Do VA planes sometimes tip over?

[The Rok]

Maybe they did, but they certainly wern't as upfront about it. I remember being in row 3 and standing at the L1 door shortly after the seatbelt sign turned off.

But I don't think there was a crew member in the past standing behind row three stopping all Y pax from disembarking? Am I getting my thoughts mixed?

They never allowed PE PAX to disembark. They held everybody until the rear stairs was in place and PAX from the rear had started getting off. The reason given in the OP was also given to me numerous times. Trust me I asked almost every time why we had to wait and always got the same response.

 

[elbarto]

Sounds like someone is feeding the crew bs. While it is known that poorly distributed weigh can cause an aircraft to tip, I don't believe this is likely to be causes by pax boarding and disembarking as the bulk of airlines board through front doors. The tipping usually happens to cargo jets when they move the pallets around and have to put a stand under the tail to prevent it from tilting.

You don't see this too often do you?




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[medhead]

Just to drag out one of my old war stories. One day on either a metroliner or Saab 3?? from OLP to ADL we were asked to let the pax at the rear get off first because tipping could be a problem. In this case the rear cargo area was full of TV camera gear. Given the small aircraft size I thought it sounded reasonable.


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[eastwest101]

Metro tipping rearwards with full cargo - entirely possible. 737 tipping forwards or backwards due to pax - complete BS

 

[Awesom Andy]

Just for the sake of it, we should all get on to a flight, and at the destination when they are trying to attached the rear steps, all of us would run to the front or rear of the plane, and start jumping up and down.

 

[ash.1111]

Procedure is for passengers to start disembarking off the back in a continuous flow (and reach the bottom of stairs) before front Y pax walk off. This is due to possible damage from the back stairs on 800s when front and rear disembarkation active.

Also, PE used to have to wait with the rest of the passengers.

 

[oliverd]

Just for the sake of it, we should all get on to a flight, and at the destination when they are trying to attached the rear steps, all of us would run to the front or rear of the plane, and start jumping up and down.

I'm in

Also, PE used to have to wait with the rest of the passengers.

In this case, J passengers (2, I think) were allowed to disembark several minutes before everyone else.

 

[Fruitcake]

Sounds like someone is feeding the crew bs. While it is known that poorly distributed weigh can cause an aircraft to tip, I don't believe this is likely to be causes by pax boarding and disembarking as the bulk of airlines board through front doors. The tipping usually happens to cargo jets when they move the pallets around and have to put a stand under the tail to prevent it from tilting.

You don't see this too often do you?

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Aircraft aren't seen standing on their tales too often because it's an expensive, dangerous mistake to make and the risk of having it occur is therefore managed. Just as correlation does not equal causation, infrequency probably does not indicate improbability!

 

[koonyaflyer]

Procedure is for passengers to start disembarking off the back in a continuous flow (and reach the bottom of stairs) before front Y pax walk off. This is due to possible damage from the back stairs on 800s when front and rear disembarkation active.

Also, PE used to have to wait with the rest of the passengers.

It was certainly my experience that when travelling in PE the CS would look out the window for a certain number of people to disembark from the rear prior to letting pax forward to disembark.

Now, Business disembarks, and I notice that there is often quite a delay before forward Y disembark, so assume that balance is a consideration.

 

[SeatBackForward]

Perhaps a tongue in cheek reference to the girth of J-Class?

 

[Boof1]

Guys this is nothing to do with the aircraft type or airline and everything to do with the ground equipment. The opening post mentioned this was at SYD. The aircraft would have been connected to the aerobridge which has the ability to regulate it's height against the rise and fall of the aircraft's height as the weight is loaded or off loaded (it's the little wheel you see to the right of the air bridge that rides up and down the side of the fuselage as you board). You know the air bridge is compensating when you are boarding and it drops a bit when you stand in the bridge tunnel!

The rear stairs however are generally not automated and are often either adjusted for boarding and deplaning or are simply set up lower than the doors hence you step up and into the aircraft. This is especially the case for the welded stairs that VA and JQ use.

The reason that this happens, and the reason VA are doing this is so that the rear stairs that are parked do not break the door ( or the slide mechanism). In a worst case scenario as the passengers deplane from the front with the rear stairs connected, the weight shifts aft, the back of the aircraft lowers as the nose rises and the door mechanism rests on the stairs. As the rear lowers further the door or the slide breaks and then you have an aircraft that is out of action for sometimes weeks.

QF don't have this problem as they use the forward stairs only in general. With VA or JQ if you deplane or board at a remote stand this isn't a problem as the aircraft lifts on the gear oleo's at an even rate as passengers deplane forward and rewards at an even rate. It really only occurs at ports that use both rear stairs and the aerobridge system.

For what it's worth a few extra minutes in the aircraft is a damn sight better than a broken airplane and potentially hundreds of thousands to fix. Google the United A320 that had the door break due to the aerobridge rising in error a few years ago if you are interested in what can happen, it broke the door at the bottom hinge and required significant repair to the door and fuselage at huge cost to the airline.

Cheers,

Boof

 

[AVC]

I'm sorry Boof, this still makes no sense.

Correct me if I'm wrong.

They want to avoid the tail of the aircraft lowering onto the stairs yes? No problem with that concept.

But if they deplane the forward cabin, and hold the rear cabin from deplaning, this will cause the CoG to shift aft, exacerbating the problem.

If they deplaned the J PAX (from the front) and then allowed the forward rows to exit (via the front door) this will keep the cog from shifting aft. Any PAX heading towards the rear stairs are going to move the CoG aft, ergo the tail will lower.

If the Y PAX deplane aft (and/or forward) at the same time as the J PAX deplane forward it would balance out.

If anything the rear cabin should be deplaned first.

 

[Fruitcake]

If the Y PAX deplane aft (and/or forward) at the same time as the J PAX deplane forward it would balance out.

If anything the rear cabin should be deplaned first.

That's exactly what the FAs are doing. J pax are allowed to exit (presumably as a benefit for pax who pay for expensive tickets) whilst the rest of deplaning is delayed until the process can be carried out reasonably consistently from both ends. I assume that letting J pax free first is deemed to be well within the margin for movement. The situation they're trying to prevent is rows 1-12 being empty whilst rows 25-30 are piling into the galley waiting for the back door to open.

I'm guessing the crux of the problem is that one can dock the jetway and get the front door open quicker than the amount of time it takes for the engines to be safely shut down and the rear stair rolled in.

 

[Boof1]

Fruitcake has the idea. The CoG is somewhere near and forward of the main gear in most cases, with pax deplaning from either end it keeps the CoG nearer to the middle of the aircraft. Given that a full 737 only has 8 J pax this is acceptable as the aircraft can sit on the ground with J empty no problem. The issue is when the pax in rows 4 through 13 who are sitting over the CoG start to move to the rear or they move out the front with all the rear pax still on board again shifting the CoG rearwards.

Also don't forgot that down below the cargo holds are being unloaded as well which will effect the weight shift. By keeping the forward Y rows from deplaning quickly out the front the CoG will remain within the correct range.

Cheers,

Boof

 

[medhead]

Of course if rows 1-12 are empty and 25-30 are in the galley waiting, where are rows 13-24 going to be? Certainly not standing there stating blankly into space I dare say they'll have moved forward.


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[Fruitcake]

Of course if rows 1-12 are empty and 25-30 are in the galley waiting, where are rows 13-24 going to be? Certainly not standing there stating blankly into space I dare say they'll have moved forward.


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Sorry, I was trying to pick extremes. But my thinking is that if you're in row 13, on average, you can't step into the aisle until the last window pax from row 12 has done so. At that point you've got (say) 15 people moving forward through the aisle to the door. But at landing, 72 people were sitting in that space. Pax can't move forward six-abreast and stream into the terminal together, especially once you consider the delays caused by things like window pax stopping to retrieve overhead baggage. So the CoG (assuming cargo holds are untouched through this process) will slowly move backwards as occupancy of the front of the cabin thins out.

 

[AVC]

Mmmm OK, that sort of makes sense.

But why not just use the front door for everyone? Problem solved. Or let everyone stream off the front door until the rears stairs are in place.

If the PAX can't move forward 6 abreast, then it would stand to reason that they couldn't move rearward 6 abreast either. You're not going to pile 50 PAX into the galley if they can be streaming off the front.

 

[UP4014]

Sounds like someone is feeding the crew bs. While it is known that poorly distributed weigh can cause an aircraft to tip, I don't believe this is likely to be causes by pax boarding and disembarking as the bulk of airlines board through front doors. The tipping usually happens to cargo jets when they move the pallets around and have to put a stand under the tail to prevent it from tilting.

You don't see this too often do you?

View attachment 6466

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Or a bit closer to home.
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