Ask The Pilot

[jb747]

I recently flew in an an A330 MEL-SYD. Just before take-off the captain came over the PA to advise that the FO would be 'taking us to SYD'.

Are there any parts of a flight that the captain must carry out, or could she leave the whole thing to the FO and just observe?

Basically the Captain is in charge of the whole flight, but as much as we can, we fly alternate sectors with the FOs. On their sector they do everything as if they were the captain, until the boss feels the need to intervene. Sometimes that means they do all the PAs, sometimes not.

The FOs don't handle any abnormal landings, nor low vis weather.

 

[andmiz]

CG Question
CG implies balance in the fore-aft

As an aircraft travels in an air mass, would not such a balanced aircraft tend to change pitch, oscillate or at least be unstable in pitch?

It depends entirely on the aircraft, but certainly for airliners (and less so for fighters), regulations call for and they're designed to hold positive static and dynamic stability characteristics. Longitudinal static stability is what you're referencing and you'll find more than what you're after at https://en.wikipedia.org/wiki/Longitudinal_static_stability. There's also a friendly explanation with pictures at The 3 Types Of Static And Dynamic Aircraft Stability | Boldmethod

CG Tidbit: Aircraft are more fuel efficient with an aft CG as less downforce required by the tailplane means less drag, but this shorter moment arm also reduces stability (but designed out of the equation). Aircraft like the A330 will transfer fuel from its wing tanks to a tail(trim) tank in-flight and hold the CG within roughly 2.5% of the aft limit as the aircraft burns its cruise fuel.

 

[jb747]

This is something that every pilot will identify with....the rising or setting sun burning your eyeballs out.

 

[jb747]

A couple of pages ago, when I put up the image of the ND, I commented that it has many modes. Over the next couple of posts, I'll put up images of many of them.



And a different range scale...

 

[jb747]

Plan mode.

 

[jb747]

 

[jb747]

Plan mode with the STAR and approach.

 

[jb747]

Nav mode with the radar showing extensive returns...



And a much more common paint...

 

[jb747]

Last one...this is terrain mode, showing Noumea.

 

[Quickstatus]

20kts below max. Close to coffin corner?.

Is there a mountain to the left of the aircraft?.

 

[mjt57]

Interesting screen shots. How did you grab them?

Also, with the line that I guess is your track, vector or whatever you call it, why are so many of them off at an angle to the direction of the "plane" symbol?

 

[jb747]

20kts below max. Close to coffin corner?.

Coffin corner...mention of it normally brings a bit a smile. A widely misunderstood term. There is a description here: https://en.wikipedia.org/wiki/Coffin_corner_(aerodynamics)

Basically though, at the real coffin corner, the stall speed and the maximum speed are equal. You cannot go faster or slower.

I haven't put up any pictures of the displays at lower speeds, because I'm normally a bit too busy then to be taking pictures, but there's a second set of bricks that come in from the bottom of the display. They show the low speed limits (lowest selectable speed and stall speed). If you climb at a constant mach number, the IAS will slowly reduce. Eventually the display will have room to show both the upper and lower limits...and eventually, if you could actually keep going up long enough, they'd meet. In reality, you'd need to be a U2 pilot for it to be an issue. Airliners have nowhere near enough power to get high enough.

A real issue appears if you slow down at altitude. The green donut on the display is Vmin drag. You NEVER slow below that speed at altitude (and it's a dumb idea down low too). Once below the green dot, you may not have enough power to accelerate again, and would have to trade height for speed.

Is there a mountain to the left of the aircraft?.

Well, Noumea has some substantial lumps on it. I didn't think to take the picture going past the big island later in the flight. Not only could you see the glow from the volcano, but the MORA goes up over 16,000 feet.

 

[harvyk]

Love the screenshots JB, thanks for taking them.

 

[petercr]

Like post # 11327... Looks like the Gregorys/UBD/Refidex of where to go once you get to LAX...

 

[jb747]

Interesting screen shots. How did you grab them?

We use an iPad for all of the paperwork...and it has a camera.

Also, with the line that I guess is your track, vector or whatever you call it, why are so many of them off at an angle to the direction of the "plane" symbol?

The direction the aircraft symbol is pointed is the heading. The track will be displaced from the heading by the drift.

 

[flyingfan]

Seeing the time remaining on the screens makes me wonder (and I think this has been asked before... forgive me as I can't find the answer): is that time until touchdown, stopping at the gate or something else?

Further regarding time: Would you normally expect just one update to that ETA, probably when you join the ATC queue near the destination? In my last few domestic flights the pilot has told us that ATC "has slowed us down by 6 minutes" or similar. Would you otherwise expect much change to the initial predicted time, apart from the usual expected factors like headwinds and weather; would ATC usually only slow you down once?

I've watched a video taken inside a commercial coughpit in which an alarm came on briefly (it might have been woop woop). Of course the pilots were completely composed and professional. How often do TCAS, terrain and those other noisy (which presumably mean significant) alarms come on in 'usual' flying? Are some airspaces and airports particularly prone to getting TCAS warnings?

Thank you

 

[andmiz]

Seeing the time remaining on the screens makes me wonder (and I think this has been asked before... forgive me as I can't find the answer): is that time until touchdown, stopping at the gate or something else?

The time on the screen you're seeing in JB's photos is the time at the next waypoint, in this case the latitude/longitude 18 south 170 east. The present time (in UTC) is also shown in a few different locations in the instrumentation.

Further regarding time: Would you normally expect just one update to that ETA, probably when you join the ATC queue near the destination? In my last few domestic flights the pilot has told us that ATC "has slowed us down by 6 minutes" or similar. Would you otherwise expect much change to the initial predicted time, apart from the usual expected factors like headwinds and weather; would ATC usually only slow you down once?

Once in the cruise and the FMC/FMGS is loaded with the predicted approach path for the destination, ETA is reasonably accurate; "subject to ATC". You may lose or gain a minute (maybe two) from unplanned altitude changes, and typically ATC will only slow you down once you're dealing with the destination's ATC, as they're the one's dealing with trying to slot you into an arrival sequence. So usually even on a long 16 hour flight, we can get very accurate with our ETA, up until destination ATC.

I've watched a video taken inside a commercial coughpit in which an alarm came on briefly (it might have been woop woop). Of course the pilots were completely composed and professional. How often do TCAS, terrain and those other noisy (which presumably mean significant) alarms come on in 'usual' flying? Are some airspaces and airports particularly prone to getting TCAS warnings?

Hard to tell what audible warning you heard, but it may have simply been the audible alert that the autopilot was being disconnected. TCAS warnings are rare, cautions can be more regular depending on the location (and usually only lead to an increased awareness and no real issue). Terrain; never.
Some airports are quite prone; our second busiest airport on the network has a busy general aviation airport very close to it, and its arrival/departure route is very close to ours. It's common to be scanning the sky for a Cessna flying alongside a few seconds after departure.

 

[mjt57]

JB, the missus is flying to the US on Monday on the 93. What route or track could it be going on when it departs?

I often hear jets overhead and I want to take a photo or two of the aircraft with a new telephoto lens that I've bought if it's going to headed my way.

Thanks.

 

[jb747]

JB, the missus is flying to the US on Monday on the 93. What route or track could it be going on when it departs?

I often hear jets overhead and I want to take a photo or two of the aircraft with a new telephoto lens that I've bought if it's going to headed my way..

There are three likely routes, and I won’t know until I get the plan. Most likely will be to head up over Albury towards Sydney. Have a look at FR24 for the previous day’s flight...that may give you an idea if the weather conditions are similar.

 

[mjt57]

Thanks JB. Won't do me much good then if it's up over A-W. I'll check out FR4 in any case.