As far as questions about the JS4100 go, I think this might be one of the more obscure:Why is it that you cannot push back with the engines running?Though I've flown in one, I don't remember the details at the start of the flight. It was at a remote stand at EWR, departing for IAD on ACA. At IAD, I definitely remember an awkward taxi-in to A7, re-inforced by seeing the JS41 lead-in lines while working the ramp with IDE (oddly enough, on the former A7, combined with A5 and renamed A3). If you want to have a look at them, go to IAD in Google Earth and step back to the image on 29.April.2002).I've done a quick Google search and a quick look around the manuals to check for reasons, but I can't find anything. Anyone with the info, please let me know - even if it's "RTFM" at least I'll know where to find it.Kyle

Regional turboprops are almost always parked in a position that allows taxi-in and taxi-out without needing pushback. The sim world misses this point, but if you google earth a few places (like KDEN) you'll see what I mean.

Thanks Dan.With UAX operations at IAD, props are pushed from the gates, though I know most other places use a simpler procedure. Then again, when you try to fit as many planes into one spot (IAD A gates), you don't have the real estate to allow pull throughs. Those gates were designed by a company I once interned for specifically for J41s and CRJs - not 170s, 700s, 200s and 340s (even though the same company did the re-design to the best they could).I'm 90% sure the departure at EWR (from the above-mentioned flight) was a taxi-out, as it was a remote stand. I also had the opportunity to fly on the 1900, but that was even further back. I definitely remember that we pulled through on the stopover in Bismarck, but the departure from DEN is eluding my memory (looking at the sat image of DEN, those are definitely EMB-120s and B1900Ds on the pull through spots). I don't remember the 1900 having a similar push restriction, however.To be placarded, there has to be some abnormally dangerous or potentially damaging risk and I'm curious of the rationale.Kyle

To be placarded, there has to be some abnormally dangerous or potentially damaging risk and I'm curious of the rationale.

It was (or is) a temporary restriction to prevent failure of the nose gear steering pinion on aircraft with a high number of landings.http://www.lmgtfy.com/?q=pushback+with+engines+running+prohibited+airworthiness+directive+plackard+jetstream

I would say I got totally owned by the LMGTFY, but ADs are not regulatory statements that lay out specific regulation. Rather, they merely state what changes are required in order for the aircraft to be operated legally (airworthy)."004-05-99: Temporary Placard to Prohibit Aircraft Pushback with Engines Running" simply means that the placard type and expected duration is temporary, but required in order to legally operate the aircraft. Why the limitation exists, however, would be found elsewhere, which is what I cannot find. In a similar manner, spins are prohibited in C152s that aren't Aerobats, and that limitation is found in the POH. The associated placard on the panel is mandated by AD, but the AD itself isn't the reason for the placard.Thanks for helping in the search though.Kyle

Why the limitation exists, however, would be found elsewhere, which is what I cannot find.

The search was just a quick way of providing a list of documents that contain the explanation - no "owning" was intended.The gist is that, if the steering pinion has a specific part number and the nose landing gear has accumulated more than 12,000 landings since new/overhaul, the placard must be installed until the NLG can be inspected and possibly replaced.The problem that is being prevented is being described as: "To prevent failure of the steering pinion in the nose landing gear (NLG), which could result in a loss of steering and possible damage to the airplane during takeoff and landing"Presumably a pushback with engines providing idle thrust places a larger strain on the nose landing gear than if the engines are shut down.

The search was just a quick way of providing a list of documents that contain the explanation - no "owning" was intended.

Even if it was, I'd assumed it was in good fun. You've definitely helped me out before so I'd assumed you were trying to be helpful again - I guess I was just feeling particularly caustic last night...det må I unnskylde.Thanks for the expanded explanation. That definitely answers the question. I'd assumed it was an issue with the engines, or a safety of push operator issue (though looking at pictures, you're closer to the props pushing a SAAB than you are a JS).Thanks,Kyle