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RooFlyer

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Flight tracking website FlightRadar24 shows the service approaching Melbourne Airport just after 8am on Thursday morning. The flight dropped as low as 675 feet, the website indicated, and then rapidly ascended to 5000 feet after aborting the landing. The flight then circled the airport and landed safely just before 8.30am.
I think there is an auto 'landing gear not down' warning? When would that have kicked in?
 

jb747

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I think there is an auto 'landing gear not down' warning? When would that have kicked in?
There’s a couple of warnings that would kick in. Not sure of exactly where, but I’d expect at about 500’. It will vary with sink rate.

There would be a warning equivalent to “too low gear”, and another “too low flap”. One obviously means that all of the gear isn’t down and locked, whilst the other refers to a landing flap selection. You’d probably also have a warning if you selected a landing flap setting, prior to selecting the gear.
 

AviatorInsight

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I think there is an auto 'landing gear not down' warning? When would that have kicked in?
There is no hard altitude. It’s when the ground proximity warning system (GPWS) detects an unsafe terrain clearance at low airspeed with the gear up. I’d expect this to be going off by 600ft!
 

RooFlyer

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Thanks. If one of those warnings goes off in an Australian airline aircraft, in Australia of overseas, who finds out about it and how?

Is it mandatory for pilots to self report to ?airline / ?other; does the aircraft IT report it to some system that gets reviewed by someone else in the airline, etc?

Or isn't it a biggie?
 

AviatorInsight

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Thanks. If one of those warnings goes off in an Australian airline aircraft, in Australia of overseas, who finds out about it and how?

Is it mandatory for pilots to self report to ?airline / ?other; does the aircraft IT report it to some system that gets reviewed by someone else in the airline, etc?

Or isn't it a biggie?
Absolutely is a biggie! All the major airlines have some sort of quality assurance/flight data system, where by if certain criteria are exceeded (taxi speed, altitude final flap was set, bank angles, etc), the aircraft automatically will send a report to company. It then gets sent to a gatekeeper (a pilot) who looks at the data along with weather conditions and other factors and then determines if more investigation is needed. If we know there has been an exceedance then a report must be put in.

Whether the Vietnamese have anything internally like that I’m not sure...but now that the ATSB is aware they’ll obviously investigate it and will need to liaise with the company and crew.
 

opusman

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It sounded like it was ATC that spotted the gear wasn’t down. Was this just good luck? Or does someone watch all descending planes with binoculars checking for this?
 

mjt57

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The 94 was forced to land at Avalon today due to high winds at MEL. The pax were kept on the aircraft for nearly 3hrs.

Why couldn't they have been off-loaded and processed there?

Also, there are continuing stories about MEL's third runway.

What's better, a North-South or East-West runway?
 

ayebee

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According to FR24, todays QF 94 arrival was on final approach to MEL and at around 1200ft when the decision was taken to divert to Avalon.

Other arrivals immediately before and after were landing.

What would be the factors / process / trigger to make the diversion decision when the runway was in sight a few kms away and closer than the diversion airport ?
 
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jb747

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Thanks. If one of those warnings goes off in an Australian airline aircraft, in Australia of overseas, who finds out about it and how?

Is it mandatory for pilots to self report to ?airline / ?other; does the aircraft IT report it to some system that gets reviewed by someone else in the airline, etc?
Self reporting is a result of the airline's culture. Those that have a punitive response to mistakes, are unlikely to have a self reporting culture, and will be reliant upon automated systems.

All of QF's aircraft are fitted with recorders that grab data based upon various thresholds. Some are simply recorded to add to a database, whilst others will be flagged, and go to the safety department. This data is de-identified, and whilst the company might have a good idea of who did what, they can't say so for sure, and any punitive action based upon it would be extremely destructive, of what is a widespread safe culture.
 

jb747

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It sounded like it was ATC that spotted the gear wasn’t down. Was this just good luck? Or does someone watch all descending planes with binoculars checking for this?
ATC don't generally look for the state of the gear.

Whilst obviously an error on the part of the crew, this is being blown up. The aircraft would NOT have landed gear up. A couple of hundred feet lower, and the various GPWS warnings would have started to kick in. The aircraft knew the gear was retracted (or perhaps in transit), and it knows where it is and how high. It will become very upset. And loud.
 

jb747

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The 94 was forced to land at Avalon today due to high winds at MEL. The pax were kept on the aircraft for nearly 3hrs. Why couldn't they have been off-loaded and processed there?
Because:
a. Border Force staffing and rules.
b. Only remote parking and insufficient buses.
c. No ability to unload a 380 (no trained staff, etc).
d. I expect that most didn't want to go to Avalon anyway.

Also, there are continuing stories about MEL's third runway.
What's better, a North-South or East-West runway?
Well it would actually be nice if they built the place as it was supposed to be done back when it was first opened. Of course, much of that space has been used to provide space for all sorts of businesses unrelated to aviation.

If I have only one choice, I'd take north - south, but it has to be a decent length. Less than 3,000 metres is a waste.

According to FR24, todays QF 94 arrival was on final approach to MEL and at around 1200ft when the decision was taken to divert to Avalon.

Other arrivals immediately before and after were landing.
A bit like lemmings at a cliff?

What another aircraft does, on gusty days, is not relevant to you. He may not encounter anything of note, whilst the following aircraft runs into life threatening shear. Additionally, aircraft do not all behave the same way in poor weather. Of all the aircraft that I've flown the 767 was the best in nasty conditions. It had rapid control response, a lot of power, and a wing loading that was reasonably high. The 380 was probably the worst, as its wing loading when landing (weight per wing area) was low. Additionally, both the 380 and 747 offered the possibility of dragging an outboard engine on the ground.

What would be the factors / process / trigger to make the diversion decision when the runway was in sight a few kms away and closer than the diversion airport ?
Being in sight has nothing to do with it. If there is windshear, then it's dangerous. You can crash in good weather as well as poor. Melbourne 34 is prone to some very nasty undershoot shear, and is one of only a few places I ever encountered a windshear warning.
 

ayebee

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A bit like lemmings at a cliff?

What another aircraft does, on gusty days, is not relevant to you. He may not encounter anything of note, whilst the following aircraft runs into life threatening shear. Additionally, aircraft do not all behave the same way in poor weather. Of all the aircraft that I've flown the 767 was the best in nasty conditions. It had rapid control response, a lot of power, and a wing loading that was reasonably high. The 380 was probably the worst, as its wing loading when landing (weight per wing area) was low. Additionally, both the 380 and 747 offered the possibility of dragging an outboard engine on the ground.

Being in sight has nothing to do with it. If there is windshear, then it's dangerous. You can crash in good weather as well as poor. Melbourne 34 is prone to some very nasty undershoot shear, and is one of only a few places I ever encountered a windshear warning.
Thanks for replying.

Hopefully the decision of each of the pilots of the other planes is as valid as that of the A380 captain, rather than being a "lemming at a cliff" (a Disney myth).

I understand windshear can be very dangerous.

That the wing loading of the biggest aircraft is lower than smaller ones seems counter intuitive.
I imagine the lay person would assume the bigger the aircraft is more stable and resilient to turbulence. As a passenger I love the A380 as the the "quietest" ride down back.
Would be interesting if you could explain wing loading some more.
 

RSD

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Well it would actually be nice if they built the place as it was supposed to be done back when it was first opened. Of course, much of that space has been used to provide space for all sorts of businesses unrelated to aviation.

If I have only one choice, I'd take north - south, but it has to be a decent length. Less than 3,000 metres is a waste.
What was the original plan for Tulla?
 

RSD

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That the wing loading of the biggest aircraft is lower than smaller ones seems counter intuitive.
I imagine the lay person would assume the bigger the aircraft is more stable and resilient to turbulence. As a passenger I love the A380 as the the "quietest" ride down back.
Would be interesting if you could explain wing loading some more.
Much bigger heavier plane with four engines and a long range = a lot of fuel so have to have a wing loading at takeoff to handle that, A fuel capacity of 250 tons though means that the wing loading at landing is substantially less.
 

jb747

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Thanks for replying.

Hopefully the decision of each of the pilots of the other planes is as valid as that of the A380 captain, rather than being a "lemming at a cliff" (a Disney myth).
And many of the stories about aviation are myths too.

Even if only a few minutes apart, each aircraft can experience quite different conditions. The more gusty the conditions, the greater the likely difference. Limitations, especially crosswind, also differ across the aircraft types.

One story from quite some years ago. There was a very stormy, windy weekend in Sydney, and over the course of the weekend there were numerous go arounds. It was only after the event that someone at QF realised that 767-300s had been going around but not one 767-200. The difference? One type had a wind shear warning system, and the other didn’t.

That the wing loading of the biggest aircraft is lower than smaller ones seems counter intuitive.
I imagine the lay person would assume the bigger the aircraft is more stable and resilient to turbulence. As a passenger I love the A380 as the the "quietest" ride down back.
Would be interesting if you could explain wing loading some more.
The A380 has a truly enormous wing area. The aircraft was originally designed with stretches to well over 600 tonnes planned.

This is all you never wanted to know about wing loading.

The upshot for a 380 landing is that the wing loading at that time will be about half what it was at take off. That means that the aircraft will create (or lose) a greater effective amount of lift for any wind gust. That makes it move around quite a bit from the pilots’ perspective. Couple that with a lot of inertia, and relatively slow control response, and it makes poor conditions harder work than you might expect. Ride quality in an aircraft is affected my many things, and in a large aircraft like the 380, the large potential amount of wing flexing acts as a shock absorber....that’s the main reason that passengers like the way it rides.
 

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