320tech From Turks and Caicos Islands, joined May 2004, 489 posts, RR: 5 Reply 4, posted (8 years 8 months 2 weeks 3 days 2 hours ago) and read 3975 times:
The device in the red circle is an angle of attack sensor.
Red, yellow, and green dots are blow out indicators for fire extinguishing systems and oxygen systems. Oxygen systems usually use green dots in my experience, though the placement of this one suggests that it could be the crew oxygen system.
The way they work is that there's a line from the bottle (O2 or fire ext) leading to the disk. If the bottle overheats or is fired, the disk gets blown out, giving an obvious indication that the bottle is empty.
Now, this could be something else on the MD-82 - I'm not familiar with it. But that's what it looks like to me.
The primary function of the design engineer is to make things difficult for the manufacturer and impossible for the AME.
Slam was looking for another MD-80 manual. The one nearest to hand did not depict the yellow spot.
Best I can recall DC-9/MD-80 had the oxygen blowout disk (green) on the lower right fuselage, just forward of the bag pit and very near the bottle.
A yellow blowout disk would be for overpressure discharge of the fire bottles but that should be somewhere within one airplanelength of the fire extinguishing system - in other words, near the engines and APU.
It also looks too big to be one of these plastic disks as I remember them being no bigger than a nickel. That object seems to be at least two fingers wide, measuring by the captain's hand.
Rain repellant blowout disk?
Waiting for an AA MadDog pilot or mechanic to jump in.
Happiness is not seeing another trite Ste. Maarten photo all week long.
Alias1024 From United States of America, joined Oct 2004, 2682 posts, RR: 2 Reply 8, posted (8 years 8 months 2 weeks 3 days ago) and read 3818 times:
As said by everyone else, the lever in the red circle is an AOA sensor.
The yellow dot is not a blow out disc. All AA MD-80s have them to help properly align the jetbridge with the aircraft. American paints a line on the floor of the jetbridge, and whoever is driving the jetbridge matches up the line with the yellow dot on the aircraft.
It is a mistake to think you can solve any major problems with just potatoes.
DeltaGuy From , joined Dec 1969, posts, RR: Reply 9, posted (8 years 8 months 2 weeks 2 days 23 hours ago) and read 3787 times:
Alias1024 got to it first...I was going to say, I had never seen these on the nose of a DL Mad Dog, but instead they carry an inverted T to help with jetbridge docking, located around the same place as AA's dot.
Skywatch From United States of America, joined Mar 2005, 923 posts, RR: 5 Reply 10, posted (8 years 8 months 2 weeks 2 days 17 hours ago) and read 3583 times:
I'm kind of new at this, but are those fins below the windscreen vortice creators to reduce cockpit wind noise? I just read around on here to learn, and have never worked on any aircraft at all. Feel free to correct me!
FBU 4EVER! From Norway, joined Jan 2001, 998 posts, RR: 7 Reply 14, posted (8 years 8 months 2 weeks 2 days 15 hours ago) and read 3532 times:
There are three pitot tubes forward of the windscreen,one for each pitot/static system (Captain's,First Officer's and the Auxiliary system).
Further down on the fuselage,there are strakes on either side of the fuselage.They serve to smoothen the airflow over the wing at high angles of attack and thus increase rudder effectiveness during flap extension/retraction.The old DC-9-41 has a hydraulically operated flap/rudder throw limiter that limits rudder deflection to 13 degrees under these circumstances.A complicated system that was replaced by strakes from the DC-9-50 onwards.
N685FE From United States of America, joined Dec 2003, 451 posts, RR: 12 Reply 15, posted (8 years 8 months 2 weeks 1 day 5 hours ago) and read 3320 times:
The 80's also have a rudder throw limiter, it also has a hyd assisted elevator when you push the stick past a certain number of degrees nose down. I forget the exact number, but it is to help during stalls, the 90's also have this system on the T/E of the engine pylons.
FBU 4EVER! From Norway, joined Jan 2001, 998 posts, RR: 7 Reply 17, posted (8 years 8 months 2 weeks 8 hours ago) and read 3107 times:
No,the strakes on the nose are for aerodynamic purposes as mentioned.They are also anti-iced by pneumatics on the MD-80 and electrically on the MD-90.The strakes on the nacelles are for stall-recovery purposes by adding more horizontal area in the tail area.The idea is that this will allow the nose to fall somewhat faster than the tail area due to drag,thus making deep stall recovery more likely.These strakes are not heated in any way.