Ask The Pilot

[jb747]

Blocking coughpit access is the norm on aircraft with forward galleys, and toilets next to the coughpit. It's long past time that those toilets were incorporated into the coughpit.

 

[Boca68]

Blocking coughpit access is the norm on aircraft with forward galleys, and toilets next to the coughpit. It's long past time that those toilets were incorporated into the coughpit.

Thanks JB, I just found it unusual in as much as I'd not experienced actual blocking with a trolley. I understand the potential security aspects. But, I'd be interested if QF has an actual policy on this for International?

As I said, first time I've experienced an actual physical barrier. Immediately after it occurred , all I kept thinking about was how many times I'd been waiting for the bathroom and a pilot/co-pilot comes out. No thought of barriers or holding at a distance.

Understand if you are unable to comment directly on potential security issues.

 

[andmiz]

The cables move the servo controls. There would be far too much load for a directly activated cable or pulley motion.

The 747-8 still has the original 747 control systems. It has fancy engines and coughpit, but other than that it's 50 years old.

FYI to clarify, some of the -8 is fly by wire and its most significant change is its wing. In essence the wing is a larger version of the 787's, with slightly smaller 787 engines.

 

[jb747]

FYI to clarify, some of the -8 is fly by wire and its most significant change is its wing. In essence the wing is a larger version of the 787's, with slightly smaller 787 engines.

Obviously the engines...but which channels beyond that?

 

[andmiz]

Obviously the engines...but which channels beyond that?

Outboard ailerons and spoilers are FBW. Flare assist, yaw assist, manoeuvre load alleviation were added.

 

[jb747]

Outboard ailerons and spoilers are FBW. Flare assist, yaw assist, manoeuvre load alleviation were added.

That's interesting. Quite the hybrid. It would seem to be part way to an FBW system, in that it has partially done away with solid connections, but not taken the step to computer control.

Load alleviation is a common feature. Yaw assist? Engine out behaviour? And what does flare assist do for you?

 

[mannej]

Here is some viewing for you JB747...

ASN Aircraft accident Airbus A321-231 TC-JMM Istanbul-Atatürk International Airport (IST)

 

[Captain Halliday]

I need relation to the 3U aircraft that lost its windscreen at FL330: Another window gone... I note it could only get down to 24,000 initially due to terrain.

Are there locations/regions where high terrain would cause a significant delay in a descent?

Could such a delay potentially exceed available pax oxygen supply?

Does the flight crew have a larger oxygen supply? Bigger bottles, or just more of them?

 

[PLANT]

So family did not know until boarding that they new the pilot flying the plane....... Can the pilot bump you into business from economy reward ticket?
Asking is it ever done, totally against airline policy or not discussed shhhhh

 

[jb747]

Here is some viewing for you JB747...

I suspect I've made my feelings about Asiana known previously.

 

[jb747]

I need relation to the 3U aircraft that lost its windscreen at FL330: Another window gone... I note it could only get down to 24,000 initially due to terrain.

Are there locations/regions where high terrain would cause a significant delay in a descent?

Yes, many. This event happened within what is the classic example.

Could such a delay potentially exceed available pax oxygen supply?

No. That's a planning limit. Escape routes have to be developed that allow a way out at all times. They don't necessarily allow descent to 10,000 feet, but they must do so within the limits of the passenger oxygen supply.

Bear in mind, that depressurisations never actually happen.

Does the flight crew have a larger oxygen supply? Bigger bottles, or just more of them?

Than an individual passenger? Way more. The 747 has 13 bottles available for the passengers. There are two bottles (of an identical type) available for the flight deck. The masks are also much more efficient, and are capable of pressure breathing.

 

[jb747]

So family did not know until boarding that they new the pilot flying the plane....... Can the pilot bump you into business from economy reward ticket?
Asking is it ever done, totally against airline policy or not discussed shhhhh

What?

Not a chance. Upgrades are computer controlled before boarding. People may be moved by the crew for all sorts of operational reasons, but looking after friends or relatives does not apply. Given that the potential cost is your job, you’d have to be very game.

 

[flyer89]

JB,

Over on the old rumour mill there is talk of the A380 doing SYD-JNB at some point, I assume after the queen goes. Any pragmatic considerations that jump out at you immediately?

 

[jb747]

Over on the old rumour mill there is talk of the A380 doing SYD-JNB at some point, I assume after the queen goes. Any pragmatic considerations that jump out at you immediately?

There are no practical issues with the 380 on that route. As I understand it, what was one of the intended routes for the 8 that won't be delivered. It won't be a route that I'll ever fly.

 

[lastrow]

I'v just been watching a TV doco regarding a problem with a Lauda 767 where reverse thrust was suddenly deployed at high altitude and full speed caused when two control valves opened simultaneously. The aircraft became uncontrollable and unfortunately went down. As a former 767 pilot do recall this incident and steps taken to avoid a re occurrence?

 

[jb747]

I'v just been watching a TV doco regarding a problem with a Lauda 767 where reverse thrust was suddenly deployed at high altitude and full speed caused when two control valves opened simultaneously. The aircraft became uncontrollable and unfortunately went down. As a former 767 pilot do recall this incident and steps taken to avoid a re occurrence?

It shouldn't have happened the first time around. As I recall, they'd actually been getting EICAS messages for quite a while, but had been writing them off. The system was unlocking, but the other protections were stopping it from operating. Eventually that didn't happened, and the reverser deployed. Unlike a ground deployment, it actually did so at a high power setting. The upshot was that the disturbed airflow basically killed most of the lift on the wing, and the aircraft rolled. The system did automatically reduce the power to idle, but too late to be helpful. Apparently it could be controlled if you were quick enough, but the window was only a couple of seconds wide.

The manual says this:

Each engine has a pneumatically actuated fan air thrust reverser. Reverse thrust is available only on the ground.

The reverse thrust levers can be raised only when the forward thrust levers are in the idle position. An interlock stop limits thrust to idle reverse while the reverser is in transit.

The EECs control thrust limits during reverser operation.

When the reverse thrust levers are pulled aft to the interlock position:
• the autothrottle disengages;
• the auto speed brakes deploy.

When the reverser system is activated:
reverser isolation valve opens allowing the reverser translating sleeves to pneumatically move aft;
the fan flow blocker doors rotate into place to direct fan air through stationary cascade guide vanes;
the reverser indication (REV) is displayed above each digital N1 indication (REV is displayed in amber when the reverser is in transit).

When the interlock releases:
the reverse thrust levers can be raised to the maximum reverse thrust position
the REV indication changes to green when the reverser is fully deployed.

Pushing the reverse thrust levers to the full down position retracts the reversers to the stowed and locked position. While the reverser is in transit, the REV annunciation changes colour to amber. The thrust levers cannot be moved forward until the reverse thrust levers are fully down. When the reverser reaches the stowed position, the amber REV annunciation disappears.

Each thrust reverser is automatically protected against unintentional reverse thrust. If an uncommanded thrust reverser movement is sensed, an autostow feature automatically applies pneumatic pressure to stow the reverser.

The EICAS advisory message L or R REV ISLN VAL is displayed and the REV ISLN light illuminates when a fault exists in the reverser system.

The light and message are inhibited in flight.

An electromechanical lock prevents uncommanded reverser deployment in the event of additional system failures.

 

[lastrow]

Eventually that didn't happened, and the reverser deployed.

Thanks for another detailed reply jb . It is strange that the prevention system finally gave way and deployment resulted. According to the presentation I saw mechanical locks were installed to prevent any malfunctions in the hydraulic system causing this situation to occur again. The manual is very detailed however as the presentation said (and you also observed) you only have seconds to put things right. Do you ever face this situation in your SIM training?

 

[jb747]

I think I saw it during FO training on the 747 Classic. The issue though, was that the sims were not simulating it correctly. It was much less controllable in the actual aircraft, especially if the translation occurred at a high power setting.

 

[tuppaware]

I think I saw it during FO training on the 747 Classic. The issue though, was that the sims were not simulating it correctly. It was much less controllable in the actual aircraft, especially if the translation occurred at a high power setting.

Begs the question, before the days of computer simulations how did aircraft simulators "simulate" aircraft handling ?

 

[jb747]

Begs the question, before the days of computer simulations how did aircraft simulators "simulate" aircraft handling ?

There has been a constant progression of simulator fidelity over the years. As computer systems become more powerful, not only have they been able to reproduce effects in the sim, but the analyses that the aircraft handling characteristics have been based on have become more accurate. I'd expect that it's rare for the test pilots to unearth any dramatic handling surprises these days...though I'm sure the occasional sleeper turns up.

Airliners are never tested beyond the limits of control as a military aircraft might be. They aren't designed for the loads that might induce. So, at the extremes, the mathematics of the designers is as far as the testing goes. This does provide a good basis for emulation in software. But, it's worth noting that the flight simulators that airlines use, are not the same sort of simulators that system designers and flight test people use. Flight sims reproduce known handling and behaviour...whilst systems simulators attempt to deduce system behaviour from scratch. The upshot is that if effect X is thought to happen, then that's what will be programmed into the sim. If effect Y is really happens, then the simulation will be wrong. That was the case with the reverse thrust simulation.

I saw an example of this in the early days of the 380. During a flight from Singapore, we lost an air data computer. There are two others, so there was no effect upon the flight. But, about 2 hours later, we lost the probe heat to a side slip vane. That had the effect of rendering a second ADR out of service. The aircraft totally dropped the bundle, and lost all of its automatic functions, and also reverted to alternate law II (which is close enough to direct law). According to the manuals, and the simulator, it should only have gone to alt law I, and the automatics should have remained available. Needless to say, the sim was quickly modded to show the real effects of such a dual failure.