Quoting Flaps (Reply 96):

Thanks for your post. On the spot, the info and the insights ...

Best Regards

TRB

well, the B737-800 is known to be in some cases a challenging aircraft considering tipping. but its not all the B737-800 fault, it is a combination of factors. usually for ramp ops, you try to counter tipping with your bag, cargo and mail loading procedure. first of all, no modern aircraft will tip, if after the main landing gear every row is filled with men wearing winter cloths. but if you have something loaded in the rear, it will certainly tip.

the 738 can be extremely critical with one operator, and no problem with the other. when working on them, you will find them loaded with 2.5 to aft, fwd empty, as well as aft empty and 3 to fwd (all bag/gargo/mail).

just imagine a 738 with, let's say 6 rows of business, and those aren't booked. eco is nearly full... you not only have a tipping, but also a trim issue. so you counter by filling up the forward hold with the densest cargo you have and leave the lighter rest for the rear if there is a possibility.

and the pantry needs to be considered as well: if an airline is catered return and calculates 0.3 liters of drinks per passenger, this means you may have at least a 120kg at the foremost or aftmost position, changing also a lot.

and then there is the issue with disembarking: if docked to a jetty, the forward rows will empty with the aft ones still occupied. the 738 nose gear suspension will vary for at least 20cm during a jetty disembarkation, while on open positions with forward and aft door in use, there is no problem at all!

the general dilemma with tipping is, that airlines wish a trim at aft limits, since this is considered fuel efficient. the 738 gets there in most versions only by loading it in the rear... which sucks considering tipping.

the A320series behaves the same, and a A321 with 4 to aft and fwd door use is VERY critical, especially with charter operators and their huge aft galley catering weight!

so one might think that the DC9 or Fokkers or TU-154 must be better since they can be leaded forward... well, also wrong. since due to the engines the cg will be roughly about 2/3 of the fuselage, meaning that a fully loaded MD80 is VERY noseheavy (and won't tip) while an empty MD80 can't fly. so to counter the noseheavy tendency, all the DC9 are loaded aft fully and then fwd... resulting in the tipping dilemma.

the TU-154 is different. the plane is an animal defeating all laws of ramp ops. three very heavy engines in the back, middle door and business always disembarking first. though the TU5 has a small tail stand, it is never used during ops. russian aircraft in general are different to western ones and not comparable at all.... also snow and ice on the wings seems to have no effect, overloads don't matter... but that's a different story.

then there is the ATR-72, a "plane" with a tail stand that is worth wile having. i have seen AT7 with their nose wheel in the air and sitting on the stand during loading and boarding (the problem is boarding with the AT7 due to the rear door, not deboarding). if you have the crew of an AT7 gathering in the rear and maybe one or two other staff, the plane sits on its stand (also depending on config and pantry), while the weight of the two pilots in the cockpit will most likely be enough to counter boarding passengers. but the AT7 is a different story all together....

there are several planes making use of a tail stand in one or the other way: 722, 747 cargo, 146 cargo, AT7 (no stand for the AT4) TU5, IL6, SF3, S20,...


to prevent tipping, airlines issue a max for the aft hold, which is roughly 1900/2500/3500 for the 319/320/321 in all eco... the 73G/8/9 will be about 1300/2500/3500, also depending on config, business and pantry.

P.S.: i loooove the TU5...

Quoting DDR (Reply 82): The ATR-72 uses a tail stand also. It's stored beside the rear door and the flight attendant hands it to the ramper.

Photo of ATR-72 tail stand.

Quoting TVNWZ (Reply 99): Quoting N1120A (Reply 89): The extra width on the A32S is not enough for anyone to actually notice it. I notice the wider aisles. Two inches extra on each side can feel dramatic. If you fly as much as I do, you notice. It originally was one of the big selling points for AB believe.

Agree. The approximate 6 inch wider A320 cabin is quite noticeable, especially if you immediately connect from one to the other. As you say, the aisle width is very noticeable, also the additional inch of seat width on some A320 family operators. Even in a room in your house as narrow as a 737 cabin, if you moved one wall 6 inches further out, you'd notice it.

However, I doubt many passengers choose a flight based on whether it's a 737 or A320. I don't on flights under about 2 hours but on longer flights I prefer the A320 when there's an option.

Ah, the irony. I just flew on a 739 that was nose heavy - one row of passengers in the forward economy cabin had to be moved to the back of the plane.

Quoting Adipasquale (Reply 91): Don't say such things! Many people on a.net are convinced the A320 family is so much better and more comfortable than the 737 because of the slight extra width which they can absolutely feel, just like the princess and the pea!

Believe me... I love to feel that "extra width"!

 

Quoting TVNWZ (Reply 88): extra width in the tube...

Need I say more?

Quoting questions (Reply 105):

Nope. Covers it.

Quoting antoniemey (Reply 95): E-145s have had that, too. Basically EVERY aircraft has its idiosyncrasies. Every aircraft has it's perfect balance point, and every aircraft has a loading point at which it will tip. Some aircraft have enough of their mass in the right places that they're really hard to tip. Some, due to shrinks, stretches, or just design factors for optimal flight, are much easier to tip.

That is to get the CG in acceptable range for Takeoff on a small aircraft that is empty.

That is a huge difference then an aircraft operating under normal everyday circumstances that likes to sit on its tail.

There was never a threat of a 145 sitting on its tail.

Quoting N1120A (Reply 89): The extra width on the A32S is not enough for anyone to actually notice it.

This is entirely incorrect. The average width of an A320 series seat is about an inch (give or take) more than an average 737 seat, and it is DEFINITELY noticeable. One has more room at the hips, and more at shoulder height as well; the latter is most noticeable to me.

30 series Learjets also use tail stands when loading both bags and fuel. Of course, the 35's are unbalanced side to side as well, so have to be careful when loading fuel not to have too much of a differential. fun to have a plane that is prone to tipping over in pretty much any direction...

Quoting jfklganyc (Reply 60): Been flying for 12 years with the airlines...never saw a tail stand in use at any airline with any aircraft. Not a normal thing. And yes, a garbage design. A dog of an aircraft stretched too far imo. Not an issue with the 321 or any of the E jets to counter a claim above. Only on a.net could using a tail stand during normal airline ops be justified as normal hahaha

Come to the cargo world, you'll be surprised. I see it everyday. FedEx even tethers the nose gear on their MD-11s when loading/unloading.
Pat

Quoting jfklganyc (Reply 107): That is to get the CG in acceptable range for Takeoff on a small aircraft that is empty.

Pretty sure everyone here is perfectly aware of what moving passengers prior to takeoff is for, but it's not just on empty small aircraft.

Quoting jfklganyc (Reply 107): There was never a threat of a 145 sitting on its tail.

I'm pretty sure I could tip one if I wanted to. The 900 doesn't "want" to sit on its tail any more than the 145 does. If it DID "want" to sit on its tail, it would be a monthly occurrence around the world. And yet, we've heard of, what, 1 or 2 incidents since the type entered service where it started to tip?

You may not like the 900, that's fine. You may think that it's too far of a stretch on an airframe optimized for a smaller size, and you'd have a valid argument. But claiming that it's badly designed because it often gets most of its cargo loaded up front instead of in the back is just ridiculous.

I don't care how United's management spins their PR on the 737-900. It will never be a 757-200 replacement. I would rather work a bulked out 757 over the 900 any day. The headroom alone in the pit makes a huge difference.

Quoting ramprat74 (Reply 112): The headroom alone in the pit makes a huge difference.

No one will ever dispute that.

Quoting Ty134A (Reply 101): well, the B737-800 is known to be in some cases a challenging aircraft considering tipping

All our B737-800s are tail heavy due to the "sliding carpet" installed in the aft cargo. A great tool for quicker loading/unloading of the aft cargo, but we must be aware of tail tipping on every boarding and deboarding - always a topic in our briefing.

Poor B737-900ER - they are always bashed for something. But they are still very qute planes, wish we had them in our fleet  

Quoting jetblueguy22 (Reply 110): Come to the cargo world, you'll be surprised. I see it everyday. FedEx even tethers the nose gear on their MD-11s when loading/unloading. Pat

Cargo guys can also fly in pjs after takeoff. 2 different worlds. Tail stands are not normally used in pax operations

Quoting antoniemey (Reply 111): I'm pretty sure I could tip one if I wanted to. The 900 doesn't "want" to sit on its tail any more than the 145 does. If it DID "want" to sit on its tail, it would be a monthly occurrence around the world. And yet, we've heard of, what, 1 or 2 incidents since the type entered service where it started to tip? You may not like the 900, that's fine. You may think that it's too far of a stretch on an airframe optimized for a smaller size, and you'd have a valid argument. But claiming that it's badly designed because it often gets most of its cargo loaded up front instead of in the back is just ridiculous.

It is not the same. I flew the 145 for years and we never gave a thought to tipping the airplane. The 739 is getting a tailstand to prevent it from happening and staggering deplaning. That is a garbage design and not normal for a pax aircraft operating under everyday circumstances.

Quoting jfklganyc (Reply 115):

Again, not all the time. It's a preventative measure for the few times to been a possible occurrence. I flew it for many years and never had an issue. I'm not going to say it's the best design in the world but it's no where near as bad as you want to make it out to be. When you've logged more than 0 hours in it I'll listen to your opinion.

I wonder if the heavier engines and redesigned tail cone of the 9MAX will help alleviate some of this... Or will the 8" raise to the front landing gear encourage it to tip more frequently?

Has the fore/aft weight distribution changed much with the 9MAX in relation to the 9ER?

Quoting ramprat74 (Reply 112): I don't care how United's management spins their PR on the 737-900. It will never be a 757-200 replacement. I would rather work a bulked out 757 over the 900 any day. The headroom alone in the pit makes a huge difference.

The 900 is in fact not a 757. It can't replace that beautiful bird! I prefer working the 757 any day of the week. The only thing is that at least the sUA birds have the nesting system, and the sCO birds do not. (except the 753 which has the carpet)
No problems going Westbound in the winter and no weight restrictions.

I don't think that anyone at UA enjoys working the 800 though. No carpets or nesting systems - just good old fashioned manpower!!

[Edited 2016-02-07 10:24:51]

Quoting boilerla (Reply 1): Delta literally uses a stick to prop up the tail of the plane.

I sat next to a DL ramper last night ATl-FLL on a 737-900, and he confirmed this. Aircraft arrives, is blocked, gets it's stick in the umm...tail, every time.

The F/A's I spoke with yesterday acknowledge the -900's efficiency vs the 757 but say that the -900 is very hard to work from the inside. They have been deployed on west coast-ATL meal services and the limited galley space - even up front - makes it hard to provide a gracious service. The dinner rolls are supposed to be served warm, but there is not enough oven capacity to heat them and the main entree simultaneously.

Who operates this version?.

Quoting CRJ900 (Reply 114): All our B737-800s are tail heavy due to the "sliding carpet" installed in the aft cargo. A great tool for quicker loading/unloading of the aft cargo

yep, i know! i have had my "fun" with these B737s (and since keeping a close look at the nosegear).... but the carpet is not that much of a help if you have a good team of loaders. the'll load faster than the carped slides.....

My understanding is that UA expects using tail-stands on its 737-900s to allow simultaneous loading / unloading of the fore and aft pits, instead of the current S.O.P. of loading the front compartment first (departure), and unloading the rear compartment first (arrival).

Supposedly to be rolled out this Spring. Should allow for quicker turns.

Quoting Schweigend (Reply 122): Supposedly to be rolled out this Spring. Should allow for quicker turns.

I wonder how many years down the line it will be before they supply the tail stands to stations like BNA that see the 900 as a periodic up-gauge, rather than a regularly scheduled visitor.

Quoting avek00 (Reply 52): Airlines engaged in international air transport are forbidden by international law and national regulations from self-insuring on accident liability. The third-party insurance requires enables market forces to often promote, rather than undermine, the interests of aviation safety.

You are definitely correct in respect to passenger and third party. Airlines could self-insure hull and engines. However, financiers and leasors have their requirements. Even when selling or leasing say ten new aircraft, financier / leasor may still take floating or fixed charges over otherwise unencumbered older aircraft to cover any shortfall. Air frame and engine manufacturers cannot self-insure for product liability. Sorry off thread.

Quoting Schweigend (Reply 122): My understanding is that UA expects using tail-stands on its 737-900s to allow simultaneous loading / unloading of the fore and aft pits, instead of the current S.O.P. of loading the front compartment first (departure), and unloading the rear compartment first (arrival). Supposedly to be rolled out this Spring. Should allow for quicker turns.

  

United has designed and developed it's own tail stands for a fraction of the price of the OEM, that will be appearing for the -900ERs soon.

Quoting bennett123 (Reply 120): Who operates this version?.

In the USA...United, Alaska, Delta.

Quoting Schweigend (Reply 122): My understanding is that UA expects using tail-stands on its 737-900s to allow simultaneous loading / unloading of the fore and aft pits, instead of the current S.O.P. of loading the front compartment first (departure), and unloading the rear compartment first (arrival). Supposedly to be rolled out this Spring. Should allow for quicker turns.

Well that makes SOOO much more sense. Continental/United have been flying the 739s for over a decade, so I couldn't figure out why this is only happening now. The 739 has always had weight issues, but the risk of tipping can be minimised if probably managed. Moving to simultaneous loading explains why they suddenly wanted to invest in tail stands, as managing loading/unloading worked pretty well for 10+ years.

Quoting infiniti329 (Reply 5): As far as 737s go, it is possible with 738s and larger.

As I recall from my load planning days, the 737-200 and -300 were both tail heavy.

Quoting questions (Reply 9): What a poorly designed variant.

See above ^^^^^^^^

Quoting xdlx (Reply 13): When the MFG gives you a stand so the airplane does not tip over.

I can recall loading and unloading an L-188 (cargo) with only one cargo door, without using a tailstand........you had to push a pallet on, then push it back, partway (carefully) then roll on the next pallet, leave it in the doorway and push the other pallet all the way back and repeat this step until you've got it loaded.


As mentioned before, the 727 had this same problem. When I worked at DL ops at SLC, pre WA merger, we had one 727 that was RON. Instead of putting on ballast fuel, we dropped the rear airstairs and locked it from the inside with a piece of plywood, cut to shape, to fit next to the door handle. After accidentally leaving it on board several times after the a/c left, we put a comat label on it with a return address AND a "remove before flight" flag bolted to it. AA, on the other hand, left their airstars up and boarded ballast fuel. One overnight, they forgot to have fuel put on and when the wind came up the next morning, swung the a/c into the jetway.


When I was in the Air Force on Shemya, we had a C-124, once a week. It was a good idea to use the tailstand on Ol' Shakey when you were loading and unloading or you might have a problem.

Quoting antoniemey (Reply 123): I wonder how many years down the line it will be before they supply the tail stands to stations like BNA that see the 900 as a periodic up-gauge, rather than a regularly scheduled visitor.

I don't know, but I wonder if a tail stand could be carried inside each 739, stowed perhaps somewhere in the aft compartment, so that stations would not have to be provisioned with them ??

If such a thing were possible, the stand would have to be kept in pits 5-6 (the area from the rear door to aft bulkhead), since pit 4 has the Telair "Magic Carpet".

Quoting CALTECH (Reply 125): United has designed and developed it's own tail stands for a fraction of the price of the OEM, that will be appearing for the -900ERs soon.

That is great to hear. I've seen photos of them (they're orange and appear to be about 2" in diameter), with the attach point just to the right of the tail skid assy. In fact, tonight I saw one plane -- an a/c in the 880-890 range -- with the attach point already present, it was an orange circle.

Do you know whether or not the stands will be stored within the planes themselves?

Quoting RyanairGuru (Reply 127): Well that makes SOOO much more sense. Continental/United have been flying the 739s for over a decade, so I couldn't figure out why this is only happening now. The 739 has always had weight issues, but the risk of tipping can be minimised if probably managed. Moving to simultaneous loading explains why they suddenly wanted to invest in tail stands, as managing loading/unloading worked pretty well for 10+ years.

IIRC, the differential loading scheme really started being implemented around mid-July 2010, after CO's retro-jet N75436 experienced a minor tail-tip (just a few feet) upon arrival from SEA while parked at IAH gate C-21. Before then, the simultaneous process had been the norm. I actually witnessed the event -- and there was a thread about it, to which I contributed (some of my earliest posts on this forum)   ....

Continental Retrojet Goes Tipsy


View Large View Medium

Photo © Andrew Compolo



P.S. -- the above-linked thread from 12 Jul 10 also contains many photos of notorious tail-tips involving all kinds of aircraft types! See post 36 by Viscount724

[Edited 2016-02-08 23:21:40]

Quoting Schweigend (Reply 129): Quoting antoniemey (Reply 123): I wonder how many years down the line it will be before they supply the tail stands to stations like BNA that see the 900 as a periodic up-gauge, rather than a regularly scheduled visitor. I don't know, but I wonder if a tail stand could be carried inside each 739, stowed perhaps somewhere in the aft compartment, so that stations would not have to be provisioned with them ?? If such a thing were possible, the stand would have to be kept in pits 5-6 (the area from the rear door to aft bulkhead), since pit 4 has the Telair "Magic Carpet". Quoting CALTECH (Reply 125): United has designed and developed it's own tail stands for a fraction of the price of the OEM, that will be appearing for the -900ERs soon. That is great to hear. I've seen photos of them (they're orange and appear to be about 2" in diameter), with the attach point just to the right of the tail skid assy. In fact, tonight I saw one plane -- an a/c in the 880-890 range -- with the attach point already present, it was an orange circle. Do you know whether or not the stands will be stored within the planes themselves?

The new tail stands will be implemented in the hubs by next week. Then the major line stations afterwards. We have been testing two types of tailstands: One built by Boeing; and the other designed in-house. The in-house designed tailstand was the better choice and they are manufacturing them quickly. Hopefully this will be completed by the end of the month. As far as I know, they will be stored at the station/hub instead of on the aircraft.) CALTECH is correct that they are bright orange poles, and there is an attach point where to insert it.

Quoting Schweigend (Reply 129): If such a thing were possible, the stand would have to be kept in pits 5-6 (the area from the rear door to aft bulkhead), since pit 4 has the Telair "Magic Carpet"

I thought about that, but you would need something like a slot to hold the pole like you have to close the doors on the E170-175. But these would take up room and you would need them ASAP to start the unloading process. So the best option is to keep them at the gate. Probably in a jetway holder or something of that type container.

Quoting caoimhin (Reply 29): I'm sure engine 2 happily contributes to this condition. Still, I find it hard to believe that this occurs absent a breach of loading/unloading procedures. If this were a reasonably foreseeable condition of the aircraft during a by-the-book disembarkation event, that tail support would certainly be a design feature. Even without complete compliance with protocol, if it happens often enough, that tail support should still certainly be a design feature.

I doubt that it happens all that often with the 727, because the airstairs are more than likely, always down and locked when on the ground. However, as I mentioned in Reply #128, they ARE inherently tail heavy and with the right circumstances, will, tip. Since the 737-300 was so tail heavy, I AM surprised that Boeing didn't take that into account when doing any of the subsequent "stretches" to the airframe. You could load all 4 bins to the max on the -300, with a full load of pax and it still would be at the aft limits.

Quoting Schweigend (Reply 129): That is great to hear. I've seen photos of them (they're orange and appear to be about 2" in diameter), with the attach point just to the right of the tail skid assy. In fact, tonight I saw one plane -- an a/c in the 880-890 range -- with the attach point already present, it was an orange circle. Do you know whether or not the stands will be stored within the planes themselves?

Looks like it will be the tail jacking point.

Will be stored at the stations. If the aircraft carried them, there would need to be inspections and MEL changes. Better that the stations have the stands and spares to keep them serviceable.

Quoting T5towbar (Reply 130): Hopefully this will be completed by the end of the month. As far as I know, they will be stored at the station/hub instead of on the aircraft.

Yes, stored at the stations.

Quoting T5towbar (Reply 130): and there is an attach point where to insert it.

Looks like the jacking point for the tail is used.