Incident: Swiss A333 at Zurich on Nov 26th 2015, hydraulic failure
 

Single system failure on multiple system aircraft. No one hurt, no damage. nothing to report!
Probably happens several times a month somewhere in the world!

I've had one in an A333 - green system, (for those not familiar, the main system - leak was in the main manifold). Except for one snag, it was indeed a non-event, (manual gear extension, no nosewheel steering, alternate (blue system + accumulator) braking). With slight touches of the left or right brakes, the nosewheel casters sufficiently to clear the runway on a high-speed taxiway so as to not close the runway, (not the highest priority in an abnormal landing of course, but all else being equal, the aircraft can make shallow turns).

Clear the RWY?
Seriously. Would you try it?
I wouldn't.

Well, you weren't there. Do you fly these aircraft; do you know the A330? On a diagonal taxiway it worked smoothly, without effort. Once the tail was clear of the runway, we stopped and requested a tow to the gate. QED.

On the MiniBus you can defer the NWS and fly around with steering by differential braking only for days...
And you say you can't make it into a high speed turn-off?

FDMII: I can echo your experience. I had two Green System losses on the A330 and it is indeed simple to vacate at a high speed turnoff. The second event was on a Base Training detail (ie. no pax onboard ) and we tried to taxy slowly back from the runway. However, if all the fluid is lost from the steering pistons then there is no damping and at low speeds the nosewheel did not continue to castor if you get off line and we found that it tended to "snap" over in the fashion familiar to a supermarket trolley. Therefore a tow back was used.

Of interest, I once witnessed a Thai B747 land with a SYS1 HYD failure ( ie. no nosewheel steering + other faults ) Not only did he clear the runway but he taxied all the way to the stand + parked there using differential brakes. My jaw dropped!

That's indeed very skillful, and certainly can be done. I considered it but had no fluid left and the castering wasn't working for the sharp turns needed.

In our own event, the "but" implied in the first post was a really odd event that occurred during the ECAM procedure. The ECAM checklist was carried out but the moment the Green system pumps were selected off, the HYD B RSVR LO LVL ECAM message came up, requiring a shut-down of the Blue system pumps...

As I said, not really newsworthy other than Pax not where they wanted to be.

I had a dual hyd. fail on an A300. Green and Yellow, although yellow was servo jam so we still had flaps and alt. brakes. We upgraded from Pan Pan to Mayday only because the Milan controller would not stop talking to us while we ran the check lists.
Landing was normal but we got towed in as there was no steering.

I had the same with a DC8, 20 years ago or so. On this acft there's a single hydraulic circuit with a priority valve that allows hydraulic flight controls to be activated even with some hydraulic leaks.

Ourselves, we lost up to the last drop of skydrol on board... Servo-tab flight controls (hence DC = "Douglas Cable", or "Diesel & cable":) ) at FL390, not much a matter, electrical back-up horizontal stabilizer setting, and.... one of my very best landings with that workhorse.:ok:

Then normal use of thrust reversers (pneumatic moved on the Jurassic Tube JT3D), and finally easy exit on a high-speed turnoff with differential braking, using brake pressure accumulator to bring the aircraft to a full stop.

A total non-event.

Then we just asked a tug to taxi in...

Homebuilt - good story - hat's off to you -an almost-complete hydraulic loss on the '8 is more significant than loss of the green system on an Airbus, (A320/A330/A340 series). Well done. How heavy were the controls?

Cable-driven servo-tabs on the ailerons/elevators, electric trim for the horizontal stab, and cable-driven rudder and the aux pedestal by the oiler's panel behind the F/O that had an Alternate Hydraulics lever..., IIRC? - loved the airplane.

Thank you!

Wasn't writing this thinking I deserve any congrats...;) Indeed we had been trained for that during the type rating. Flying a DC8 (and I guess a DC9/MD80 that seems to be using the same technology) without hydraulic isn't that tricky. Servo-tab technology allows low effort handling on flight controls. Indeed you only move tabs that must have the same surface than a Cessna 172's aileron or elevator. And these tabs themselves move the big 8's elevators, ailerons and rudder.

Simply, there's a little bit more inertia, that's why we were taught to move flight controls with a "staccato" style motion: moving them, block them and wait for matching aircraft response. And that works well..:ok:

And indeed, I also loved that good old Douglas.. :)

:ok:

CP

"Wasn't writing this thinking I deserve any contrats..."

I know; - spoken as a true professional.

We need to pass that quality on to those coming up behind us... ;-)

Cheers,

:ok::ok::ok: