Yesterday, while waiting a seeming eternity in a DC-9 at the hold short line at Chicago’s O’hare airport, I noticed a strange attachment on the nose gear of the Boeing 717 next to us. It almost looked as if someone had forgotten to disengage part of the tractor from the plane after it was pushed back from the gate. Looking at some pictures online today, I saw the same gizmo, so obviously it was normal. It appears to be a black, square bracket that attaches to the outside center of each nose wheel, and then sits behind the nose gear, almost touching the ground.
Having never seen this on any other airplane, I’m pretty curious to know what it is/does. Anybody?
It’s a nosewheel Spray/Foreign Object Deflector. Keeps the nosewheel from kicking water/junk back into the aircraft.
They are found on MD-80s, MD- 90s, and 717s. They are also sometimes added to other models.
Its like a mud guard for an aircraft.
The 727s and MD-80s have them also. If the wheels kick up water/snow/sand/salt etc, it will go airborne down the length of the fuselage, and the fuselage mounted engines (on the outsides of the tail) will suck the stuff up. That mudguard tosses the filth back onto the ground so the engines don’t eat the dirt and become damaged.
For the curious, there is a decent pic here.
Yep, similiar purpose as a truck mudflap, only a lot more expensive and missing the chrome naked wimmin silhouettes.
I don’t think they came as standard equipment on the 727, or at least ours doesn’t have one. It does have nosewheel chines, though.
Thanks all for the replies. I never thought of that. Makes sense, though.
You own a 727?
Belongs to my employer. I wish it were mine, I would have the coolest campsite at Oshkosh every year. I do have a key to it, though, which I’m happy to show off given the least little excuse. 
A mud guard for planes! Reminds me of the General’s B-25 with chrome hub caps and white-sidewall tires in the movie Catch 22.
Is it the ignition or the door key? Can we see it?
I don’t know if they’re standard, either. We don’t get very many 727s in (we’re good for 737, 757, MD-80s, and A-319/20/21s), but FedEx does send one in every morning at 7ish and back out around 10pm-ish. All of those 727s have the mudguards on both the nose gear and the main gear. Of course, it could just be a FedEx quirk, not a general 727 thing.
**It’s a door key. There is a hydraulic valve at the rear of the jet that we use to lower the airstairs. We installed a lock on the valve’s access panel to keep people out of the plane. Otherwise, anyone could just walk up to the jet, open the panel, and release the pressure keeping the stairs up.
It’s not very impressive looking, I’m afraid. It doesn’t even say “Boeing” on it.
I personally wanted to install a car alarm. I thought it would be cool to hop out of the plane, hit the remote button, and have the landing lights flash and the gear horn sound twice. They wouldn’t let me, something about the FAA or something.
Oh well.
Leave it to a Tennessee company to have mudflaps on their airplanes. 
After taking a look at the FedEx 727 at work yesterday, I’m sad to report that it didn’t have the mudflaps, so apparently they don’t all have them.
There was, however, a Delta MD-88 with a beautiful set, front and rear, and here they are:
http://members.aol.com/KCB615/nose.jpg
http://members.aol.com/KCB615/main.jpg
KCB615 if you look at those FedEx 727s I bet they’ll have chined nosewheel tires.
Chined tires are what the rest of the world uses to deflect water and debris away from aft-mounted engines. McDonnel Douglas uses spray deflectors.
I’m away from my home computer now, and can’t access any of the photos I have of 727 tires to demonstrate what a chined tire is. It’s basically a ridge of rubber that extends out from the wall of the tire, perpendicular to the axis of rotation.