View Full Version : what is this "+" mark on B737 cockpit panel?
yeoroom
2nd Feb 2010, 03:24
I've noticed that on the FWD overhead and main panel of B737-700, there are lots of " + " mark on the panel. (at least one on each plate)
example) under gear handle where flap limit speed is shown
FLAPS LIMIT (IAS)
1 - 250K
2 - 250K
+ (<-- this mark )
5 - 250K
what is this?
I couldn't figure it out nor find any information.
Please help my curiosity....thx
Nepotisim
2nd Feb 2010, 03:42
This has been answered a thousand times before.:hmm:
Here goes again. It is where the electrical connection is on the aft side of the panel. ie. It is where maintenance personnel push to make the connection when installing the panel.:ok:
yeoroom
2nd Feb 2010, 03:58
Sorry I didn't do the research... anyway thank you very much!!!
Pennellino
2nd Feb 2010, 07:55
Hi,when you don't have panel backlit you may also try to make a light pressure by your thumb on the "+", most of times It works fine fixing it in a while :)
PappyJ
2nd Feb 2010, 08:02
Not sure about the 737, but the Airbus (330, 340, 320) have similar markings (very small blue colored "+" marks).
These marks are used by maintenance and aircraft recovery personnel to check for damage, misalignment, etc, following a hard landing, severe turbulence encounter, off-airport landing, etc.
They take precise measurements between the various marks "+", and compare to acceptable values. From there, they can tell if the aircraft is bent or not.
Again, not sure about the 737, but......
Mungo Man
2nd Feb 2010, 08:35
It would have to be a REALLY hard landing to bend the overhead panel in the flightdeck!
PeePeerune
2nd Feb 2010, 08:44
Not sure about the 737, but the Airbus (330, 340, 320) have similar markings (very small blue colored "+" marks).
These marks are used by maintenance and aircraft recovery personnel to check for damage, misalignment, etc, following a hard landing, severe turbulence encounter, off-airport landing, etc.
They take precise measurements between the various marks "+", and compare to acceptable values. From there, they can tell if the aircraft is bent or not.
Again, not sure about the 737, but......
pappy j .. someone has made a right chump out of you.:}
mind you airbus are lightweight compared to the boeing's !!!!
PappyJ
2nd Feb 2010, 09:06
Mumbo and PP. Nobody has made a chump out of me. Check the AMM manuals for the aircraft.
I never in my wildest imagination ever though that I would have to explain this to a bunch of people who profess to fly airplanes as a profession, but...
Airplanes bend during flight!!! When they become "Stressed" they bend, but don't return to their original (designed) shape.
By measuring between key places in the aircraft, engineers can determine if it is bent or not.
Next,
mind you airbus are lightweight compared to the boeing's !!!! Apparently you haven't seen lightweight little A380 have you? Ever compared the operations cost of each? Seat by seat, Boeing looses!
Geeez, kids these days.
moonbug
2nd Feb 2010, 09:11
The "+" are alignment markers used by lasers during the etching/printing phase of the panel designs.
Normal stuff for CAD "Computer Assisted Drawings".
Mungo Man
2nd Feb 2010, 09:18
By measuring between key places in the aircraft, engineers can determine if it is bent or not.
Just winding you up! It makes sense really, I just think the 'key places' must be somewhere on the fuesalage rather than 18 inches apart laterally on the roof of the flight deck!
PappyJ
2nd Feb 2010, 09:25
Actually, there are thousands of these markings on a typical airbus, inside and outside.
kijangnim
2nd Feb 2010, 09:59
Greetings
These Marks are called mass point if you press it provides a ground contact enabling current to flow thus the back light to come ON in case of faulty switch, i.e all panel is lighted except one plate, then press the + of that plate.
but to me the most important is why the upper panel has two colors Dark grey and light grey, it highlights systems affected by the Fire Switch:ok:
hetfield
2nd Feb 2010, 10:09
They are just Attention Grabbers to distract pilots of speed, attitude and engine power e.g. THY at AMS.
There's a good picture of both sides of the panel in the thread listed below.
Scroll down to bottom.
http://www.pprune.org/tech-log/374967-small-crosses-drawn-all-over-cockpit-panels.html
PeePeerune
3rd Feb 2010, 08:27
Greetings
These Marks are called mass point if you press it provides a ground contact enabling current to flow thus the back light to come ON in case of faulty switch, i.e all panel is lighted except one plate, then press the + of that plate.
but to me the most important is why the upper panel has two colors Dark grey and light grey, it highlights systems affected by the Fire Switch
no no no..
pappy j:} says it for checking airframe rigging due to when it flys it bends and doesnt return back to its normal design.
that is quite funny, the thought of checking airframe rigging in the flight deck against the panels.:D
PappyJ
3rd Feb 2010, 08:45
Pee Pee. Are you really that daft?
Let me put it in simpler terms for you.
On the day that little yellow school bus that you were driven to that special school was build; when it was nice and new and exactly as designed, you could measure between various points throughout that bus (any point that was attached to the structure, super-structure or sub-structure), and record those measurements in a little note book (you probably colored in yours).
Then, after you drove that bus around - over a really bad road for instance - you could measure between those same points again. Then, you notice that several of the measurements differ from those recorded when it was new (in the regular school we called this geometry, trig, etc)
In aeronautical terms those changes in the measurements would lead us to believe that the structure had suffered some level of "Deformation" and those marks assist in measuring that deformation.
Next,
The "+" are alignment markers used by lasers during the etching/printing phase of the panel designs.
Why aren't they on all the panels?
forget
3rd Feb 2010, 08:56
Great thread :ok: Next ..... :p
PeePeerune
3rd Feb 2010, 10:04
Thanks for enlightening us all pappy j:}.
I suggest you also tell airbus aswell and get them to ammend the AMM ref
05-56-00 Inspection/Check of the levelling and measurement after abnormal operation of the aircraft.
Tell them to forget the datum points on the aircraft external structure and use the "pappy j:} + marks" in the flight deck.
Priceless :D
PeePeerune
3rd Feb 2010, 10:09
On the day that little yellow school bus that you were driven to that special school was build
pappy j :}. Did your school report end "Please try harder".
That really is priceless :ok:
The "+" are alignment markers used by l@sers during the etching/printing phase of the panel designs.
Normal stuff for CAD "Computer Assisted Drawings".
If so, wouldn't this process require more than one "+" per panel?
On all Boeing panels, the "+" does indeed align with the electrical contact. That is not to say that all panels have them.
Rgds.
NSEU
P.S. Tip: People casting aspersions on fellow PPRuNers' educations, should first check their spelling :ok:
PappyJ
3rd Feb 2010, 14:26
Build - built. Yep, you got me on that one!
forget
3rd Feb 2010, 14:33
P.S. Tip: People casting aspersions on fellow PPRuNers' educations, should first check their spelling
Pssst. Pappy. You missed the 'educations', bit like sheeps, the dodgy use of a colon and the missing full stop. ;)
muduckace
3rd Feb 2010, 15:36
Pappy J is wrong on topic but correct about fuscelage index marks. They are more commonly used in heavy maintenance when the aircraft needs to be jacked and shored prior to removal of too many skins. The aircraft is measured with survey equiptment then checked again after the structural work is complete. MDC products use a large button head rivit.