Ask The Pilot

[jb747]

Historically, lightning was more an inconvenience than anything else. It did little (pretty much zero) harm to legacy aircraft. I’ve been hit numerous times, including one memorable flight to the old HK, where we took about half a dozen strikes whilst trying to get in before the typhoon arrived (landing wasn’t the issue but traffic was holding all over the place). The 767 simply didn’t care.

For some contrast though, this is a 787 hit.

Lightning Strike Forcibly Separates Fuselage Of American Airlines 787 - View from the Wing

Photos of damage to the fuselage of an American Airlines Boeing 787-9, registration N839AA, caused by a lightning strike, are spreading through social media. The incident occurred on Monday's Tokyo Narita to Dallas - Fort Worth flight. The plane, originally delivered in October 2018, has been...

viewfromthewing.com

 

[flyer89]

Historically, lightning was more an inconvenience than anything else. It did little (pretty much zero) harm to legacy aircraft. I’ve been hit numerous times, including one memorable flight to the old HK, where we took about half a dozen strikes whilst trying to get in before the typhoon arrived

So beers that night?

 

[equus]

3 litres, per person per hour within the potable system (max 2,000 kg). So, that would mean roughly 1,500 liters carried (250 people on a 20 hour sector).

Factor of 10 issue here? 3 litres per hour for 20 hours is 60 litres per person. 60 x 250 = 15,000 litres.. If there is a maximum of 2,000kg, then it can't be 3 litres per person per hour, as the 2,000 litres. With around 500 people +/- on an A380, that comes out at 4 litres or so per person total.

 

[jb747]

Factor of 10 issue here? 3 litres per hour for 20 hours is 60 litres per person. 60 x 250 = 15,000 litres.. If there is a maximum of 2,000kg, then it can't be 3 litres per person per hour, as the 2,000 litres. With around 500 people +/- on an A380, that comes out at 4 litres or so per person total.

This is what I actually wrote, so I think my decimal is in the correct spot. But, you're right in that the total amount is enough for a couple of good cups of tea.

Using the 380 system as an example, there was about .3 litres, per person per hour within the potable system (max 2,000 kg). So, that would mean roughly 1,500 liters carried (250 people on a 20 hour sector).

 

[equus]

Oops, my bad missed the . hiding in the screen - too used to seeing that written as 0.3 to avoid such potential embarrassing mis-reads.

 

[mt63]

A few years ago I was part of 2 lines of planes at Sydney that had come to a standstill while a storm passed through. We got quite a buffering and I thought it would be prudent that flaps would be withdrawn, but none did. After all, It is known that storm winds are unpredictable in both strength and intensity.

 

[Mattg]

I was on NZ129 today. In his pre-flight announcement, the captain said that they had received weather forecasts from two independent sources - one indicated that it would be bumpy most of the way, while the other indicated smooth flying conditions. He said he wasn't sure which forecast would be correct, but thankfully it was the latter.

Where do you get your weather forecasts from, and is there any reason two different forecasts would be so different?

 

[jb747]

A few years ago I was part of 2 lines of planes at Sydney that had come to a standstill while a storm passed through. We got quite a buffering and I thought it would be prudent that flaps would be withdrawn, but none did. After all, It is known that storm winds are unpredictable in both strength and intensity.

If there was any chance of the wind being so strong that the flaps would matter one way or the other, then I’m sure that you wouldn’t have been in the aircraft at all.

Retracting the flaps (or more correctly, delaying their extension) is sometimes done if taxying in some icing conditions.

 

[jb747]

I was on NZ129 today. In his pre-flight announcement, the captain said that they had received weather forecasts from two independent sources - one indicated that it would be bumpy most of the way, while the other indicated smooth flying conditions. He said he wasn't sure which forecast would be correct, but thankfully it was the latter.

Where do you get your weather forecasts from, and is there any reason two different forecasts would be so different?

There are many sources, some of which overlap. Most national forecasters put out predictions for their areas (i.e. the BoM or American NWS). In flight, we get weather from automated broadcasts (VOLMETS) or data link, both of which come from the national forecaster. At the flight planning state, integrated world wide forecasts come from companies like Jeppesen, though they are still getting most of their data from the national forecaster. I suspect you could probably just ask ChatGPT these days.

Indications of bumpy or smooth, were, in my opinion, not worth the ink used to print them. They appeared on our flight plans as ‘shear rates’ (just a number from 1 to 9). These days, the application windy.com probably gives data as good as the official sources.

 

[justinbrett]

is there any reason two different forecasts would be so different?

This is more of a met question than a aviation question, but there are multiple weather models used for forecasting, and they don't always agree. If one source uses model A, and the other uses model B, they can have vastly different forecasts.

Explainer: computer weather models - Social Media Blog - Bureau of Meteorology

The Bureau of Meteorology's blog gives you the inside information on weather, climate, oceans, water and space weather.

media.bom.gov.au

 

[jukebox333]

On a transcon flight a couple of weeks back, we were late out of the gate by an hour, so missed our arrival slot for PER.

Just after making landfall near Esperance, PER ATC told the pilot he needed to slow down his approach to get us into the queue for landing. To do this, the pilot performed a series of turns that took as quite a way off the direct line:




Question; why do these manoeuvres, rather than just throttle back the engines and fly slower to lose time?

 

[jb747]

On a transcon flight a couple of weeks back, we were late out of the gate by an hour, so missed our arrival slot for PER.

Just after making landfall near Esperance, PER ATC told the pilot he needed to slow down his approach to get us into the queue for landing. To do this, the pilot performed a series of turns that took as quite a way off the direct line:

Question; why do these manoeuvres, rather than just throttle back the engines and fly slower to lose time?

Normally aircraft have very little margin for going faster or slowing down, when in the cruise. If you slow by more than about 15 knots, you’ll get below your min drag speed, with the result that you may have insufficient power to stop the aircraft from continuing to lose speed. At that point the only way to regain the speed is to trade off some height. So, to fly slower, you’ll first have to fly lower, so not only will you lose time, but as the fuel burn will be higher, you’ll also lose a disproportionate amount of fuel. It’s most efficient to remain at altitude and your best speed and to add some miles.

The FMCs don’t do that calculation very well, especially if it is going to encompass the descent point (as it does here). There’s also a bit of trigonometry involved. A technique that the RAAF taught for students on low navs who needed to lose time (they were given target times to the second) involved turning off track by 60º, and then turning back 120º to regain it. That draws an equilateral triangle, so you’ll lose time equal to the length of the off track leg. ATC often use a variation of this.

It’s likely that the aircraft also descended at a slower speed than usual. Transitioning to 250 knots early in the descent, rather than at the usual 10,000’ also loses quite some time, without too much of a fuel penalty. The time lost is greater than you’d expect, because the 250 knot descent leaves the cruise quite a bit earlier, and as the entire descent profile is lower your IAS converts to a lower TAS for longer.

 

[jukebox333]

Thanks for the comprehensive explanation, JB!

 

[jase05]

Any comments on this @jb747 or any similar experiences?

 

[jb747]

Any comments on this @jb747 or any similar experiences?

I‘ve seen radar noise jamming in the India/Pakistan region. Anyone who is playing with GPS is not benign. 121.5, depends where it is. The last ships I heard making a pest of themselves on guard were USN.

 

[justinbrett]

Any comments on this @jb747 or any similar experiences?
View attachment 319365

Interesting. If this order was from a RAAF flying squadron it would be classified secret and divulging this to the public would be an offence probably leading to imprisonment.

I get it’s civilian but surely it’s bad form for the QF member to be passing this around.

 

[RooFlyer]

I get it’s civilian but surely it’s bad form for the QF member to be passing this around.

Does it being on the internet make any difference?

MSN

Qantas warns its pilots of VHF interference by stations claiming to represent the PLA in the South China Sea and western Pacific.

Qantas Group aircraft have experienced interference on VHF from stations purporting to represent the Chinese Military in the western Pacific and South China Sea. The airline updated its flight standing order manual on Thursday to include policies on what to do if crews encounter interference...

fl360aero.com

 

[justinbrett]

Does it being on the internet make any difference?

MSN

I'm talking about the person who leaked from QF to the internet, not Jase for posting it. It's all over the media now.

 

[jb747]

It’s operational information, that I’d expect CASA and the various other aviation authorities to be issuing NOTAMs about, and if they haven’t, then why not. It was just as likely leaked from the top as anywhere else. None of this is confidential in any way, nor did the company ever try to make it so.

 

[Saab34]

AV, do you reference third party flight tracking flights like FR24, or one of the others, while on shift for any useful means? I was sitting up front on a Rex flight recently and I noted the pilot checking FR24 and OzRunways before we departed, I assume checking for any unverified traffic in the local area?