Pentagon Research

DESCRIPTION: Taken right near the entrance between the two trees that burned. Since this was taken on the 13th and it wasn't in any of the outside photos from the previous two days, I'm assuming it was brought out from the inside.

KEY NOTES: Identifying compressor rotors is very difficult. Often the modern replacements have a very different appearance from the originals. Some had tie-rod holes added due to FAA safety changes over the years etc. The same rotor may have been used at different stages of the engines as well. The little slots can have any size fan blade put in them or not at all. I investigated the RB-211 which N644AA had on it and also the JT8D which was on the 737 and A-3 Skywarrior. I made no positive ID on either. I'm afraid that the only way that we'll know for certain is if somebody can find the same age engine that Flight 77 had on it (then you'd have to know the engine replacement history) and find an old one to dismantle.

Even though the engine has a large diameter opening there are stages of the RB-211 especially toward the middle/exhaust that are a much smaller in size. Even that piece that appears to be a cone of some sort to the left rear in the above photo could be an exhaust cone (see photo below). I've put a few photos of various rotors actually from the RB-211 here and the clearest illustration of one I could find.