airbubba

chock/chalk one up for you! ;-)

hand me a colodny burger

Huck,

I fully appreciate what you are saying, however the responsibilty that goes with the job doesn't change. It's a problem that faces us all in this industry - pay peanuts and you will get monkeys.

HalfNut,

That's the difference between an ETOPS aircraft and a non-ETOPS aircraft. ETOPS time certification takes into account that the aircraft could be at the furthest extremity from a suitable alternate when such a critical failure occurs, and systems are subsequently modified to cater for it.

SSR,
Both Airbus and Boeing developed presentations for all operators in the aftermath of that accident. At low to medium airspeeds rudder limiters would not be of much use, as they kick in at higher Indicated Airspeeds.

They highlighted that it is the cyclical input - say full left rudder followed shortly after by full right rudder, creates a moment way above that ever catered for in design criteria.
At the time of that accident I was flying Boeings and subsequently received training, prepared by Boeing, highlighting the dangers of such manoeuvers and how the risk existed to all large transport aircraft.

If I recall correctly, our ETOPS B757's had hydraulic driven generators (HDGs) to take care of the electrics' redundancy. The RAT is a hydraulics redundancy for flight controls alone, per someone's earlier inquiry.

Yes, and this was known many years ago, when the first B707's were introduced.
Oldtimers retire, new guys on the block are in charge of training...lessons learned a long time ago promptly forgotten.:sad:

411A,

Never flew the 707, but my guess is the fear of stomping the rudders in that jet was due to the dutch roll tendencies of it's 1950's design.

With bad feet skills, I think the 707 would be rolling towards the ground sans it's outboard engines long before failure of the vertical stab.

I don't believe the RAT can ever drive the HDG, RAT pressure is limited to the flight controls part of the center hydraulic system. However, there is an Air Driven Pump on the center system that will drive the HDG with pneumatic power if required on ETOPS planes. I'll add the caveat that Boeing has always been somewhat creative with options like extra pumps and switch positions in aircraft made for different customers and different engines so there may be exceptions to my claim that the RAT can't drive the HDG.

Under current ETOPS doctrine I think the acronym for this situation is S.O.L.:)

Actually, there was a Martinair 767 that had some serious hot battery bus problems on a crossing with somewhat similar landing and control issues:

ASN Aircraft accident Boeing 767-31AER PH-MCH Boston-Logan International Airport, MA (BOS)

And you need the aircraft battery as well as the APU battery to start the APU so if the aircraft battery was dead it wouldn't work anyway.

ETOPS aircraft would have to lose both engine generators and the HDG to end up on battery only for 30 minutes. The K106 relay that caused this problem could have done the same. If you start the APU in flight hopefully you will do it before the battery goes dead. It wouldn't have done any good here because both engine generators were working just fine. Standby power loss was the problem because of the faulty relay. Going to bat position gave them back standby power but only for an advertised 30 minutes. Now with no battery charger they lost their standby busses. As far as stabilizer trim some 757's had mechanical cables to the hydraulic valves to control stab trim but most had electrical switches to do so. Apparently they had the switches so elected to land at flaps 20 to have flair capability for landing. No antiskid and other failures caused them to leave the runway a bit but all ended up well.

Having personally flown the 707 for quite a few years, I would agree...outboard engines chucked off the pylons prior to the vertical stab going bye-bye.

More from MartinAir B767 case in May96
 

AirBubba -- GOOD recollection on that MartinAir B767 event (28May96).

Here's more on that MartinAir case (not in ASN's summary quoted earlier):

NYC96IA116

Airbubba:

The B757 & 767 have very different hyd systems. Only the 767 has the ADP on the centre system, that being the "heavy" one, running gear & flaps as well as other things. The B757 hyd is a bit of a mess in comparison, with gear on L system and a PTU to boost the L system in the event of L engine failure.

kenparry,

I think you'll find that the ADP in the C hyd system of the B767 is a bit simpler than that. Think ETOPS - L and R hyd systems EDP + electric demand hyd pump, C hyd system electric pumps (2) + what for demand? Only ADP is left for redundancy unless there is the messy complication of PTU and then from which hyd system?

Perhaps a naive question, however how were the crew of 268 communicating with ATC towards the latter part of the flight when batteries failed?

Quote from sevenstrokeroll:
nocti
it hasn't been proven to my satisfaction.
I've moved the rudder on the 9...it has a limiter and I couldn't shake it apart.
put a limiter on the a300 and you might have something
there was a dissenting view from one member of the NTSB
[Unquote]

Off topic but, since you've raised this one, it needs to be looked at: I'd be very surprised if the A300-600 hasn't got a rudder travel limiter. The A310 had one from service entry in 1983, and the A300-600 is of similar vintage (1984?). If memory serves, the A310 has a comparable (composite) fin and rudder to the A300-600. The A310-200 limiter "reduces the pedals and rudder deflection from ± 30° at speed below 165kt to ± 5° at 310kt and above." [FCOM, 1985]

Am neither engineer nor test pilot, but what Nocti says makes sense. Presumably, the speed threshold on both types would have been reviewed after the A300-600 accident.

AA 757 departed runway at ORD - no injuries
 

On September 22nd an American Airlines Boeing 757 went off the runway at Chicago O'Hare after suffering a serious electrical failure. The generator failed and the pilots elected to continue the flight to JFK on batteries for the next hour and a half even though the manual stated that the batteries would only last about 30 minutes. Only after they lost intercom, trim, and several other systems did they elect to divert to ORD. They discovered the hard way that they couldn't deploy full flap or thrust reversers and the captain had to steer it onto the grass to avoid overrunning. Fortunately there was only minor damage and no injuries but it could have been much worse.

NTSP preliminary here:
CHI08IA292

Not knowing 757 systems I can only speculate on what happened, but it does seem to be a massive error in judgement. Any 757 drivers out there that can add anything?

I just reviewed the electrical abnormals on the 757 and it says going to bat on standby power gives about 30 minutes of operation since the battery charger is inop in bat position. Since both generators were operating normally and the relay failure in auto caused the standby busses to fail, one of the radios not using standby power was still being powered. Check lists don't say to do this but since a different relay controls the battery charger maybe going back to auto for a few minutes might have made the battery charge enough to last for landing. I have thought about what to do in case of a total electrical failure over water and saving the battery for the approach was a high priority. I think the abnormal checklist is being changed because of this incident.

Yep, you're right, the ADP is only on the 76, the original question was about both aircraft, I should have been more specific.

The HDG is on both '75's and '76's if they are ETOPS equipped. As far as I can tell N197AN is not an ER bird, so this wouldn't be a player anyway.

My guess is that, as long as the battery switch was still on, standby DC had enough power through the hot battery bus to supply VHF 1 even though the voltage was too low to run most of the other stuff.

_____________________________

I like your theory better, you're right, VHF 2 should be powered by one of the main buses, it's a wacky situation with a relay fault.

That's why checklists were invented !

The Wright Brothers didn't have a check list, nobody had broken an aeropane at that time. If the new kids on the block are going to re-invent the wheel every 10 years or so, nobody will ever be safe from human error. ( or human misunderstanding of a mechanical problem.)

But wot's new ? Have you ever tried to teach a teenager ANYTHING ! :ugh:

As PanAm discovered over France one day, whilst re-positioning an empty aeroplane ( no pax. involved)

BOAC lost a 707 on Mt. Fuji 'cos the fin broke off first, different forces at play of course, not crew input.

Now that you've mentioned the Belle Harbor crash...
 

Excuse me sir, but do you have at least a vague notion of what the diverging oscillation is? What brought the AA587 down was not sustained rudder input but diverging yaw oscillation caused by handling pilot's excessive, rapidly alternating and completely unnecessary pedalling.

Is the using a rudder to pick up a dropped wing a propper technique on modern transport category aeroplane? Yes - provided there is a complete loss of roll control. If you have only a wake turbulence encounter and all your ailerons and spoilers are working normally - absolutely no. Shortly after NTSB's preliminary report became public, my FCOM was updated with information that primary purporse of the powerful rudder attached to my aeroplane's fin is to counteract yawing moment of live engine when one engine packs up at take-off. It was never envisioned to be used as primary flight control and cycling it might cause structural failure even below Va. Mind you, I was flying ATR-42-300 at the time.

So AA had Advanced manuevering training programme, which involved unusal recoveries from unusal attitudes practised in the simulator. The fact about the simulators is that they are only simulators, they can fairly well replicate aeroplane's behaviour within normal operating envelope but if you're involved in some exotic manuevering, you may put your simulated aircraft in the places where no test pilot has ever dared to go with the real thing - for a good reason. Simulator's behaviour under the circumstances is only the best calculation and estimation of what would happen with the real aeroplane and maybe it's completely realistic and maybe it's totally wrong, there's just no practical way of verifying it.

A300 does have a rudder limiter which worked as designed on the day of the accident and it wasn't redesigned post mortem. As the AA587 accelerated rather rapidly, it was in transition from low speed to high speed position at the time of the fin detachment. Now if it moved to high speed position would it prevent the accident? Maybe it would, or maybe we would see a couple more oscillations before fin separation. NTSB mentions that the way the A300's rudder system was designed was contributory cause, but this is analogue to saying that the tree caused the death of the motorist that smashed into it with 80 mph. He might have survived if it wasn't for the three but the actual cause was high speed road excursion, not someone planting a tree at the exactly wrong place a couple of decades ago.

Does 411a have an anti-American stance? Absolutely, but it is completely besides the point. Every case study he mentioned was reported correctly. He even failed to mention Bradley accident where improper non-precision approach technique, improper use of alt hold and nonchalance about correctly setting the altimeters led to Super80 flying through trees on the final approach. American or non-American, any company whose pilots don't know that battery that just keeps on discharging in flight is land ASAP item on any battery-equipped aeroplane, notwithstanding what their ECAM/EICAS/CCAS/whatever tells them, has some serious training issues.

Yes indeed, and further to your very astute observation Chris, perhaps the old adage 'aviate, navigate, communicate' should be updated to reflect current thinking in many cockpits; 'calculate, documentate, litigate'.