Rolling t/o?

[Guest tomahawk_pa38]

I notice that the recent reissue by the CAA of Manual of Air Traffic Services states the following in the section about take - off clearances:-12.8 Expedition12.8.1 When given the instruction 'cleared for immediate take-off ' it is expected that the pilot will act as follows:a) At the holding point, taxi immediately on to the runway and commence take-off without stopping the aircraft. (Not to be given to Heavy aircraft);Note the last phrase in brackets - still not sure why though.

[Guest Lenny Zaman]

commonly practised among the world for economic reason. From a safety point of view it is not the best thing to do, but it's not dangerous at all either.Last time i was flying in Seville, a Vueling A320 was cleared for takeoff while he was still 200m away from the holding point. I saw lights coming on, the plane taxying at +-20kts on a 180(wide) taxiway and takeoff power was set the moment they were 45

[Guest ProjectXWinds]

I can't imagine the amount of fuel a rolling takeoff would save would be consequential. However, do note that full power was not applied until the aircraft was aligned with the centerline.I would guess the purpose of stopping is to be certain that you are lined up correctly with the centerline, before applying TO/GA thrust. Applying that kind of thrust in a non-T/O environment would be damaging to the wheels, etc., and wouldn't be safe.Although, if you're lined up on the runway, It wouldn't matter if there was an aircraft on approach or not, anyway. You've got the active. That's what hold short bars or for.My $0.02

[victorlima01 2]

Biggest aircraft I ever saw conduct a rolling takeoff was a 777-200 in Schiphol. I had the priviledge of being in the jumpseat at the time and as we were approaching the hold bar for the rwy and conducting the before takeoff checklist, the controller told us to be ready for a quick takeoff and seconds later asked us to align and go immediately. It was quite an experience to watch a huge 777 from the flight deck perform a quick 90 degree turn and go to "thrust set" in a matter of seconds. The guys flying had to have very cool hands and nerves of steel to do everything there needed to be done in such compressed time and without missing a beat.Thus it is my opinion that rolling takeoffs are okay to be exceuted, as long as there are two very well trained pilots handling the aircraft and that these men's minds are 5 minutes ahead of them.Best Regards,Victor LimaSBGLhttp://www.precisionmanuals.com/images/forum/800driver.jpg

[Guest AJ]

>Almost every time I've ben on small aircraft pilots have done>a rolling takeoff, it's perfectly normal procedure, and is>used a lot by low-cost airlines because it saves time and>fuel. If you think about it, there's absolutley nothing>unsafe about it as long as all the procedures have been>completed correctly.>>Granted, I've not seen it done as much in larger aircraft, but>I can't think of any reason that larger aircraft such as the>747 shouldn't be allowed to do rolling takeoffs - it's still>an aircraft, after all :(There is good logic behind this recomendation for an aircraft of the size class of the 744, especially if it is heavily loaded. On the ground it is not nearly as maneuverable as a 737 or A320. Moreover, if the pilot happens to miss the center line a little when turning onto the runway, and then overcorrects a little in the opposite direction, he could end up weaving down the runway even as the engiens are spooling up to takeoff power. This would increase takeoff distance, be uncomfortable and alarming to passengers, and also be potentially dangerous.Andrew

[Guest hirnwut]

>Thus it is my opinion that rolling takeoffs are okay to be>exceuted, as long as there are two very well trained pilots>handling the aircraft and that these men's minds are 5 minutes>ahead of them.>>Best Regards,>Victor Limawell. I hope every pilot I am flying with is well trained ;-)

[Guest BlueRidgeDx]

I haven't seen anyone mention it yet, so I figured I'd throw it out there for anyone interested...There is a performance penalty associated with performing a rolling takeoff. Takeoff thrust isn't "set" until further down the runway, and that has to be taken into account on short or contaminated runways, or any time takeoff weight is limited by obstacle clearance.Depending on conditions, doing a rolling takeoff with FLEX thrust can severely limit MTOW. There's nothing unsafe about it though, because the performance calculations would have been predicated on its use.In fact, the tools we use to calculate the takeoff performance defaults to a rolling takeoff. I have to deliberately tell the computer that I want data for a static takeoff if conditions warrant one.Regards,Nick

[cowpatz 243]

The video seemed to pretty much show a normal TO although the crew did seem slow to apply TO thrust. Actually apart from the slow application of power this is a text book Boeing recommended TO. As long as thrust is advanced after the aircraft has completed the turn there is no problem. The issue is controllabilty. If an outboard eng fails at TO thrust it is very difficult to keep the old girl straight. If you do not retard the thrust levers asap you will be spun around and off the side for sure. It is one of the reasons why we "stand the levers" (set approx 70% N1 or about 1.1 EPR on RR) and let things stabilise before selecting TO/GA. If an engine hangs and the other 3 go forward then you are in trouble. I am at a loss to explain why PMDG recommend a full stop.There are 2 methods of performing a rolling TO:1. When cleared for TO maintain taxy speed onto the runway. When alligned with the runway centreline apply thrust to 70%N1 or 1.1 EPR approx. Allow engines to stabilise momentarily (less than 2 sec)and then set TO thrust (TO/GA switch). There is no need to stop the aircraft prior to applying thrust.2. If holding in position on the runway then release the brakes and apply TO thrust as described above.The aircraft should only be held on the brakes for a static run up (icing conditions etc). Holding the aircraft on the brakes while applying power increases the risk of FOD and abrasive particle damage.There is a negilable difference in TO performance between a standing start and a rolling TO.Perhaps PMDG need to ammend their manuals to bring them into line with standard Boeing procedures.....another wiki missive??????CheersSteve

[CF104 0]

According the the 744 FCTM (Flight Crew Training Manual), a Rolling Takeoff is the recommended procedure. I'm at work and don't have access to my manual from here but will cut and paste the appropriate info in the morning when I get home.Cheers,JohnBoeing 727/737 & Lockheed C-130/L-100 Mechanichttp://www.sstsim.com/images/team/JR.jpg

[cowpatz 243]

I wouldn't worry John,What I posted above is from the 747 Flight crew training manual.By the way John I see you work on Boeings. Can you tell me, by any chance, what the service bulletin/AD number was for the modification to the 747 fuel system following the recommendations of the TWA800 accident? CheersSteve

[Guest abulaafia]

I fly Cathay Pacific 747's about 130'000 miles a year, and rolling takeoffs are absolutely normal - most often ex TPE with the evening flights.

[CF104 0]

Hi Steve,There were several AD's issued due to the TWA800 accident.The AD's can be found at www.faa.govThe main AD is:AD 99-08-02 R1Other relevant AD's to the Centre tank are:AD 2002-24-51AD 2002-19-52AD 2001-21-07AD 2001-12-21Cheers,JohnBoeing 727/737 & Lockheed C-130/L-100 Mechanichttp://www.sstsim.com/images/team/JR.jpg

[Guest BlueRidgeDx]

>There is a negilable difference in TO performance between a>standing start and a rolling TO.>>Cheers>SteveHi Steve,I should have qualified my performance remark a bit better. I cannot speak specifically about the 747...I've never dispatched one. In general terms however, I would maintain that - depending on the airframe in question - there can be a significant penalty for a rolling takeoff.Maybe it would be more accurate to say that we can get a performance CREDIT, for performing a static takeoff.In the CRJ, on a short field like KEYW (Key West) on a hot day, I could squeeze on perhaps 1000lbs additional payload by specifying a static takeoff.Now, I know that 1000lbs is a drop in the bucket for a 747, but for a CRJ thats an 8% increase in allowable payload. Not too shabby.Regards,Nick

[CF104 0]

Nick,>There is a negilable difference in TO performance between a>standing start and a rolling TO.That is a direct quote from Boeing in their 744 FCTM and rolling takeoffs are the preferred method.Cheers,JohnBoeing 727/737 & Lockheed C-130/L-100 Mechanichttp://www.sstsim.com/images/team/JR.jpg

[Guest BlueRidgeDx]

Maybe we're misunderstanding each other?1) As I stated in my previous post, rolling takeoffs are the default (read: preferred) method for the CRJ too. I'm not debating that.2) I qualified my remarks (or tried to, anyway) by stating that I was referring to the CRJ in my first post. I realize that this is a discussion specifically about the 747, but since no-one had touched on the "performance" aspect of a rolling takeoff, I thought I'd bring it up. Prior to my reply, the majority of the posts seemed to center around "safety", or lack thereof.I can't speak specifically about the 747's takeoff performance, as I have no real-world experience on the type. I can, however, speak in general terms...and thats what I was trying to communicate.Put another way, setting FLEX thrust (AT or De-Rate methods) is also the preferred method for takeoff in just about every jet-aircraft. But doing so can also incur a performance penalty. Similarly, rolling takeoffs may be preferred, but depending on a whole bunch of variables, doing so could result in bumped pax, payload or fuel. The only point I'm trying to make here is that the "preferred method" is not necessarily synonymous with "max performance". If you're saying that when MTOW is limited by something other than a structural limitation, performing a static takeoff only yields a negligible performance gain on the 747-400, then I believe it. But for the sake of discussion, I just wanted to point out that on other airframes, such as the CRJ-200, the performance difference can be fairly substantial.Take care,Nick