Ask The Pilot

[jb747]

At high power settings you can also get a degree of blade rub. The blades actually stretch very slightly and in certain conditions can touch the casing. It’s common in new engines, and you can often see the marks it leaves when doing the preflight. A small amount of this sort of erosion is normal.

 

[Quickstatus]

What would be required from a flight control input/engine thrust perspective to land this. (It landed)
.

Was the vertical stabiliser remnant enough?

 

[ausfox]

Nasty, I don’t want to be on the throttles.

 

[justinbrett]

watched some of the Paris Olympics opening ceremony... pity about the rain.

the laser show from Eiffel Tower was impressive, and got me wondering if pilots get warnings (NOTAMS?) about shows like that ?

Well, not for this. It was temporary prohibited airspace with all civilian airports closed within 80 miles.

Paris’ plan for an airplane-free opening ceremony | Flightradar24 Blog

Air traffic restrictions around Paris for the Olympic games’ opening ceremony will keep airplanes far away.

www.flightradar24.com

 

[jb747]

What would be required from a flight control input/engine thrust perspective to land this. (It landed)
.
Was the vertical stabiliser remnant enough?

Most of the articles on this event are pretty shallow. I did read one a few years ago that tried to go into the aerodynamics of the event, but can't find it now.

The B52 is extremely unusual in that it has a very lengthy slab sided fuselage aft of the wing. This has the effect of attempting to straighten any sideslip. It also has landing gear that is only fuselage mounted, and can be extended differentially. In the image, the aft gear is down, but they haven't lowered the forward gear. There is also a small amount of speedbrake (mounted on the outer wing) extended. The gear and s/b are aft of the centre of pressure, and tend to keep the aircraft straight, though they don't have any stabilising effect in sideslip.

Wing anhedral (downward tilted as it moves outboard) is destabilising, and so has to be countered with increased yaw stability (big tail, and side slab fuselage). Whether the choice of anhedral wing came before the fuselage, or later (i.e. one countering the other), I don't know, but the upshot is that it has more directional stability than, say, a 747.

The stub tail would have helped, but it wasn't the only thing trying to keep it straight.

 

[Quickstatus]

Wing anhedral (downward tilted as it moves outboard) is destabilising

By reducing the keel effect (the centre of mass below the wings) which reduces the roll stability?
Interesting how all the heavy lift aircraft are all anhedral winged. What's the benefit? Increase manouverability?

 

[jb747]

By reducing the keel effect (the centre of mass below the wings) which reduces the roll stability?

No. It's to do with the way sideslip affects the local angle of attack on the wing. Keel effect was certainly relevant to this event, but it's not the reason for anhedral or dihedral per se. Note...anhedral isn't destabilising...it's just a lot less stabilising than dihedral. Wing sweep itself is very stabilising in sideslip, and that can lead to issues with excess stability and dutch roll.

Interesting how all the heavy lift aircraft are all anhedral winged. What's the benefit? Increase manouverability?

Packaging. You don't have heavy wing structure running through the bottom of the fuselage, so it's easier to have a nice low drive through fuselage. Also, of course, your wings are higher, which keeps the engines out of the way.

 

[Quickstatus]

It's to do with the way sideslip affects the local angle of attack on the wing

Sorry, my question was directed at the less stabilising effect of an anhedral wing.
AoA higher at the root - on the windward side compared with the leeward side??

I thought the F-4 effectively has a dihedral wing?

Packaging

There is that but putting that to one side, would an anhedral increase manouverability in an otherwise overly stable aircraft which had dihedral wing?

 

[p--and--t]

Not sure if this is the right thread, but would like to ask about BNE airport operation.

Can someone explain (ASIDE FROM WIND/WEATHER) why with two essentially parallel runways why planes can't take over the water on one runway and land over water on the other runway the majority of the time.

Asking as someone who puzzled why he gets woken at 5:30 ish every morning without fail by low flying landing aircraft and repeatedly can't hear the TV no matter how loud it is turned on from flight operations after 830 ish every night. Yet during the day there is significant less noise from flight operations.

 

[jb747]

Sorry, my question was directed at the less stabilising effect of an anhedral wing.
AoA higher at the root - on the windward side compared with the leeward side??

In the sideslip, the effective AoA of the wing (on the side to which you are slipping) with anhedral is less than that of a wing with dihedral. So, less lift, less restoring effect. Not considering effects along the wing (i.e. the root or tips), just the overall picture.

If you want to read up on an interesting wing planform, have a look at the Victor's crescent wing.

I thought the F-4 effectively has a dihedral wing?

Actually it's mostly flat, with a bit of dihedral at the tips. I was thinking of the tail, so mosty a brain fart.

There is that but putting that to one side, would an anhedral increase manouverability in an otherwise overly stable aircraft which had dihedral wing?

Manoeuverability is mostly turn rate, not roll related, so if you're going to relax the stability to help you'd do it in pitch. Fighters have huge roll rates anyway (300º per second is at the slow end of the scale, with some up around 720º/second).

 

[Quickstatus]

if you're going to relax the stability to help you'd do it in pitch.

Which is why some Fighters have canards in front of CoG?

Why pitch?. Shouldn't manouverability be affected by stability in all 3 axis of rotation?

 

[jb747]

Which is why some Fighters have canards in front of CoG?

I think that's more about control authority at low speeds, and very high AoA. Apparently also very bad from the stealth perspective. On the other hand, canards are more fuel efficient than having conventional tail surfaces.

Why pitch?. Shouldn't manouverability be affected by stability in all 3 axis of rotation?

Fighters already have such high roll rates that they can suffer from inertial ( or roll) coupling. In effect they become gyroscopes, with a control input translating itself through 90º and then appearing in a totally different axis. For that reason, there are limits placed upon allowed rolling manoeuvers at large control deflections. Relaxed roll stability would make this tendency worse, and for no benefit.

The way you manoeuver is to roll, then pull. So you roll to the bank attitude you want (pointing the vertical axis of your aircraft at the enemy's 6 o'clock), and then pull. Roll after that is at relatively low rates. High roll rates, coupled with pitch not only gives rise to coupling but you can also have rolling g issues, where the g loading on one wing far exceeds the load on the other. That's how you pull the wings off an aircraft.

 

[AviatorInsight]

Not sure if this is the right thread, but would like to ask about BNE airport operation.

Can someone explain (ASIDE FROM WIND/WEATHER) why with two essentially parallel runways why planes can't take over the water on one runway and land over water on the other runway the majority of the time.

Asking as someone who puzzled why he gets woken at 5:30 ish every morning without fail by low flying landing aircraft and repeatedly can't hear the TV no matter how loud it is turned on from flight operations after 830 ish every night. Yet during the day there is significant less noise from flight operations.

Here is an excerpt from BNE's Noise Abatement Procedures:

"From 2200 - 0600 Daily
1st Priority Landing = 19R and Take Off = 01R"

This is simultaneous opposite direction parallel runway operations (SODPROPS). I have used this in the past although it's seldom at BNE compared to SYD.

However...

"When traffic levels (my bold) and weather conditions allow, SODPROPS may be used at other times to achieve the best possible noise abatement outcomes. This is likely to occur during periods od low demand in the evening during the week, and evening and early morning at the weekend".

"Requirements for operating SODPROP are as follows:
• Visibility 8km
• Cloud base not less than 2500ft, and
• The runway conditions defined in Nomination of Runways clause"

Now, the nomination of runways clause goes on to say that if the runway is dry, then they will go with the runway that has the least amount of tailwind component <5kts. If the runway is wet, then they will go with the runway that has no tailwind component.

During night hours though, we are able to request an arrival on to 19L/R or departure off 01R when tailwind exceeds 5kts, even if the duty runway has no tailwind component.

So aside from the wind/weather requirement, the other is traffic levels. If there's a lot of demand during those hours, then they will not apply SODPROPS. Given the staffing shortages at Airservices at the moment, I'd say this would be the biggest reason that they aren't really using these procedures.

 

[jb747]

How did Airservices end up so short of staff?

 

[AviatorInsight]

How did Airservices end up so short of staff?

I’m sure JustinB might know more than me, but from a few friends who are now ex controllers, during COVID they let a whole bunch of people take redundancy and/or leave. When they’ve then tried to come back AS said no.

Now they’ve got to find a whole bunch of new controllers and wait out the time until they can get through the training and come on line.

It’s why we’re seeing a whole lot more of TIBA airspace in QLD in particular and TRAs in DRW, and MKY.

 

[Major]

While you are there AV, have you had any SIMs lately ?

 

[Warragul]

I’m sure JustinB might know more than me, but from a few friends who are now ex controllers, during COVID they let a whole bunch of people take redundancy and/or leave. When they’ve then tried to come back AS said no.

Now they’ve got to find a whole bunch of new controllers and wait out the time until they can get through the training and come on line.

It’s why we’re seeing a whole lot more of TIBA airspace in QLD in particular and TRAs in DRW, and MKY.

Air traffic controllers sacked for bullying and sexual harassment

It wouldn't surprise if some people behaving in ways outlined on this report were made redundant instead of dismissed or disciplined. It's easier to do in some cases although more $$ up front.

 

[AviatorInsight]

While you are there AV, have you had any SIMs lately ?

A couple of months ago, I had my first evidence based training sim. This has replaced our cyclic program (but it's still every 6 months). JQ and QF have been running these types of sims for years already and we have only now just caught up.

The big difference here is not to get a bunch of unrelated failures in a single sim session. Rather it's designed to be like a normal line flight with typical threats one might encounter in a single flight. The outcome is more of a competency based approach, where you can take as many goes as you need to get it right and still pass the sim.

I found it to be much more effective and really emphasises the training in the sim rather than just being the strict "this is a check and I'm not allowed to help" mentality from the check captains.

The other difference is that we kind of knew what was coming in the sim session. Now, the check captain has a list of about 7 -10 different scenarios and then at each point, will have another 5 or so different kind of event/threat/failure so give to the crew, so we have no idea what is coming (just like in the real world).

My sim started off at ROK for BNE at night. The scenario was that we had just come off an overnight and were taking over the aircraft from an inbound crew. So full checks were required. I noticed an issue with the cargo fire test and notified the captain who got the engineer to invoke the MEL so we could depart. The operational restriction was that no animals could be carried. So we needed to make sure it was reflected on the loadsheet. Of course when it arrived we not a notification that there was a dog in there. So we got that sorted out.

Normal start and taxi out. We had been given a SID when we requested clearance earlier but now the tower (checkie) told us that we needed to depart on a particular radial instead of the SID due to inbound traffic. So we sorted the aircraft out for that, re briefed and were ready for take off.

It was my leg, so I departed out on the radial and levelled off. Once the flaps were up we got a TCAS RA to descend with the conflicting traffic. Once clear, we started climbing away and cleared up to our cruising level of FL350. At about FL200 we got an airconditioning pack master caution light illuminate. I slowed my rate of climb right down and dealt with the issue. We found it was just the primary sensor and it was now working on the standby, so we continued climbing.

As we got closer to BNE we got asked to hold at SMOKA and due to an emergency at the airport, it was currently closed. We held for about 20mins (all in real time) before asking for an updated landing time so we could look at other alternates. We got told that there was no idea of when the airport would reopen.

We had enough fuel to get to MCY and so initiated a diversion there. Once we were on the way, the sim stopped and that was the end of the exercise.

The sim was then followed up with a bunch of V1 cuts (engine failures at take off) and a couple of engine out approaches and landing followed by a couple of box ticking exercises like unusual attitudes and circuits.

I've actually got upper air recovery training penciled in for next month in the MAX sim. This is basically aerobatics and recovering safely without breaking up the aircraft. A really good hands on sim and one of my favourites.

 

[justinbrett]

I’m sure JustinB might know more than me, but from a few friends who are now ex controllers, during COVID they let a whole bunch of people take redundancy and/or leave. When they’ve then tried to come back AS said no.

Now they’ve got to find a whole bunch of new controllers and wait out the time until they can get through the training and come on line.

It’s why we’re seeing a whole lot more of TIBA airspace in QLD in particular and TRAs in DRW, and MKY.

That is correct, but it's also a wider problem that's existed for a long time. It's not specific to Airservices, the problem also exists with RAAF controllers (and the two organisations poaching from each other, but mostly in one direction. It's not even specific to Australia, with similar problems in the US and UK and other countries.

In fact that's another reason, there was an issue with skilled work visas a few years ago which led to a lot of lateral recruits leaving.\

The culture sucks in both organisations, not helped by moving SYD TCU to MEL.

It takes a lot of time and money to recruit an ATC, and it's not really a sexy profession, so it's always an uphill battle. Then there's always a country overseas paying more.

 

[AviatorInsight]

The culture sucks in both organisations, not helped by moving SYD TCU to MEL.

It takes a lot of time and money to recruit an ATC, and it's not really a sexy profession, so it's always an uphill battle. Then there's always a country overseas paying more.

I’ve heard the SYD guys are really not happy about being moved to MEL.

To be honest it sounds very similar to working for an airline.