Hudson Bus

[speedbird591]

Hi Leif. I've never even heard of explosive bolts and it's not what I meant. In all the BOAC/BA Boeing ditching drills I did in my 30 years (707s, 741s, 742s and 744s) the SEP (Safety Equipment and Procedures) manual made it clear that the engines/pylons are designed to shear off when they hit the water. It's not something I've made up - it's a basic safety procedure assumption that on a Boeing the engines will not be encumbering the flotation and evacuation of the aircraft. The Flight Crew used exactly the same SEP manual as Cabin Crew. I was just surprised that Airbus had come to a different solution to Boeing and that it doesn't seem to have worked.

Out of interest, the VC10 was different, naturally, in that the assumption was that the engines would still be attached but probably damaged. For that reason we could only launch liferafts from the end of the wing in case they were damaged by torn metal. A rope had to be attached to a ring on the outer part of the wing and the liferafts attached to that with the inflation cord. The passengers would then walk out to the end of the rope to board the liferafts. Although there wasn't much confidence amongst the intructors that the aircraft would stay afloat for long with four Conways attached to the rear!

Ian

[DispatchDragon]

Dave you win
All fluids all sparks oh yes and in tail mounted aircraft the crossbleed valves to prevent the fire spreading to the other
engine or engines

Ian

Sorry mate , I wasn't aiming at you, its just the "exploding bolts" legend keeps rearing its head, so I thought I would
put it to rest given the oppurtunity. The shear points on Boeing I was aware of - in fact it was that which caused the
Air France 707 to deposit a pod in Provence - It experienced severe turbulence and one of the Pods exceeded the
lateral movement that Boeing designed and departed the aeroplane. In the Airbus (and 737 for tha matter) systems
training classes that I have attended over the years they always taught ditching holding the attitude as nose high
"as long as Possible' to keep the engines out of the water.The logic being that you would keep those two bloody great scoops
out of the water However they never mentioned what would happen once they were in the water. Capn Sullenberger did just that, As I said I will wait till the NTSB finishes its work and read the report. It will be interesting from an engineering stand point to see their findings.


Leif

[TobyV]

I'm an engineer, albeit not in the aero industry. I'm not sure i'd want anything going "bang" anywhere near wings full of fuel, or worse still, fuel vapour. Not only that, but as every action has an equal and opposite reaction, the explosion might well at the very least damage systems (like hydraulics or electrics) or worse still distort the wing structure or the previously mentioned high lift devices.

I would have thought the best way to do it (and maybe if/when the NTSB make any data or plots from the FDRs available, we'll see how Capt. Sullenberger did it) would be to near-enough bring the aircraft into a stall jsut above the water. Minimum forward airspeed, maximum incidence to try and "plop" the engines into the water and minimise the "digging in" effect which you would have thought would cause a sharp moment nose-first into the water.

Its an interesting question - not one I'm sure that FS would quite let us try out yet (with any "true" physics behind it?).

Can anyone on here (thinking mainly RAF tecchy guys) describe the mechanism that jettisons drop tanks? I would imagine its purely mechanical and relies on gravity or a small amount of postive G applied to the aircraft at the moment of release?

[TSR2]

As I said, it was explained to be when I was eleven, so probably someone who didn't want to explain shearing forces to an inquisitive 11 year old

[DispatchDragon]

LOL Sorry Ben

I was more interested in how the "Legend" got started, Ive heard it several times on FS forums.
and the only explanation I could come up with is the one I stated - about the squibs used in the fire supression system
which actually do go bang - like a penny banger (oops Im dating myself)


Leif

[TSR2]

No worries Leif.... It doesn't make any sense at all, but I remember there was an old 707 sitting on the ramp minus the engine with 3 or 4 orange tipped bolts hanging down from the pylon, so I asked him why they were tipped orange.... I think by that stage he was wanting to go home! (we had spent an hour in the cockpit of EI-ANG with me asking loads of stupid questions)

You can just make out the 707 behind the 747SP. From memory it was untitled, but had the blue top with a dark blue stripe like KLM, but I didn't think KLM operated the type.

[speedbird591]

A couple of interesting pics I've found on the interweb that are related to this subject. But I hasten to add that they're not intended to prove or disprove anything!

Both aircraft landed unintentionally 4-5 km short on the approach to runways and had their gear down. The DC-8 (1968 SFO) retained it's engines, didn't sink and was salvaged to fly again. The 707 freighter (2000 Lake Victoria) lost it's engines and didn't sink. It was towed to the shore and apparently is still there in Lake Victoria. No deaths or injuries in either incident.





Ian

[DispatchDragon]

which only goes to prove Douglas ALWAYS built em stronger than Boeing

Four nifty photo's there - its funny in my career thats one airplane I HAVNT flown on (The SP) yet in the other
photo I have flown in all three types and one of them the specific aircraft (guess which one)


Leif

[TSR2]

Well if its not the SP, I would have guessed the DC8?

[DispatchDragon]

Nope the 44 in your other photos in the Gallery - once cadged a lift back from AUH in it

Leif