Ask The Pilot

[Quickstatus]

I don’t think the generators directly produce DC, but there are various transformer/rectifiers throughout the system. I’ll have a look at a manual when I get home in a day or two.

The A330 emergency generator produces power from a small propellor dropped into the airstream. Not sure where it is...on the A380, it’s under the port wing.

Some aircraft can also produce power from what are called HMGs....generators within the hydraulic system.

Yes Sorry. My misread. Sounds like the A330 emergency gennie is driven either by one of the hydraulics or by RAT hydraulic

Are all RATs hydraulic?.
I read that the A380 RAT is nearly 6 feet diameter

 

[AviatorInsight]

Harking back to an off-hand comment about the attitude of some US air traffic controllers, do any SIMs include a degradation or complete loss of ATC comms into a busy airport?

On the approach chart will be a little box that has the lost comm procedure in it. You basically follow that as prescribed, squawk 7600 and then follow it to the most appropriate runway.

Pretty easy really. Where people become stuck is actually talking to ATC with what they want things like medical priority required, fuel, and DGs on board, etc. So we practice that in the sim.

 

[AviatorInsight]

Yes Sorry. My misread. Sounds like the A330 emergency gennie is driven either by one of the hydraulics or by RAT hydraulic

Are all RATs hydraulic?.
I read that the A380 RAT is nearly 6 feet diameter

All RATs that I know of produce hydraulic power. If you mean the time between power loss and RAT Deployment, then the batteries are used to automatically extend the RAT until sufficient rotations is achieved to develop its own power. In the sim at least it was always pretty quick.

 

[Quickstatus]

Thanks I had misread that the gennies at least in the A330 were: one in each engine, APU, emergency gennie AND RAT.

 

[jb747]

Harking back to an off-hand comment about the attitude of some US air traffic controllers, do any SIMs include a degradation or complete loss of ATC comms into a busy airport?

It comes up in some sims. Last I recall, it was done in London. Basically all you really have to do is remain predictable.....

 

[flyer89]

It comes up in some sims. Last I recall, it was done in London. Basically all you really have to do is remain predictable.....

I assume one doesn’t have to make a flypast of the tower and rock the wings to comply with the flashing lights in an A380? As much as I’d like to see it.....

 

[jb747]

Yes Sorry. My misread. Sounds like the A330 emergency gennie is driven either by one of the hydraulics or by RAT hydraulic

Are all RATs hydraulic?.
I read that the A380 RAT is nearly 6 feet diameter

The 380 RAT tucks away in one of the port flap fairings. When running it only provides about 7% of the normal power.....just about nothing works.

RATs come in many styles. Some provide only electrics. Some only hydraulics, and some are a mix. So, whilst the 380 is electrics only, the 767 was only a very limited subset of the flight control hydraulics.

 

[jb747]

All RATs that I know of produce hydraulic power. If you mean the time between power loss and RAT Deployment, then the batteries are used to automatically extend the RAT until sufficient rotations is achieved to develop its own power. In the sim at least it was always pretty quick.

There are variations on that theme too.... In the 380, there’s a backup flight control system, separate to the six flight control computers, that is run by a hydraulic driven generator in the gap before the RAT runs up.

 

[jb747]

I assume one doesn’t have to make a flypast of the tower and rock the wings to comply with the flashing lights in an A380? As much as I’d like to see it.....

No. You fly an approach and land. If you get some green lights that’s nice...but as long as there aren’t any reds.

I’ve seen the comms go out twice in my airline time. Both occasions in Singapore, after lightning strikes. On the first occasion, I was thankfully on the ground, waiting to taxi. To say that it was mess would be a major understatement. It took hours to clear up. The other time, we were on finals, when there was a strike on the tower, and they disappeared off the air. I intended landing anyway, but we actually got a green from them as we neared the ground.

 

[Melburnian1]

Noticed QF72 being mentioned recently in this thread.

Not sure if the resident pilots have seen this from the Perth Now website a couple of days ago. But worth a read.

'The plane went psycho': captain | Perth Now

We don't often quote two year old posts as a reference, but this additional information (book extract: on sale in the next couple of weeks) has been published today by Nine Group (former Fairfax) papers.

The photo of the aircaft cabin showing the damage was probably published previously but it remains confronting to think that people went through it. Hard to comprehend.

The story must be appearing in 'Good Weekend' (magazine) on Saturday 18 May but to maximise viewership/readership it's online today:

'I’ve become very isolated': the aftermath of near-doomed QF72

Faced with a mid-flight computer failure, a captain had only seconds to steer his plane to safety. It took much longer to work through the mental fallout.

www.brisbanetimes.com.au

I wonder how many copies the book will sell.

The emotions described are hard to understand unless one's been there, experienced that, and I haven't. One of AFF's (former) aviators has described in the past how Airbus planes are broadly more automated, if I recall, than competitor Boeing's offerings.

Which aircraft rego was this and at the time for how long was it out of revenue service? (I've not read the ATSB report).

 

[jb747]

Kevin was a very good pilot, and they are lucky that he was the Captain on the day. His reputation as a cough magnet was well deserved though....pure luck brought him more than his share of unusual events, all of which he handled well. I expect his book will be a better read than the competition.

I have no idea what the aircraft registration was. It didn’t achieve all that much g...nowhere near the limits. But any negative g is a nasty thing in an airliner. Big difference from this event and the MCAS that we’ve spent so much time on lately is that the inputs were not sustained. There were two very solid nose down inputs, lasting only a second or two. The system itself then realised that it was in error and reverted to a lower law that inhibited anything further.

The fact that no matter what happens, the 300 people behind the coughpit door are depending upon you, is something that sits at the back of your mind. Doctors only kill their patients one at a time.

 

[Melburnian1]

Kevin was a very good pilot...I expect his book will be a better read than the competition...

Is someone else writing a book on the same subject?

 

[oz_mark]

Which aircraft rego was this and at the time for how long was it out of revenue service? (I've not read the ATSB report).

QPA (Investigation: AO-2008-070 - In-flight upset - Airbus A330-303, VH-QPA, 154 km west of Learmonth, WA, 7 October 2008 if you're so inclined!!)

Is someone else writing a book on the same subject?

Or possibly another event?

 

[jb747]

This is interesting reading...

ENG09IA011: Full Narrative - NTSBhttps://www.ntsb.gov/_layouts/ntsb.aviation/brief2.aspx?ev_id...ntsbno...1

 

[Quickstatus]

So a little piece of foreign object interfered with the elevator control?

 

[mikenz]

Does a plane decelerate when it reaches cruise altitude?

 

[mikenz]

Are pilots aware of Loon balloons and other high altitude objects? Do they ever come close to common flight paths?

 

[jb747]

Does a plane decelerate when it reaches cruise altitude?

From the speed it was climbing at? No. During the climb, the climb target should slowly converge on the cruise speed.

But, as the aircraft burns fuel, and becomes lighter, the most efficient speed will slowly reduce. It's actually an angle of attack, so as the aircraft becomes lighter, less alpha is needed to maintain the appropriate lift. So, by slowing slightly with weight reduction, that best alpha can be maintained.

 

[jb747]

Are pilots aware of Loon balloons and other high altitude objects? Do they ever come close to common flight paths?

You do sometimes see NOTAMS listing balloon flights. Generally they are far above the airways. A friend who flies the 787 put up a picture a few months ago, of a TCAS paint of balloon in the middle of the Pacific (well above him though).

I have seen unnotified balloons right in the airways though. Saw about 5 in just a few minutes on one occasion, roughly over Indonesia.

 

[Aus ATC]

There are quite a few Loon balloons currently operating north of Alice Springs - not sure why there are congregating there. They can operate without clearance above FL600 (that is uncontrolled airspace) and they spend most of their time up there. They can request (and generally obtain) clearance to operate FL500 and above. They also need to cut down from time to time - we coordinate that and separate them from aircraft in controlled airspace. It certainly helps that they have ADS-B installed.