohavewolfpup From , joined Dec 1969, posts, RR: Reply 5, posted (6 years 4 months 2 weeks 4 days 8 hours ago) and read 4834 times:
how are they a maintenance issue? I think I saw a post in a thread they have maintenance issues. leaky? or just antiqued?
sadly, if I was a pilot I would mourn the loss of being able to see stars out them, but I am really cheesy and like stuff like that.
nothing beats being at 37,000 feet hauling 100+ people to their futures, destinations,marriages,family,vacations,hopes and dreams, etc and looking at stars wizzing by at 500 mph.
okay, i'll cut the sap :p
it also shows how much more reliant we are becoming on computers also to do the work of what pilots had to do in the past manually (finding the north star)
N231YE From , joined Dec 1969, posts, RR: Reply 6, posted (6 years 4 months 2 weeks 4 days 7 hours ago) and read 4822 times:
Quoting Mohavewolfpup (Reply 5): how are they a maintenance issue? I think I saw a post in a thread they have maintenance issues. leaky? or just antiqued?
The eyebrow windows added "unnecessary" weight, and I believe the maintenance issues included lamination problems (?).
N243NW From United States of America, joined Jul 2003, 1494 posts, RR: 21 Reply 7, posted (6 years 4 months 2 weeks 4 days 6 hours ago) and read 4803 times:
Quoting CanadianNorth (Reply 1): Thus, they have been eliminated on 737s currently in production
Quoting CanadianNorth (Reply 1): and it is an option to remove them on 737s made with them
Same story with the 717. Is there an option offered [yet] from Boeing to fill existing windows with this model as well? Or is the demand (fleet size) too small to make such a retrofit cost-effective?
Nonfirm From United States of America, joined Sep 2005, 434 posts, RR: 0 Reply 8, posted (6 years 4 months 2 weeks 4 days 2 hours ago) and read 4763 times:
The removal of the eyebrow windows is very helpful for maintenance.First off there are four less windows that need to be attended to also they have a problem with delamination.If the delam is out of limits then they need to be replaced.I have found with our fleet of 737-400's that almost all of the eyebrow window's are on defferal for delam also with the hud's installed on the Capt's side they are almost useless.As stated most of the time they are blocked anyway with window shade's or paper.
IAHFLYR From United States of America, joined Jun 2005, 4723 posts, RR: 25 Reply 10, posted (6 years 4 months 2 weeks 3 days 20 hours ago) and read 4677 times:
Quoting FredT (Reply 2): Good for keeping an eye on the runway during turns in a visual landing pattern, I'd say
That would sure be a diving turn to keep the runway in sight out the eyebrow windows!
I like the no eyebrow look on the 73's.
Any views shared are strictly my own and do not a represent those of any former employer.
Nonfirm From United States of America, joined Sep 2005, 434 posts, RR: 0 Reply 13, posted (6 years 4 months 2 weeks 3 days 8 hours ago) and read 4546 times:
Quoting Mohavewolfpup (Reply 9): what's the worry with the delam? decompression issues, or just visual issues?
and how are they blocked off? just a metal plate welded in?
The problem with the delam is when it grows beyond the limit from the corners of the window and the sides you are only allowed a few inches if it's beyond then you need to replace the window.Here is the link of the mod.
EssentialPowr From United States of America, joined Sep 2000, 1820 posts, RR: 2 Reply 14, posted (6 years 4 months 2 weeks 3 days 6 hours ago) and read 4515 times:
This all may have been mentioned to some degree, but I will condense it:
- Eyebrow windows were originally installed so a sextant could be used...
- The maintenance bonus comes from the elimination of a heated piece of glass...
- The new structure keeps the cockpit cooler (huge for glass tube a/c), is lighter, stiffer, more fatigue resistant, and completely eliminates a part number.
Good deal all around!
(And if you are a manufacturing guy, the last thing you do is cut out a piece and then weld in a blank...you just eliminate the stamp that cuts out the window in the first place!!!)
2H4 From United States of America, joined Oct 2004, 8950 posts, RR: 62 Reply 15, posted (6 years 4 months 2 weeks 3 days 6 hours ago) and read 4505 times:
AIRLINERS.NET CREW HEAD DATABASE EDITOR
Quoting EssentialPowr (Reply 14): - Eyebrow windows were originally installed so a sextant could be used...
Are you sure about that? If that is indeed the case, why would the VC-137C have had an entirely separate sextant port installed?
EssentialPowr From United States of America, joined Sep 2000, 1820 posts, RR: 2 Reply 16, posted (6 years 4 months 2 weeks 3 days 5 hours ago) and read 4496 times:
B/c a VC 137C uses celestial as a secondary nav to this day... not so the 737, and a dedicated port is not nec in the first place if you've ever used a sexant...an eyebrow window will work, but even from the 707 days Boeing projected that electronic, ground based nav eliminated celestial nav. Old habits die hard in the mil and the Nav in particular...
Forgive me if this has been asked before, but it strikes me that a thick piece of glass would be a better sound insulator than a few mm of sheet metal and a plastic facade.
So does the noise reduction come from that fact that you're losing four panel lines and a row of rivets/bolts?
EssentialPowr From United States of America, joined Sep 2000, 1820 posts, RR: 2 Reply 20, posted (6 years 4 months 2 weeks 2 days 14 hours ago) and read 4365 times:
Quoting BAe146QT (Reply 18):
So does the noise reduction come from that fact that you're losing four panel lines and a row of rivets/bolts?
Absolutely; removal of the window results in a more continuous piece of metal. Any seal b/t a window and the frame will eventually leak somewhat, and therefore hiss, over time...
KELPkid From United States of America, joined Nov 2005, 5932 posts, RR: 4 Reply 21, posted (6 years 4 months 2 weeks 2 days 13 hours ago) and read 4348 times:
Quoting Mohavewolfpup (Reply 9): and how are they blocked off? just a metal plate welded in?
Although it is now possible to weld aluminum (TIG and MIG), I'd put money on the mod being a sheet of aircraft-grade aluminum large enough to cover the hole and then some, placed inside the pressure vessel, and then rivited from the outside. Any mechanics want to comment on this? Also, do the interior panels receive an update at the same time to a part without the window cutouts?
Celebrating the birth of KELPkidJR on August 5, 2009 :-)
ZANL188 From United States of America, joined Oct 2006, 3249 posts, RR: 0 Reply 22, posted (6 years 4 months 2 weeks 2 days 13 hours ago) and read 4336 times:
Quoting EssentialPowr (Reply 16): B/c a VC 137C uses celestial as a secondary nav to this day... not so the 737, and a dedicated port is not nec in the first place if you've ever used a sexant...an eyebrow window will work, but even from the 707 days Boeing projected that electronic, ground based nav eliminated celestial nav. Old habits die hard in the mil and the Nav in particular...
The VC-137Cs are all in museums, modded to another type, or scrapped now so they are certainly not using celestial nav to this day.
So if somebody were to use the eyebrow window with a sextant how would that work exactly? If the pilot stood on the floor the yoke would be poking him in the groin -- I guess he could stand on the seat and do it that way. Just seems awkward to me.
N231YE From , joined Dec 1969, posts, RR: Reply 23, posted (6 years 4 months 2 weeks 2 days 11 hours ago) and read 4289 times:
Quoting EssentialPowr (Reply 20): Absolutely; removal of the window results in a more continuous piece of metal. Any seal b/t a window and the frame will eventually leak somewhat, and therefore hiss, over time...
Since the noise seems to be caused by some sort of disturbance in the airflow, would the removal of the window provide some sort of performance benefit?
EssentialPowr From United States of America, joined Sep 2000, 1820 posts, RR: 2 Reply 24, posted (6 years 4 months 2 weeks 2 days 9 hours ago) and read 4265 times:
Quoting ZANL188 (Reply 22): The VC-137Cs are all in museums, modded to another type, or scrapped now so they are certainly not using celestial nav to this day.
The point is that a lot of mil a/c had them, to include P3s which are still on active service w/ the NAV.
Quoting ZANL188 (Reply 22): So if somebody were to use the eyebrow window with a sextant how would that work exactly? If the pilot stood on the floor the yoke would be poking him in the groin -- I guess he could stand on the seat and do it that way. Just seems awkward to me.
Uhh... remaining seated?
Quoting N231YE (Reply 23): Since the noise seems to be caused by some sort of disturbance in the airflow, would the removal of the window provide some sort of performance benefit?
Absolutely. Aside from the fact that the window is heavier than the blank aluminum that was there in the first place, any time a discontinuity in the a/c's skin is eliminated, the result is smoother airlflow. In short, eliminating the window enhances perfromance by:
1. reducing weight
2. " complexity, as those windows are heated and share a temp controller as well as have requisite wiring/circuit breakers/etc
3. reducing/removing spare parts from the inventory
4. reducing the build cost
5. smoother airflow over the nose section
25 N231YE: I see...I knew about the weight issues for the window itself, but did not realize the associated systems/items and parts inventory. Since nobody uses
26 RSBJ: I fly a 707 (KC-135) and 737's and I have to say I have never once in thousands of hours used the eyebrow windows; even in tight visual patters or for
27 HAWK21M: You sure do.When you use the Newspaper to blank out the light. Amazing how these Windows are always Blanked out with Paper to stop the light. regds M
28 JBo: I'm not sure if Boeing would offer an eyebrow-removal program for the 717 as well. It appears the window design on the 717 (and DC-9, MD-80, et al) i
29 Gr8Circle: The old 707's used to have a sextant in the same position as shown in the pic of the VC-137C abvove...I have personally seen them being used during f
30 KELPkid: I'm familiar with the Mark III Sextant, and it's usage in flight would depend upon a clear shot of the horizon and the aircraft's eyebrow would have
31 ZANL188: Not particular what star you're shooting then are you?
32 N243NW: Thanks for the input. It makes perfect sense as far as costs are concerned. -N243NW
33 EssentialPowr: Out of an approx 6" x 10" window? Not a lot of field of view in the first place!
34 ZANL188: Hence my point that using the eyebrows for sextants is rather awkward and unlikely.....
35 2H4: That's what I was thinking.... So, forget about the reason for the installation of tiny eyebrow windows on the Boeings.....why the heck were tiny eye
36 ZANL188: Wasn't the JetStream originally a military design? In which case it would be easy to figure why they were removed for the commercial variants -- They
37 LongHauler: Canadi>n's arctic B737s were equipped with an Astro Compass, similar in use to a sextant. This was stored under the second jump seat behind the Captai
39 JetMech: The windows that I have seen blanked have always been on 747's. Most window cutouts in the pressurised skin will be re-inforced with a window forging
40 HAWK21M: Anyone aware of the entire Job of this Mod kit. regds MEL
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