Ask The Pilot

[jb747]

Speaking of wind ... I was on a Melbourne to Sydney flight on Thursday and we were initially told that we would be using the E/W runway due to high winds. But as we started our approach the captain said that conditions had eased on we would be using the third runway as normal.

What aircraft type?

It was not a normal landing!

Perhaps, but as I think I've said before, perceptions from the cabin and from the coughpit can vary pretty dramatically. I recall a woman in Brisbane who had a go at me over my 'poor' landing. Given that it was in a 38 knot crosswind, and was exactly on the targeted aim point I was actually quite happy with it. I asked how her last landing was, but didn't get a reply.....

A fair bit of buffeting and throttle work was to be expected and we passed over the threshold a little higher and faster than usual (IMHO) but nothing concerning to me at the time.

I can't judge the speed and height from the cabin.....

The final 10-15 seconds getting the aircraft on the deck was the sphincter clenching bit. In particular the left wing dipped sharply downwards to the point where I thought the tip would touchdown before the landing gear.

At a guess, the cross wind was from the left. Take the drift out, and drop the upwind wing slightly. Depending upon the aircraft type, that can be quite a few degrees. That will cancel out much of the downwind travel that starts as soon as you remove the drift. In some aircraft you can allow the aircraft to land like that. In the Boeings you can land with the drift intact, and you sort out where the aircraft is pointed after touchdown. That results in some very large rudder inputs, and isn't all that comfortable, but the aircraft track remains straight down the runway. A combination of the two is common.

The plane then righted itself and we got the left and then right wheels on the deck, and then there were some pretty extreme rudder inputs as if we were driving through a chicane.

The aircraft didn't right itself.

Rudder inputs as you describe can be quite normal. In a limiting crosswind landing you are moving sideways at about 80 km/hour...think about that in your car. Controlling that sort of motion does not respond to gentle inputs.

So the question I have is ..... is there a point at which aborting a cross-wind landing is as dangerous as persevering?

You can discontinue any landing up to the point that reverse thrust is selected.

 

[Julesmac]

JB, we travelled overseas last year on SQ A380. I have to say (maybe it was cos we were cocooned in business with plenty of bubbles...) it was the smoothest thing I have ever experienced for takeoffs and landings. What's your opinion? And would you like to fly the Dreamliner? I'm not sure who makes it, showing my ignorance, but how do you imagine that would differ from the A380?

 

[jb747]

JB, we travelled overseas last year on SQ A380. I have to say (maybe it was cos we were cocooned in business with plenty of bubbles...) it was the smoothest thing I have ever experienced for takeoffs and landings. What's your opinion? And would you like to fly the Dreamliner? I'm not sure who makes it, showing my ignorance, but how do you imagine that would differ from the A380?

Smooth takeoffs are easy in the 380. It weighs a million tonnes, and you use the minimum thrust necessary..... Landings are also normally reasonably smooth. I won't claim better than that, because someone will hold me to it.

The Dreamliner. What a great marketing name. Call it the 767+, or the 777-. Not good marketing, but about as accurate.

I have no interest in flying it. It isn't some great leap into the future as far as I can tell. It's simply an aircraft built with new materials, and FBW. Boeing know how to do FBW, and we'll all wait to see if they know how to do new materials.

How will it differ from the A380? In about every way you can imagine. Firstly, it is not a big aircraft. It is roughly 330-200 size. It's all about point to point, whereas the 380 is about hubbing. It's more likely to make money for Boeing than the 380 is for Airbus. Will it offer some great new experience in the sky....I very much doubt it.

 

[Awesom Andy]

Call it the 767+

If it is indeed a 767+, it would be an excellent aircraft.

 

[Sprucegoose]

If it is indeed a 767+, it would be an excellent aircraft.

Or for that matter a -777. Both are two of my favourite aircraft.

Its advantage is economic. I read an interesting article on GE and how they keep updating the engine performance.

I am sure there would have been big leaps in maintenance as well. These days it's about the accountants perspective (sadly)

 

[erkpod]

Yesterday I did my first sim ride on an A320 sim at Bankstown airport. Certainly a totally different type of flying altogether compared to the couple of hours I've had in the B737 sim at Darling Harbour.

One thing I noticed with the Airbus controls compared to the Boeing controls was the lack of feel with the former when it came to things like selecting flaps settings & the like. Also finding the centre position for the joystick when leveling the wings.

As a newbie it felt like I had a better feel with the yoke on the 737.

I did a circuit of Sydney & a circuit at SFO including flying under the Golden Gate Bridge. I know then (and also on my train sim), it felt very strange to do the "wrong" thing even though I know I'm in a sim & have an instructor with me.

Much respect from me to all the pilots out there!

 

[bryanjones]

Like so many things in aviation, there is no one answer to your question. The fuel flow figures will vary dramatically with temperature, altitude and weight.

In the case of cruise, starting at max weight, the flow will be in the order of 4,000 kgs per engine, per hour. That will reduce to about 2,800 kgs/hr by top of descent.

Climbing, the fuel flow will progressively reduce. It will start at about 8,000 kg/hr (per engine), and end at very slightly above the cruise figure (say about 4,200 kgs/hr).

Idle...about 400 kgs/hr up high, down to about 800 kgs/hr.

So on say a 14 hour flight across to DXB you would use 4 x 3500 x 14 kgs of fuel? Guessing this is approx 250k worth. So when an incident happens and you have to dump, does the airline suck it up or are their insurances for this kind of thing?

 

[mindthegap2154]

So on say a 14 hour flight across to DXB you would use 4 x 3500 x 14 kgs of fuel? Guessing this is approx 250k worth. So when an incident happens and you have to dump, does the airline suck it up or are their insurances for this kind of thing?

I would suggest that there is currently a UA Captain sitting at the Stamford at Mascot who is pondering the same thing

 

[CaviAck]

I would suggest that there is currently a UA Captain sitting at the Stamford at Mascot who is pondering the same thing

In the name of science and attaining information, I suggest we go knock on some doors

Don't shoot I'm just kidding!

 

[petercr]

@ mindthegap - plus the cost of a new tyre (about $5-10k plus tyre disposal levy ) plus any other possible damage and then the costs of hotelling passengers and crew for 24hrs as the flight was canx (and not just re-timed). That would be one heck of an excess if it was insurance...

JB, in circumstances like this would this they get another plane to do a quick check of any potential damage and then give a go/no-go?

EDIT: it appears it was two (!?!?) burst tyres on the same truck... (so double the tyre costs above)

 

[jb747]

Yesterday I did my first sim ride on an A320 sim at Bankstown airport. Certainly a totally different type of flying altogether compared to the couple of hours I've had in the B737 sim at Darling Harbour.

One could suggest that neither are actually flying.

One thing I noticed with the Airbus controls compared to the Boeing controls was the lack of feel with the former when it came to things like selecting flaps settings & the like. Also finding the centre position for the joystick when leveling the wings.

As a newbie it felt like I had a better feel with the yoke on the 737.

Basically there is no feedback with the Airbus joystick system. Wings level...just get it close and let go of the stick. Even when manually flying, we actually 'let go' of the stick for a substantial percentage of the time.

All of the controls are simply switches. They may look like the analogue controls of old, but that is the limit of the relationship. Feel would mean nothing.

 

[Major]

What could cause tyres to blow on takeoff, apart from FOD ?

 

[jb747]

So on say a 14 hour flight across to DXB you would use 4 x 3500 x 14 kgs of fuel? Guessing this is approx 250k worth. So when an incident happens and you have to dump, does the airline suck it up or are their insurances for this kind of thing?

Fuel dumping is a quite rare event. I've only done it once in almost 30 years of airline flying. If you have to, then it's simply an operational cost.

You don't necessarily dump it all either. In a 747 you can pretty well jettison it all if you want, but in most cases of dumping you'd simply jettison until you reached a reasonable landing weight. Dumping as much as you can is a rare subset of the entire experience.

Airbus treat it differently, and I probably don't agree with their thinking on this. They allow (in the 380) the fuel from all but the main tanks to be dumped. That has the effect of leaving you with about 80 tonnes of fuel, and so still about 60 tonnes above 'max' landing weight. That then brings us back to their definition of 'max'...and the reality is that you can land at well above that in certain circumstances. All well and good if the jettison is to allow a healthy aircraft to land with a sick passenger. On the other hand, an overweight landing with a brake or flap (or both) problem is more of an issue, and would be a good time to get rid of all the fuel you can.

On QF30 we dumped all the fuel we could in the time available. That put us about 30 tonnes below max landing, and left us with about 30 tonnes remaining. QF32 was unable to dump at all, because the fuel system detected some issues, and as a result inhibited all fuel jettison.

 

[jb747]

I would suggest that there is currently a UA Captain sitting at the Stamford at Mascot who is pondering the same thing

I doubt that he's pondering anything of the sort. Sounds to me that he did a nice job.

 

[jb747]

What could cause tyres to blow on takeoff, apart from FOD ?

FOD would be my first guess. A brake issue is possible, but should really only affect one wheel. There are scenarios though in which the brakes could be in alternate modes in which they are treated as a pair.

 

[mindthegap2154]

I doubt that he's pondering anything of the sort. Sounds to me that he did a nice job.

Of course that was intended tongue in cheek. Your totally right anyone that can an aircraft on the ground with any type of emergency situation is a genius in my book. Shows that you should always be paying attention on take off and landing.

 

[mjt57]

JB, I assume that you've heard all the usual aviation jokes and stories perpetuated as real or as myths or whatever (such as the Qantas maintenance defects reports which started life as a USAF or US Navy one). But there was also some stories going around in aus.aviation. One related to an SR71 "cruising" at 80,000ft or thereabouts. It requested clearance to 60,000ft which LA Center responded, "if you can get to 60,000ft, then go for it". The wry reply, "roger, DESCENDING to 60,000ft".

Now, if that aircraft was in ATC controlled airspace, then wouldn't it have a transponder operating and a squawk code assigned? If so, surely the controller would've had all of the aircraft's data on his display.

Speaking of transponders, the info that we see on Flight Radar is generated from them, right? If so, is the aircraft's speed coming from that, or does ATC's equipment measure it independantly?

 

[markis10]

JB, I assume that you've heard all the usual aviation jokes and stories perpetuated as real or as myths or whatever (such as the Qantas maintenance defects reports which started life as a USAF or US Navy one). But there was also some stories going around in aus.aviation. One related to an SR71 "cruising" at 80,000ft or thereabouts. It requested clearance to 60,000ft which LA Center responded, "if you can get to 60,000ft, then go for it". The wry reply, "roger, DESCENDING to 60,000ft".

Now, if that aircraft was in ATC controlled airspace, then wouldn't it have a transponder operating and a squawk code assigned? If so, surely the controller would've had all of the aircraft's data on his display.

Speaking of transponders, the info that we see on Flight Radar is generated from them, right? If so, is the aircraft's speed coming from that, or does ATC's equipment measure it independantly?

It's more than likely it was outside controlled airspace and "dark", strangely enough military flights often don't advertise their presence outside of controlled airspace, especially not above it when the only other traffic will be military or space bound. Controlled airspace tops out at FL450 in most places on the basis anything higher is unusable by most civil traffic.

Aircraft speed data is originated in the aircraft. On the old bright displays I used we could estimate the speed by the distance between paints, depend on which radar range you were using M.80 was about 50mm, while the Concorde painted closer to 2-3cm.

 

[workingman]

JB,

I just have to add my thanks to a great thread. I only discovered this 3-4 weeks ago and I have spent far too much time over that period reading all 488 pages. I have certainly learnt a lot, and had a lot of misconceptions removed from my thoughts.

I have not flown for years, well since I was the in the air cadets back in the UK too many years ago. First planes were the old Chipmunk trainers. Interestingly cadets sat in the rear seat, whilst for a real pilot training they would be in the front seat with the instructor in the rear seat. As it was extremely rare for a cadet to be allowed to land a Chipmunk then that probably explains why. Experiencing my first loop the loop and barrel roll is an experience I will never forget, nor flying over the old QEII as she approached Southampton docks. I did get one flight in a Bulldog, which was then the current trainer for the RAF, which was great as I was sat next to the pilot, not hidden in the back.

My greatest experience though was at a summer camp at RAF Leeming. 2 cadet names were picked out of a hat, and then my name picked as 1 of 2 reserves. Well one cadet bottled out of the flight and I replaced him. This was to have a trip in a Jet Provost. 1 hour of total exhilaration. In that 1 hour we covered a huge area of north England and part of Scotland. Seeing what was then the new oil rigs in the North Sea was stunning, and we did a relatively low fly past of a group of them. Of course in those days we did not have cameras every where so I have no visual reminders of those days. To this day I remember the extreme moves, well they seemed it to me, that a military plane does. None of these controlled climbs, banks, and descents that commercial aircraft do.

I followed a link today about the U2 spy plane, Breathtaking spy plane footage. [VIDEO] and the landing at approx. 8 minutes is interesting as it lands on the rear wheel. Reading up on the plane and it seems it has so much lift that landing is extremely difficult and the rear wheel is the easiest way to do it. The chase car you see is actually to give guidance to the pilot and contains another U2 pilot to guide on take off and landing. You mentioned in a couple of your posts that the A380 has a huge amount of lift especially when it is empty for your maintenance flights that the lift makes landings 'interesting'.

Thanks again for the amount of time you spend answering so many questions.

 

[jb747]

Funnily enough I was part of a team that won an air race...and the prize was a Chipmunk. Southern Cross Air Race from 1984. Three teams tied at the end, a civvy from the Moorabbin aero club, the Army with a Kiowa, and the RAAF with a CT4. I was half of the RAAF team, even though I had a black uniform.

Landing very light aircraft can be interesting, but I suspect that the U2 is an entire order of magnitude more difficult. Makes me wonder what it would be like in gusty conditions...impossible comes to mind.

As to your Provost ride...it was all controlled...just controlled to a different plan than seen in the civil aviation world. Huge fun.