Chicoartist wrote:
Wake turbulence -do- have an effect on keeping the old girl straight!
You should see the video I have of a MITO at Barksdale back in the day with G-model BUFs and A-model 135s. Black smoke all over the sky, and one BUF nearly loses it, or appears to, after obviously hitting some bad air. He's slipping and skidding fairly radically for such a large a/c, and very low to the ground. He recovered minus a seat cushion or two, I'm sure. Awesome!
Wade
Wake turbulence does have an effect, but I don't believe that's what caused the directional control problems in this case for a few reasons:
1) The drifting aircraft was # 2 in the takeoff sequence. Wake turbulence is only generated when an aircraft rotates and the nosewheel is off the runway. If you note where the #1 aircraft rotates, you will notice that the # 2 aircraft has directional control problems well prior to the rotation point of #1.
2) None of the other aircraft have any directional control problems on the takeoff roll to the severity that # 2 had.
3) The #2 aircraft has directional control problems both on the takeoff roll as well as the high speed back taxi. If it were wake turbulence, it would undoubtedly affect the other aircraft taking off as well. It didn't.
4) Generally speaking, wake turbulence has the most effect when it involves a case of a lighter aircraft taking off behind a heavier one. Although not impossible, it is unlikely that the wake turbulence from one B-25 would be strong enough to upset another one to the extent we see in this video.
This would indicate to me that one of two possibilities occurred: either the pilot is not using enough rudder to keep the aircraft straight or he had some kind of asymmetrical power and/or drag issue. This could have been caused by either a lack of power on one engine, a dragging brake, etc. If this was the issue, I don't see why he would be in such a hurry to take a bad aircraft into the air without investigation.
Also, a small observation. Notice that as #1 is starting to rotate, the #2 B-25 makes a pretty hard turn to his left just as he starts the takeoff roll. He then corrects and lines up but has drifted considerably off the runway centerline. This small jink as he's applying takeoff power is odd, as every airplane is on the runway and lined up pointing straight down the runway. Something caused that small jink, but I don't know what. Perhaps his nose wheel was not centered when he applied takeoff power?
So, either the pilot has seriously misused the rudders to keep directional control OR he had some kind of directional control malfunction which dictated an abort and he didn't investigate it very thoroughly. Added to this fact, he did a high speed back taxi on an active runway, without communicating it to the other flight members. Any way you slice it, this all points to very bad pilot judgement. I wonder just how much experience this pilot actually had who was flying the # 2 B-25?
Anybody see anything else that I could be missing?
Question for you B-25 pilot types. Is the B-25 nose wheel steerable, or is it just free-castoring? Could a defective nose-wheel have caused this directional control issue?