Ask The Pilot

[mjt57]

Trouble was that it was nowhere near stalling, and the system response of nose down pitch, which CANNOT be overridden on the joystick, was exactly the wrong outcome. Thankfully there were some actual pilots on board, who not only quickly decided they wanted to get rid of this 'safety' system, but also came up with a way of doing so.

What did the guys to to bypass this protection scheme?

Some time back you gave us a brief explanation of how the various "laws" relating to aircraft control work. I think that I recall that one of them was a purely manual system. Would the pilots have selected that mode?

 

[jb747]

What did the guys to to bypass this protection scheme?

Some time back you gave us a brief explanation of how the various "laws" relating to aircraft control work. I think that I recall that one of them was a purely manual system. Would the pilots have selected that mode?

You can't select any of the modes. That, in my opinion, is a huge weakness. But, you can fail a couple of other systems, and force a reversion. So a couple of ADRs off, or all three PRIMs, and you'll get a reversion to a mode that should let you fly. But, it isn't one switch, and they are hidden away on the overhead panel. Falls into the category of "it will not happen".

 

[por930]

You can't select any of the modes. That, in my opinion, is a huge weakness. But, you can fail a couple of other systems, and force a reversion. So a couple of ADRs off, or all three PRIMs, and you'll get a reversion to a mode that should let you fly. But, it isn't one switch, and they are hidden away on the overhead panel. Falls into the category of "it will not happen".

HI JB,

So do airlines such as QF have Standard Operating Procedures for their FBW aircraft to cater for such 'rare' occurrences? or is it left to the ingenuity of the air crews experience to work out what to shut off to achieve a "I can sort of control this thing" law. I am sure you know only too well that while the 'experts' have thought out these laws and the aircraft's responce for 'any" given situation, some times the situations gets mixed together and the FBW outcome is not has desired by the aircrew. I think in a tropical storm with the aircraft being violently thrown about, I would rather have an experienced captain with several thousand hours flight hours in control.....than a computer deciding on what input to use. And yes I agree, the days of non pilot passenger aircraft are a long way off, if ever.

 

[jb747]

So do airlines such as QF have Standard Operating Procedures for their FBW aircraft to cater for such 'rare' occurrences? or is it left to the ingenuity of the air crews experience to work out what to shut off to achieve a "I can sort of control this thing" law.

QF, and I expect most airlines, don't invent too many extra procedures...and pretty well everything has to be approved by the makers anyway.

But, you do get shown lots of interesting things in both the conversion, and recurrent, sim sessions.

 

[Ansett]

QF, and I expect most airlines, don't invent too many extra procedures...and pretty well everything has to be approved by the makers anyway.

But, you do get shown lots of interesting things in both the conversion, and recurrent, sim sessions.

I guess JB at the end of the day it comes dow to a level of competence of the pilot combined with the standards of the airline and the training regime combined with the general experience of the pilot ( ie non commercial experience) Based on my observations QF may well be light years ahead of competitors and I for one hope that this never changes.

 

[drpurpleturtle]

How hard would it be to land a 747 with a missing landing gear JB?

Incident: Virgin Atlantic B744 at London on Dec 29th 2014, hydraulic problem, landed safely without right main gear

[video=youtube;zLpRu1EzyGE]https://www.youtube.com/watch?v=zLpRu1EzyGE[/video]

 

[jb747]

How hard would it be to land a 747 with a missing landing gear JB?

Incident: Virgin Atlantic B744 at London on Dec 29th 2014, hydraulic problem, landed safely without right main gear

As you can see, the aircraft is stable, just wing down in that configuration. It might have been better if he'd had more flare, though video is always deceptive....and it's always much easier from the computer than it is in the coughpit.

Items from the QRH:
If any wing or body gear is notextended, deployment of the thrustreversers may affect directionalcontrol.

If the nose gear is not extended, donot deploy the thrust reversers untilthe nose contacts the runway.

Delay extending the speed brakes untilthe nose and both sides of the aircrafthave touched down.

If any wing gear is not extended, useaileron control to keep the wings levelduring the rollout until the aircraftcomes to a complete stop.

If any wing or body gear is notextended, do not attempt to taxi theaircraft or use the tiller. Brakingeffectiveness is reduced.

If both body gear are not extended,the aircraft may tip tail down on theground. Door 1 escape slides are thenunuseable.

Landing Checklist
Speedbrake ......................... DN
Landing gear ...................... DOWN
Flaps . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ___

The landing is done normally, but the spoilers are left disarmed, until after the gear is on the ground. In this case, they don't seem to have been raised at any point. Reverse is also held for quite a while, which would be a discussion point given the proximity of two of the engines to the ground.

PS...Now that I've seen a few more videos, it would seem that he initially had nose and body gear down, with both wing gear retracted. The gear doors are open for the landing, which is indicative of an alternate lowering of the body gear. Basically, the doors are opened, and the gear falls down under its own weight. So, my guess would be that he's lost one of the hydraulic systems. The might also explain the limited flare and spoilers.

 

[clazman]

JB, they seems to have taken a while to get the PAX of the aircraft and EMS to approach the aircraft?

 

[jb747]

They seems to have taken a while to get the PAX of the aircraft and EMS to approach the aircraft?

Can't approach too closely until the engines are shut down...and unless there was an indication of fire, there's no reason to anyway. They were close enough.

Same with passengers. They're better off in their seats until buses are ready to take them to the terminal. There is no need to rush off the aircraft...and, they would be in the way on the tarmac anyway. It's a time to hasten slowly.

 

[QFflyermelbourne]

Happy new year JB.

I have two areas of interest for this post...

1.) Do you have your latest roster through the end of Jan/Feb?

2.) And on another topic, given all you have said with your criticisms of the way the Airbus systems are designed, would it be your view that the Boeing design is better? Is one potentially even safer than the other? And to create a hypothetical, if Boeing were building something the same size as the 380 and QF had purchased them and pay grade and prestige of rank didn't come into it, which would you prefer to be on?

All the best for a happy and safe 2015 in the skies...

 

[jb747]

I have two areas of interest for this post...

1.) Do you have your latest roster through the end of Jan/Feb?

This is normally the week for the roster runs, but I expect things will be a bit slower than usual at this time of year. It should be out early next week.

2.) And on another topic, given all you have said with your criticisms of the way the Airbus systems are designed, would it be your view that the Boeing design is better? Is one potentially even safer than the other? And to create a hypothetical, if Boeing were building something the same size as the 380 and QF had purchased them and pay grade and prestige of rank didn't come into it, which would you prefer to be on?

A somewhat loaded question. The reality is that both have their positive and negative aspects. Much of the Airbus design is excellent, and I'd go so far as to suggest that the A320 and A350 could have the edge on their competition. The 747-8 and 380 were never really equals. The 777 in its early incarnations was also less than wonderful, though the later versions seem to be excellent.

The weakness that I find in the Airbus is all based around the man/machine interface. Ergonomics. They all have their traps though, as Turkish at AMS, and Aseana at SFO have shown us.

Is one safer than the other? Not really. I think FBW is inherently safer than non FBW, but it could be better if the interface were designed by engineers for the pilots, as opposed to being designed for themselves. They aren't the end users, but sometimes seem to forget that.

 

[warpspeed]

I think FBW is inherently safer than non FBW, but it could be better if the interface were designed by engineers for the pilots, as opposed to being designed for themselves. They aren't the end users, but sometimes seem to forget that.

Are there any feedback mechanisms in place for aspects like this to be fed back to the manufacturer for future improvement or service updates? and if so, do they listen much? I find it's something that sadly lacks in many industries. As a 'customer experience' person it drives me crazy when I see things that have been designed and implemented with little or no regard for usability by the end user.

 

[jb747]

do they listen much?

What do you think? They will do anything you want, as long as it does not involve changing anything.

 

[por930]

What do you think? They will do anything you want, as long as it does not involve changing anything.

JB, It is a sad indictment against the designers. You guys don't drive buses or trains which can be involved in some scary moments no doubt, but at least the drivers can eventually stop and assess the situation, and even get external assistance. You guys are several thousand feet in the air, in a very 3 dimensional environment, moving very quickly, having to both control the a/c and think of a situation where you can get the a/c on the ground with the least possible loss of life and damage to the a/c. While all this is going on, you would hope the a/c was also in your camp as well.

Happy New year JB, may you have many more.

 

[Boris spatsky]

Changing things is not necessarily a simple process due to certification requirements. Western aircraft are certified against stringent airworthiness design standards - change means $$ and engineering effort. Even minor software changes can require significant engineering effort. Which means the manufacturer charges the user. A lot of the time it is easier to put up with something annoying than pay to change it.

 

[jb747]

This was posted in another thread, but it makes interesting reading. I think the translation is most likely not all that accurate, but it certainly touches on many of the hardware factors that we've been talking about.

Should Airplanes Be Flying Themselves? | Vanity Fair

 

[flychrisfly]

Hi Pilot Peeps

how does a pilot know the bank angle to use when making a turn so that the passengers (and pilots) don't slide sideways in their seats? Or is it one of those naturally self-resolving functions that the bank angle required for the turn results in the net force vectors being directed "down" or parallel to our spines?

Thanks!

 

[jb747]

how does a pilot know the bank angle to use when making a turn so that the passengers (and pilots) don't slide sideways in their seats? Or is it one of those naturally self-resolving functions that the bank angle required for the turn results in the net force vectors being directed "down" or parallel to our spines?

In a balanced turn (which should be all of them), that's exactly the case. The overall 'g' vector remains perpendicular to the floor.

Assuming level, 1 g flight....as you roll into a turn, the overall amount of lift being made stays the same. But, it is no longer vertical to the ground, so, you can resolve that into two vectors, one perpendicular to the ground, and one towards the centre of the turn. The one towards the centre is what makes the turn happen...but, the component that is vertical is no longer generating sufficient lift for us to maintain level...so we'll need a bit more backstick to get a slightly greater angle of attack to make that part of our vectors equal to 1g again. In level turns, the component of lift that is in the vertical must always equal 1g.

If someone talks about a 2g level turn, it means that they have sufficient bank applied for a total of 2g to be needed, but to make that 1g of vertical (60º BTW). As the bank increases, we'll eventually get to a point at which you can no longer make that important vertical component. At around 84º of bank you'll hit the 'g' limit for things like the F16...so a level turn beyond that is basically impossible.

A bit more discussion of vectors, and why they are important, here http://www.avweb.com/news/airman/190089-1.html

 

[jukebox333]

JB, I was watching the procession of take-offs whilst waiting at SYD for my flight on New Year's Day.

The departures were all to the North, across the inner west and then turning as required.

What I did notice was how much flatter the QF A380 take off's were compared to say a CX B777. From my seat, even early in the climb it was obvious the bigger aircraft were in no hurry to gain altitude.

Is that an aircraft type specific thing, an ATC factored thing, or a destination/fuel load governed thing? (or none of the above?)

 

[Craigie]

This was posted in another thread, but it makes interesting reading. I think the translation is most likely not all that accurate, but it certainly touches on many of the hardware factors that we've been talking about.

Should Airplanes Be Flying Themselves? | Vanity Fair

Wow, fascinating reading.

I'd like your opinion on a few points in that article but perhaps would be much easier to ask in person than type it.. So I'll hold back a bit.

Simple, possibly stupid question but need to ask. When the captain entered the coughpit having not been aware of the indications failing prior to his entry, wouldn't he have seen a massive nose up attitude on the PFD(?), a large rate of descent and stall warnings? Leading to a clear stall indication?? You cannot speak for the man but can you perhaps speculate on his apparent confusion at what I'd (very laymans) consider to be an obvious situation?

Why do you suppose Bonin continued with his inputs on his stick after Roberts clearly said "I have control"? His dialogue indicated that due to his lack of understanding about what was happening that he was looking to Roberts (perhaps because of his seniority status) as someone who could help/fix the situation. But when Roberts intervened with the correct input, Bonin simply reversed that input without a word??

Should there perhaps be some kind of system where pilots are required to fly in conventional aircraft that aren't so automated for a period of time (say x thousand hours) before allowing them into such automated setups to allow them to understand aviation first and machines second? Of course I have no idea how this would be implemented in the real world.

As always, thanks.