Ask The Pilot

[JohnM]

At the smaller end of the scale (!) where we are making a last minute adjustment for a passenger or two, we simply use 100 kg per passenger. I understand that the actual loading people use weights that might more accurately reflect the nationality of the passengers.

Interesting... .

 

[N860CR]

Ask The Pilot

This might be a really silly question, but here goes: I understand that a pilot is paid by the 'flight hour', have you ever heard of someone making a flight take longer than it should for the extra cash? Or is the difference not enough to make it worth while?

Not all airlines operate like that. I'm not sure what mainline do (JB will correct me), but most Aus carriers pay for the duty your rostered and not any extra (in most circumstances).

So when you're going into BNE and holding over Maleny for 40 mins (for the second or third time that day for the crew) and you land 2 hours late or so, don't think the crews are getting paid any extra! They're paid to complete the duty they were rostered for (regardless of how long that takes).

 

[RooFlyer]

A very valid question...to which the answer is no, we don't do an acceleration check. Probably a number of reasons, not the least of which is that civilian runways don't have distance to run marker boards (though the military do).

Such a check would probably mean that the Singair tail scrape in Auckland, Emirates in Melbourne, and Air Florida in Washington might have been avoided.

It checks against a number of things. Overloading. Incorrect take off calculations. Incorrect power settings. It would need to be calculated for every take off. You don't get a feel for things when the numbers vary as much as they do.

Thanks again. I find it surprising though (but now understand why it's not done). I won't cough about the time it takes for the 'before we close the doors' checks so much now.

Have you ever had the feeling (as I have) as the plane is hurtling down the runway .. "Gee I really would have though we'd have hit rotation by now ...." and then "Ok, rotation any time now would be good ..." - but knowing your actual thoughts would be more sophisticated than that

 

[Sprucegoose]

Ask The Pilot

At the smaller end of the scale (!) where we are making a last minute adjustment for a passenger or two, we simply use 100 kg per passenger. I understand that the actual loading people use weights that might more accurately reflect the nationality of the passengers.

I was weighed years ago checking into a Continental flight to Guam. They were checking their std weights. Airlines should welcome kids!!

 

[serfty]

What are the grooves in the concrete on the runway, at the start point where the plane lines up for take off?

There are groves in the surface about 100mm apart!


Sent from AFF Mobile Edition

They are to drain water way somewhat to reduce the risk of hydroplaning.

They tends to fill with tyre rubber after a while so require regular attention.

There is a member here who posts occasionally who is involved with a business that specialises in the maintenance of those grooves ... he travels SE Asia in doing so.

 

[jb747]

What are the grooves in the concrete on the runway, at the start point where the plane lines up for take off?

There are groves in the surface about 100mm apart!

They normally cover the entire length of the runway. They're there to help drainage, and we're able to consider grooved runways as 'dry' for take off calculations. A number of methods are used to help drainage, some of which are more effective than others. Grooving works pretty well.

If nothing is done to help the drainage, and the rain is heavy enough for us to consider the runway 'contaminated', the performance penalties are so great as to preclude flights like Singapore-London.

 

[jb747]

Thanks again. I find it surprising though (but now understand why it's not done). I won't cough about the time it takes for the 'before we close the doors' checks so much now.

One of the most important lessons that any pilot can learn is to NEVER do anything until he is ready for it. Little external forces that push you along (such as the countdown clocks at the Virgin gates) provide subtle pressure to shortcut and hurry. A small error in the numbers (i.e. Emirates in Melbourne) can have a disastrous outcome. There's any number of ways to get things wrong, so I go when I'm ready...not when somebody on the ground thinks I should go.

Have you ever had the feeling (as I have) as the plane is hurtling down the runway .. "Gee I really would have though we'd have hit rotation by now ...." and then "Ok, rotation any time now would be good ..." - but knowing your actual thoughts would be more sophisticated than that

No, thankfully. My response wouldn't be to wonder though. Prior to V1 I'd abort, and after, I'd slam the levers to TOGA. Much better safe than sorry.

 

[jb747]

This might be a really silly question, but here goes: I understand that a pilot is paid by the 'flight hour', have you ever heard of someone making a flight take longer than it should for the extra cash? Or is the difference not enough to make it worth while?

Like everything, there are different methods used by different airlines, and sometimes within the same airline.

Within Australia, payment by the actual flight hour was one of the things forced into being by the '89 dispute. That opened up so many cans of worms that it was ultimately abandoned in favour of pre-calculated hours values (which strangely tended to be shorter flight times than the aircraft were capable of...). Some variation of that is still in use domestically.

QF long haul were not involved in '89 (thankfully), and so use a number of different calculations for pay. Basically, a single day, in isolation, will attract a fixed amount of pay as a minimum. You won't be paid any extra for either flight or duty time increases (or decreases). Once the duty exceeds 12 hours or so, there are extra 'overtime' payments. These could be manipulated, but doing so would be so unprofessional, that I'd be happy to see anyone doing so removed. I'd expect it would tend to stand out on any graphs of sector time.

Whilst a 'management' solution might be to do away with such payments, that too would likely have a downside. For instance, a crew that diverts, or is delayed, and ends up in the CASA discretionary time area (i.e. crew choice whether to extend or not) might consider things differently if they were not being paid.

 

[Walter_Plinge]

Apologies if this has been covered previously.

Talking about fuel weight makes me wonder about how the weight of passengers is calculated or allowed for? Checked baggage is presumably simple as each piece goes over the scales and presumably that is electronically integrated into the flight information.

But what about the seemingly ever-increasing unit-size mass of flesh? 400 pax x 75 kg is 30 tonnes :shock:.

Air Midwest Flight 5481. 21 fatalities. Poor maintenance combined with overloaded aircraft and centre of gravity too far too the rear.

"As a result of the weight issues discovered the FAA planned to investigate and potentially revise estimated weight values, something that had not been done since 1936. Air Midwest used an average weight of 200 pounds (90.7 kg) per passenger after the accident, but the NTSB suggests that airlines use actual weights instead of average. 70% of small air carriers still use average."

 

[jb747]

Air Midwest Flight 5481. 21 fatalities. Poor maintenance combined with overloaded aircraft and centre of gravity too far too the rear.

As usual not one single cause, but the holes lined up.

"As a result of the weight issues discovered the FAA planned to investigate and potentially revise estimated weight values, something that had not been done since 1936. Air Midwest used an average weight of 200 pounds (90.7 kg) per passenger after the accident, but the NTSB suggests that airlines use actual weights instead of average. 70% of small air carriers still use average."

You really need to read the full report, and not just a Wikipedia version of it.

http://www.ntsb.gov/doclib/reports/2004/AAR0401.pdf

Whilst the passenger standard weights were light, the overwhelming cause of the accident was the extremely reduced elevator authority. Worth noting that in the similar events listed, it shows one aircraft that completed most of its flight with the CofG around the 45% area..though they did ultimately lose control.

The Concorde that crashed was also apparently operating with a CofG aft of the aft limit. Having the CofG towards the rear will reduce the aircraft's pitch stability, but will also reduce what is known as 'trim drag', so it can be a fuel saver. The 380 operates with the CofG around 42% for most of a flight, and takes off at 39.5%...though an FBW aircraft can handle reduced pitch stability.

For those who don't realise, the tail of an aircraft actually produces NEGATIVE lift. Its lift vector is pushing downwards. That's needed to make the aircraft controllable, but it's also effectively 'weight' that extra lift must be produced to 'carry'. Canard designs (like the Viggen) produce positive lift...but apart from one Rutan design that doesn't seem to have made it into the civilian passenger carrying arena. You can also make a canard aircraft effectively unstallable, by ensuring that the canard stalls before the wing...which will give a pitch down and subsequent reduction in angle of attack.

 

[The Rok]

Ask The Pilot

Jb, any idea of your movements over the next few days? I'm off to LHR on Monday!

 

[jb747]

Jb, any idea of your movements over the next few days? I'm off to LHR on Monday!

In the sim on Monday...

 

[Mogul]

JB,

Was just watching something on Antartica and was wondering what mods if any are done to the aircraft that fly there.

I recall you saying that reverse thrust doesn't really do anything to help slow the aircraft down, do these aircraft have studded tyres to help with traction or is it just a very long runway.

 

[jb747]

Was just watching something on Antartica and was wondering what mods if any are done to the aircraft that fly there.

I recall you saying that reverse thrust doesn't really do anything to help slow the aircraft down, do these aircraft have studded tyres to help with traction or is it just a very long runway.

Reverse is better than nothing...it just doesn't do as much as people think. Beyond that, I have no idea what they'd do to set up aircraft to operate down there.

 

[chrisb]

Ask The Pilot

JB, tonight on qf71 (a330) an announcement was made during taxi that interference had been detected and people should check their phones are off. Have you ever heard of an announcement like that being made? What would trigger it?

Thanks.

 

[jb747]

JB, tonight on qf71 (a330) an announcement was made during taxi that interference had been detected and people should check their phones are off. Have you ever heard of an announcement like that being made? What would trigger it?

There is no system to be triggered. Most likely someone heard a phone ringing.

 

[mjt57]

Reverse is better than nothing...it just doesn't do as much as people think.

Yeah, but it sounds cool...

 

[richie9x]

I understand that both the 747 and A380 have a rudder split into two sections that can move independently, while smaller jets (e.g. 767, 737) normally have a single section rudder. From what I have noticed sometimes both sections move in unison, while other times they will move differently. Does the pilot have direct control over each section of the rudder? Or does the plane just take the input from the rudder pedals (and control column as well?) and the systems move the rudder sections as needed?

On a flight this year on an A330 it was a bit windy at departure, so windy there was talk of ramp operations being suspended The plane pushed back from the gate but just stayed there and did not taxi. The pilot came on and said that because it was so windy if they taxied while waiting in queue exhaust would be blown into the air con. So the plane just waited back from the gate then eventually taxied straight onto the runway. I can't recall having done that before. Would there also be an issue with exhaust getting blown into the engine intake and cause an engine stall? I assume this would also need cooperation from the tower. Is it something that a pilot could request?

From what I understand QF32 made a pan-pan call, while QF30 was a mayday call. With mayday being the more high priority of the two. Is there much difference in the response given by ATC and responders for the two different calls?

 

[jb747]

I understand that both the 747 and A380 have a rudder split into two sections that can move independently, while smaller jets (e.g. 767, 737) normally have a single section rudder. From what I have noticed sometimes both sections move in unison, while other times they will move differently. Does the pilot have direct control over each section of the rudder? Or does the plane just take the input from the rudder pedals (and control column as well?) and the systems move the rudder sections as needed?

Basically the rudders both move as commanded by the rudder pedals. The hydraulics/electrics to them are split up in such a way that you should always have some level of rudder control. As you can imagine, application of large amounts of rudder applies a lot of force to the tail plane, especially the upper rudder section, so the aircraft all have some way of limiting inputs, depending upon speed. The lower section only is additionally used by the automatic systems as a yaw damper.

On a flight this year on an A330 it was a bit windy at departure, so windy there was talk of ramp operations being suspended The plane pushed back from the gate but just stayed there and did not taxi. The pilot came on and said that because it was so windy if they taxied while waiting in queue exhaust would be blown into the air con. So the plane just waited back from the gate then eventually taxied straight onto the runway. I can't recall having done that before. Would there also be an issue with exhaust getting blown into the engine intake and cause an engine stall? I assume this would also need cooperation from the tower. Is it something that a pilot could request?

Ramp operations can be suspended for a number of reasons; thunderstorms being the one you're most likely to see. In that event, if you're still at the gate, you're now trapped until the suspension is lifted. So, the best solution will be to get off the gate, and to get the aircraft running on it's own power, so that you can go as soon as the conditions allow. Not sure about the exhaust...that's always an issue if you get a bit close to the aircraft in front, and is alleviated by simply sitting back a bit. It won't cause any issues with the engines, but it certainly becomes very unpleasant if it gets into the cabin. Tower aren't an issue.....just tell them what you want, and they'll accommodate it if they can.

From what I understand QF32 made a pan-pan call, while QF30 was a mayday call. With mayday being the more high priority of the two. Is there much difference in the response given by ATC and responders for the two different calls?

Some parts of the world (notably the USA) don't even know what a PAN is. There you have an emergency, or not. Many places seem to react the same way no matter what you say to them...which has the bad outcome of making pilots reluctant to say anything (for instance telling one ATC agency that I had a deflated tyre, wanted NO assistance, but wanted them to inspect THEIR runway after landing, resulted in them calling everyone out).

PAN and MAYDAY differ in degree. There is no hard and fast rule, but like most things, you'll know it when you see it.

 

[markis10]

From what I understand QF32 made a pan-pan call, while QF30 was a mayday call. With mayday being the more high priority of the two. Is there much difference in the response given by ATC and responders for the two different calls?

There is a bit if difference from an ATC perspective depending on where the call is, if its in the circuit area a Mayday will invoke immediate activation of the crash alarm which rolls out emergency services and alerts nearby facilities of the situation (Police/Hospital etc) while a PAN will often just result in activation of on field services. Enroute there is not much difference, other than priority for landing where a pan aircraft will not jump a queue ahead of a med aircraft in most circumstances.