Don't rock the plane!

[jugofpropwash]

British Airways landing gear not down correctly, passengers told to disembark slowly and not rock the plane?

Terrified British Airways passengers told 'don't rock plane' after jet makes emergency landing at Heathrow (http://www.msn.com/en-ie/news/world/terrified-british-airways-passengers-told-dont-rock-plane-after-jet-makes-emergency-landing-at-heathrow/ar-AAj0fjX)

[DirtyProp]

What about the boat?
:}

[Dont Hang Up]

Old news rewarmed because the report is out.

Amusing to see the journalist quoting excerpts without really understanding the context.

[OldLurker]

AAIB report doesn't mention the 'terrified passengers':

AAIB investigation to Boeing 747-436, G-CIVX (http://www.gov.uk/aaib-reports/aaib-investigation-to-boeing-747-436-g-civx)

[DaveReidUK]

One thread on this topic deleted by the mods a couple of days ago.

Be interesting to see how long this one lasts ...

[PPRuNe Towers]

The person who started the thread deleted it after you posted Dave.

Rob

[Chronus]

Should have used the chutes and not forced the trembling passengers to slowly tip toe their way out of a precariously balanced airplane.

[Hotel Mode]

You haven't really thought that one through I don't think.

What's more likely to destabilise the aircraft, an emergency evacuation down the slides with hoards rushing randomly at the exits, or a controlled gradual disembarkation?

That's before the inevitable multiple injured parties in a wide body evacuation.

[jugofpropwash]

Given that the usual method of disembarking involves everyone jumping up and digging in the overhead for their bags before the plane even stops moving, I'd love to know what the flight attendants told the passengers to ensure a careful, orderly exit.

[broadreach]

You've got a few hundred tons perched - somewhat uncertainly - on a few spindly things with wheels at the bottom end. The spindly things are electrically and hydraulically kept in place and the readings on the electrics and the hydraulics are iffy. Damn right you want the passengers to tread carefully. Methinks whoever the BA crew were, they may have had some personal experience on DC-4s or similar types.

[YRP]

My respect for the author of the article was HALVED about 5 paragraphs in. :)

[NSEU]

After the aircraft was towed to the apron, passengers were told to disembark very slowly....otherwise the aircraft would tip over and settle on its tail," said the official report

This is only likely if the body gear had not extended. Someone was confused.
Lateral stability on turns, etc, might be an issue... but speed of passenger movement? Hardly.

[PAXboy]

Confused or not, no one is going to take a risk. If you get the pax to walk slowly - without their bags - from the rear you have the most chances of a good outcome. If you ask the pax to move slowly and carefully - you will be able to convey the seriousness of the situation. You would have to be VERY sure of where your CofG is and how much your pax weigh before risking a standard disembarkation. I sit to be corrected.

[Basil]

This is only likely if the body gear had not extended. Someone was confused.
Lateral stability on turns, etc, might be an issue... but speed of passenger movement? Hardly.
Concur. I don't have an abnormal checklist to hand but ISTR that the body gear is aft of the wing gear.
Nevertheless, I'd do what it says in the checklist.

[tdracer]

From the 747-400 AFM:
In the event one main landing gear cannot be extended, land with all
other landing gear extended.
In the event neither body landing gear is extended, the airplane may
tip tail down when on the ground. Under this condition, the escape
slides at main doors 1L and 1R will be unusable.
The GEAR OVRD switch should be used to prevent the siren aural.
After landing with one or both wing gear not extended, turn the
airplane on the ground only at slow speed.

[Fursty Ferret]

The spindly things are electrically and hydraulically kept in place

To be fair once they're down they're actually held in place mechanically. The problem in this case appeared to be that of getting them down due to mis-rigging of the landing gear lever unit.

[NSEU]

To be fair once they're down they're actually held in place mechanically.

It may be best to consider that (normally) they are held in place with both mechanical and hydraulic means. Mechanical = overcentered side struts and bungee springs. Hydraulic = downlock actuators. As engineers, during tows, we didn't rely on either of these. We used pins to lock the struts.

[EEngr]

"the airplane may tip tail down when on the ground."

But isn't this exactly when you'd want all the SLF to crowd toward the front? That last fat guy disembarking could be a problem.

Now I can't get the ending of The Italian Job (original movie) out of my mind.

[Airclues]

The quote by tdracer is rather confusing as it refers to both body gears stuck up, which was not the case in this incident. There are also several factual errors in the newspaper article.

The problem in this case was that the gear lever would not move from the 'up' position to the 'off' position which depressurises the landing gear hydraulics. Therefore the landing gear was continuously being pressurised up. If they were to freefall the gear then the hydraulics would simply raise it again.
The body and nosegear use hydraulic system 1 and the wing gear system 4. The problem is that the brakes use system 1 and 4 and therefore you cannot depressurise both. The drill is therefore to depressurise system 1 and then freefall the body and nosegear. They were not taken by surprise when the wing gear failed to come down as the article implies as they knew this would be the case as part of the checklist.

With the nose and body gear down the aircraft will not tip onto its tail as the body gear is aft of the wing gear. It is however laterally unstable due to the narrow track of the body gear.

[Basil]

Airclues, thank you for the definitive answer.
Manual to hand or memory? ;)

[Airclues]

Memory......although rapidly fading!