Ask The Pilot

[moa999]

What's your worst whim of the gods experience?

Presumably something like a plane going tech in DXB once you have signed in could put you beyond hours pretty quickly, and result in a couple of extray days on that pattern?

 

[jb747]

What's your worst whim of the gods experience?

Presumably something like a plane going tech in DXB once you have signed in could put you beyond hours pretty quickly, and result in a couple of extray days on that pattern?

I've not really had many bad experiences over the years. Being turned around when most of the way home (Singapore and Bangkok), and sent back to London made for a very long trip. Been caught by the typhoons in HK a couple of times. I don't recall ever running out of hours and having to pull the pin because of that.

 

[Skyring]

This time of year in Canberra the smart travellers head to the airport before dawn so as to catch the first planes out. They have been on the ground all night, and can launch in the fog, but the next flights out have to land, and they can't do that in fog.

At least that's the story, and it seems to match what I observe.

Now I hear that there's something called "freezing fog" which prevents takeoffs. Is this a thing?

 

[AviatorInsight]

Now I hear that there's something called "freezing fog" which prevents takeoffs. Is this a thing?

Yes it definitely is a thing. Basically the water droplets are 'supercooled'. That is where the droplets are still in the liquid state until they freeze on impact with a surface. This is a bad thing for any aircraft.

 

[Boris spatsky]

Yes it definitely is a thing. Basically the water droplets are 'supercooled'. That is where the droplets are still in the liquid state until they freeze on impact with a surface. This is a bad thing for any aircraft.

Certainly the issue with freezing fog in Australia is the Hold Over Time of the de-icing fluid. That is, the number of minutes after commencement of application of the de-ice fluid until you need to be airborne.

Freezing fog Hold Over Time can be in the vicinity of 10-12 minutes with type 1 fluid (and you don't get types 2 or 4 in Oz for RPT that have longer HOTs). A narrow body jet takes about 10-15 minutes to de-ice, so straight away if there is freezing fog you can't get airborne at all, even if you de-ice.

 

[mannej]

Just found this one one Avherald - Incident: Singapore B772 at Canberra on Feb 22nd 2017, descended below minimum safe altitude

Surprised not to hear of this one considering previous busted minimum incidents in the last few years. Would you rate this in the league of the D7 or the TT incidents, or a minor incident?

 

[Boris spatsky]

Just found this one one Avherald - Incident: Singapore B772 at Canberra on Feb 22nd 2017, descended below minimum safe altitude

Surprised not to hear of this one considering previous busted minimum incidents in the last few years. Would you rate this in the league of the D7 or the TT incidents, or a minor incident?

It's an interesting one - there have been a few cases of descent below lowest safe altitude into Canberra in recent years. QANTAS 737 did it (autopilot mode was different to expected). High terrain to the south can easily lead you to getting higher than a normal profile on some of the runway 35 approaches with the resulting mindset of 'i really need to get down'.

I am not a 777 guy but in this instance it may not be dissimilar to the 737 where is you have a STAR and a runway approach loaded then change the runway approach without reselecting the STAR it can dump the altitude constraints (that protect you in VNAV autopilot mode) depending on what version of the FMS software you have. It will be interesting to see what the ATSB investigation findings are.

 

[andmiz]

It will be interesting to see what the ATSB investigation findings are.

The quoted AVherald is reporting upon the final ATSB investigation. It was a FMC approach edit which led to an alt constraint not being present.

 

[Boris spatsky]

Ahh yes sorry i skim read it... yes a manual entry of an approach waypoint by the Captain. Sounds like there may have not been a cross check either by the other pilot.

 

[Melburnian1]

One of our aviators may have answered this months or longer ago so my apologies if it is repetitious.

Allegedly on Monday evening 1 August VA86 was delayed as reported in this Facebook post:

In J On va86 tonight Hong Kong to Melbourne tonight and Virgin have taken the decision to delay the departure by 2 and a half hours as there is a threat of fog at Melbourne in the morning. Very disappointed as Iv had to cancel half a mornings work as a result. The VA Facebook team have confirmed the reason and it was to avoid ' possibly having to divert to another port'. Qf30 and cx105 on the other hand are departing on time and seem to be willing to absorb the costs of a possible diversion. Would greatly influence me in future to fly the competitors as I this delay has cost me business and money. I feel this decision is more one that would be made by a LCC than a premium airline. Thoughts ?

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In the end, fog did not prevent landings in MEL as far as I know.

In these circumstances, when an aircraft is on the ground, who decides to delay it: the Captain or the airline's operations department in the airline's home country?

 

[jb747]

I feel this decision is more one that would be made by a LCC than a premium airline.

In my experience, it's the other way around. The LCCs always go. Saying no is often the best outcome in aviation.

In the end, fog did not prevent landings in MEL as far as I know.

In these circumstances, when an aircraft is on the ground, who decides to delay it: the Captain or the airline's operations department in the airline's home country?

I've said it before, but on a given day, at a given airport, not all aircraft are equal. There are many reasons why an aircraft may, or may not, have been able to fly the approach. There was fog according to the weather records, so any aircraft flying there would have needed an alternate. It would also have needed CAT II capability at the minimum. What was the MEL status of the aircraft? How many crew was it operating with? There's a very long list of items that could affect the planning and outcome of a flight.

The decision to delay would most likely have been made by the operations department, before the crew even left the hotel.

 

[serfty]

...
In the end, fog did not prevent landings in MEL as far as I know.
...

Perhaps a better word than prevent may be "delayed".

In any case, QF94 is currently on the ground in SYD.

...and QF30 is showing as arrived 7:15am.

 

[mjt57]

So, still no Cat III ILS in MEL???

 

[docjames]

One of our aviators may have answered this months or longer ago so my apologies if it is repetitious.

Allegedly on Monday evening 1 August VA86 was delayed as reported in this Facebook post:

In J On va86 tonight Hong Kong to Melbourne tonight and Virgin have taken the decision to delay the departure by 2 and a half hours as there is a threat of fog at Melbourne in the morning. Very disappointed as Iv had to cancel half a mornings work as a result. The VA Facebook team have confirmed the reason and it was to avoid ' possibly having to divert to another port'. Qf30 and cx105 on the other hand are departing on time and seem to be willing to absorb the costs of a possible diversion. Would greatly influence me in future to fly the competitors as I this delay has cost me business and money. I feel this decision is more one that would be made by a LCC than a premium airline. Thoughts ?

-----------------------

In the end, fog did not prevent landings in MEL as far as I know.

In these circumstances, when an aircraft is on the ground, who decides to delay it: the Captain or the airline's operations department in the airline's home country?

Interesting, i'd rather wait 2hrs in the lounge n HKG then have certainty of arrival at my destination (even if it is 2hrs late), than have to divert which will typically cost > 2hrs.

The fog in MEL this am has caused signifcant delays / diversions.

 

[flychrisfly]

In lightly loaded flights does it matter where the pax sit? If so, how is this coordinated and are the pilots involved or at least informed?

 

[jb747]

So, still no Cat III ILS in MEL???

Melbourne has a Cat III ILS on 16, as well as GLS on 16 (and I think 27). That means that if you can get to the point of legally flying the approach, you'll almost certainly get in (assuming aircraft/crew/etc are appropriately qualified). The problem is getting to the point where you can fly the approach. You will either need very substantial holding fuel, or a full alternate. That's most likely not an issue if you weren't weight limited on departure, and the weather was on the forecast. Very long range flights that regularly take off at their max weight rarely have such luxuries.

 

[mjt57]

Melbourne has a Cat III ILS on 16, as well as GLS on 16 (and I think 27). That means that if can get to the point of legally flying the approach, you'll almost certainly get in (assuming aircraft/crew/etc are appropriately qualified). The problem is getting to the point where you can fly the approach. You will either need very substantial holding fuel, or a full alternate. That's most likely not an issue if you weren't weight limited on departure, and the weather was on the forecast. Very long range flights that regularly take off at their max weight rarely have such luxuries.

OK, so you just can't turn on the auto-land system, point it to the appropriate runway and let it do its thing on a flight from LAX or DXB, then?

What is this point and what do you mean by "legally flying it"?

These diversions which occur at MEL must cost the airlines a fortune.

 

[andmiz]

OK, so you just can't turn on the auto-land system, point it to the appropriate runway and let it do its thing on a flight from LAX or DXB, then?

What is this point and what do you mean by "legally flying it"?

These diversions which occur at MEL must cost the airlines a fortune.

The problem is getting to the point where you've met the regulatory requirements for the aircraft, airline ops, weather, alternates and fuel. An Australian carrier like VA may not carry fuel to reach an alternate if weather at the destination is 'good enough', whereas it's otherwise generally international standard to always carry diversion fuel. If it's indicating fog like it was on 01AUG (PROB30 0111/0201 0500 FG BKN002) then fuel to hold until after 11AM or fuel to divert is required to be carried. They may have had weight restrictions preventing them from carrying the additional fuel required because it's not a standard every-day practice, so a 2 hour delay was required to reduce the amount of holding fuel required.
Other factors which may have influenced the decision and prevented them to be legally able to fly the approach could have been aircraft defects prohibiting low vis or autoland operations, aircrew recency on those operations, airline approvals/authorisations or airfield equipment outages.

 

[jb747]

In lightly loaded flights does it matter where the pax sit? If so, how is this coordinated and are the pilots involved or at least informed?

Weight and balance is accounted for down to the last passenger. Whilst the effect of one person moving a couple of rows is tiny, it's quite possible that it would be enough to move a load that was near the limit, over the line.

We won't let you move fore and aft for take off. Laterally we don't care.

 

[jb747]

OK, so you just can't turn on the auto-land system, point it to the appropriate runway and let it do its thing on a flight from LAX or DXB, then?

Aviation is all about options. We do everything possible to keep as many options open as possible. Fuel is the greatest giver of options, because it allows the luxury of time (or miles). Departures from LA to Melbourne do not have an alternate to destination as a matter of course. If the weather is good, that's a waste of about 10 tonnes of capacity, that is rarely needed. This only becomes relevant towards the end of the flight, as for the most part of the journey, you have the choice of many airports within (potentially) thousands of miles. In fact, for most of the journey, you'd be dumping many tonnes of fuel if you had to go anywhere else.

Departures from LA (to Melbourne) are almost always at maximum brakes release weight. The chances are that we simply cannot carry any holding or alternate requirements for Melbourne, without offloading a large number of passengers. And most likely we won't actually need the fuel at the end, as the prediction that we have to use is about 20 hours into the future..they get better as you get closer. So, in simple terms (shock, horror), we may depart LA without sufficient fuel for the mission.

But....

Along the way there are a number of primary alternates, with the last one being Sydney. As long as we keep our fuel reserves above the line for any point that we could use (at all times, with no gaps), we can continue. If you can keep it above the line to destination, then you get to go there.

These diversions which occur at MEL must cost the airlines a fortune.

I'm sure they do. But that's actually cheaper than carrying "fill 'er up" fuel everywhere. How often do we miss out? In 32 years of airline flying, and untold numbers of LAX-MEL, I've diverted once. Come close a few times, but doing those numbers (over and over) is part of the job.