Thie biggest problem with it all is that airline management, including AA, want an on time flight, and will take chances like this in this example. Also most of the airports that you listed does not have AA mechs. so that would have been another expense getting mechs. to the aircraft if it had landed in one of them. Also AA management does not want to give up the revenue that was on the flight to other airlines in order to get them to there destintions. So, in short, it all falls back on management for being so greedy. You can tell that by the ones that posting here talking about it. Sure ORD worked out fine this time, but what about next time. Does AA need to lose an aircraft, and the the lives of nearly 200 people to save, or make a dollar? Someone here was acting very greeting and I would bet it was the management person on the ground in his nice office barking orders out the the crew.
Flt 268 SEA-JFK diverted to ORD, off runway into grass
- Thread starter FWAAA
- Start date
You're missing my point. What I'm trying to convey to you is that, HAD THEY KNOWN they were down to only battery power, they would NEVER had continued the flight for so long.
Why they didn't realize it remains the question. One of my theories is that they may have thought they were in an ER, which has an HDG (hydraulic driven generator) that will continue to power the electrical system in case of loss of main AC power.
Again, eolesen... no pilot would ever knowingly fly that long on batteries only.
I'm thinking your over rating management’s influence on either flight safety or an aircraft's maintenance…… bro!
Managements "request" has really no bearing on my decisions, that I sign for, ensuring and aircrafts airworthiness...................... PERIOD....... Not even debatable…
My license, My signature!!!!!!!!!!!!
Now a little system knowledge on the RAT.
The 75 RAT, whether it’s domestic or er does not provide electrical power.. Only center system hydraulics pressure. No Volts, No Freqs.. Nada.. Nothin!
To correlate this to this incident. I say these pilots were more lucky than skillful.
The Rat is armed above 80 kias via a Q Speed switch.. In the event of a “double engine†failure, the rat will automatically deploy. The pilots can manually deploy the rat via and overhead deployment switch.. The problem is “both†deployment techniques require power potential from the 28 Volt DC Batt Hot Bus… Without that power.. No deployment will occur..
In this case, if the engines fuel supply, which is now being sucked in by the mechanical pump, failed to deliver. And the electric pumps that feed the engine mechanical pumps are now inop. The engines quit.. We now have a 757 glider that is incapable of rat deployment, 0 psi on hydraulics other than a wind milling engine hydraulic pump, with complete flight control failure.. Absolutely nothing..
As the manual states: “there is no reversion to manual flight control in the event total loss of hydraulic pressureâ€
So, where’s your bet.. Luck or Skill?
Managements "request" has really no bearing on my decisions, that I sign for, ensuring and aircrafts airworthiness...................... PERIOD....... Not even debatable…
My license, My signature!!!!!!!!!!!!
Now a little system knowledge on the RAT.
The 75 RAT, whether it’s domestic or er does not provide electrical power.. Only center system hydraulics pressure. No Volts, No Freqs.. Nada.. Nothin!
To correlate this to this incident. I say these pilots were more lucky than skillful.
The Rat is armed above 80 kias via a Q Speed switch.. In the event of a “double engine†failure, the rat will automatically deploy. The pilots can manually deploy the rat via and overhead deployment switch.. The problem is “both†deployment techniques require power potential from the 28 Volt DC Batt Hot Bus… Without that power.. No deployment will occur..
In this case, if the engines fuel supply, which is now being sucked in by the mechanical pump, failed to deliver. And the electric pumps that feed the engine mechanical pumps are now inop. The engines quit.. We now have a 757 glider that is incapable of rat deployment, 0 psi on hydraulics other than a wind milling engine hydraulic pump, with complete flight control failure.. Absolutely nothing..
As the manual states: “there is no reversion to manual flight control in the event total loss of hydraulic pressureâ€
So, where’s your bet.. Luck or Skill?
E.
They had two engine driven generators and an APU generator. All the references in the manuals and checklists and most of the armchair experts here and elsewhere are referring to a situation where an aircraft is down to the battery as the LAST REMAINING source of power.
I reviewed to checklist procedures they had to deal with too. All of the items listed as going inop from lost of the
AC/DC bus are defferable by the MEL. Every day we have aircraft flying with stuff inop on that list. The problem is that now it seems there are a few more serious losses from those busses that are not listed in our pilot manuals or procedures. An example is the flight control problems. No hydraulically controlled aircraft should have controllablility problems due to loss of a single electric bus, especially a battery bus.
Right now, both you and Jager rank numbers 2 and 3 out of a scale of 100 regarding accuracy on this thread. This comes from 5000+ hours on the 757/767.
P.S. twaokc's comment regarding management influence is a non-issue despite their increasing assaults on pilot decisons.
lpbrian
Veteran
- Mar 7, 2004
- 687
- 105
Not entirely correct. It is true, a 757 RAT will only deploy if both engines fail. It is also true that a 757 RAT only provides center system hydraulics for basic flight controls only. It is also true a RAT powers an HMG (hydraulic motor generator) for main battery backup, on ETOP's A/C only. It is not true there is a manual RAT deploy switch on a 757, like there is on a 777. In looking at some posted pics, it looks like said A/C is 5FG. this is a recently delivered 757, and I think this A/C has ETOP's equipment. looking at the pictures also shows the RAT not deployed. As it should be..
lpbrian
Veteran
- Mar 7, 2004
- 687
- 105
But the engines did'nt quit, therefore both L/H and R/H hydraulic systems were both pressurized. Thus, you had both normal, alternate and reserve braking and nosewheel steering. Alternate gear extend has it's own battery pack. T/R's thus had no power to unlock and spoilers were inop, otherwise, you still have brakes... The Boeing boys ain't dumb ya know....
IpBrian...
The info I've posted is directly from the 75 maintenance manual.. I'll check on that alternate gear extension "battery pack" when I get back to work.. I never heard of it but it might be.. I thought it was cable actuated to free fall.
Also I said "IF" the engines quit from fuel starvation, the crew would have been screwed.
Luckily the engine driven fuel pumps worked in conjunction with gravity feed..
and you know it...........Boeing builds the best aircraft in the sky...
The info I've posted is directly from the 75 maintenance manual.. I'll check on that alternate gear extension "battery pack" when I get back to work.. I never heard of it but it might be.. I thought it was cable actuated to free fall.
Also I said "IF" the engines quit from fuel starvation, the crew would have been screwed.
Luckily the engine driven fuel pumps worked in conjunction with gravity feed..
and you know it...........Boeing builds the best aircraft in the sky...
It wasn't by "luck" or just by accident that Boeing designed the B757 feed fuel with just the engine driven pumps (or just about every plane since the Wright Brothers).
For the lurkers:
Jager fits the perfect description of the saying "a little information is dangerous". If I had a major problem in a 757 inflight, I'd bring up deadheading pilots or mechanics up front for possible input in dealing with a solution. Initially, I would feel fortunate to have a mechanic onboard with some 757 systems knowledge like Jager, but if he sounded anything like he has on this thread, I'd send him back to his seat quickly.
Well yes and no. Management can and has changed the standards of airworthyness such as when they used to ground A-300s on ER trips because of ice in the fuel tanks, however once the delays became excessive they removed sumping from the ER check. Recently they have sought to change the standards as far as addressing lightning strikes. Not checking doesnt fix the problem, it just keeps it from being discovered. Many years ago Management decided to change the proceedure for DC-10 engine removal in order to save time which eventually led to failures of the pylon and we know where that led. So what is considered airworthy from a maintenance standpoint can change, we have to go by what the book says. So I dont doubt for a minute that what Mach85ER says is possible, they may have followed the book and that may have led them astray. Its happened to mechanics and we have the luxury of hashing it out on the ground.
To me the primary focus should not be so much as to what the pilots did or didnt do, after all nobody got hurt, I'd like to know how he ended up on battery power. If it was just from the failure of a single relay then clearly the system lacks redundancy. I wouldnt want to trust those batteries, not even for 30 minutes, years ago they were regularly maintained in shops like the one we had at JFK, now they just sit in the stockroom until they are needed.
lpbrian
Veteran
- Mar 7, 2004
- 687
- 105
IpBrian...
The info I've posted is directly from the 75 maintenance manual.. I'll check on that alternate gear extension "battery pack" when I get back to work.. I never heard of it but it might be.. I thought it was cable actuated to free fall.
Also I said "IF" the engines quit from fuel starvation, the crew would have been screwed.
Luckily the engine driven fuel pumps worked in conjunction with gravity feed..
and you know it...........Boeing builds the best aircraft in the sky...
My bad. I checked, the alternate extend system runs off the hot battery bus. Whatever, the crew lowered the gear in time. Scary....
