Ask The Pilot

[jb747]

Hi pilots, there is an article in the NZ Herald about two aborted take offs in a row by the same plane
'We're not crash-test dummies': Kiwi flyer tells of horror aborted takeoffs.
While it is bit hysterical, can you shed any light on whether there is cause for concern about MH's maintenance standards from this?
Cheers

A bit hysterical. That's an understatement. This is an article that is almost totally devoid of facts. Just find the loudest passenger, and talk to them. And only them.

Flight MH145D barrelled down the runway at full throttle but just as the wheels were about to lift off, the pilot slammed on the brakes and the plane came to a juddering halt, a passenger claims.

Which bit did the passenger claim? The entire statement, or just the bit where it stops.

"Full throttle".

Unlikely. It would have been strongly derated.

"As the wheels were about to lift off".

No, V1 is going to be appreciably less than V2.

"The pilot slammed on the brakes".

Again no, the brakes are applied automatically by the RTO system.

"Juddering halt".

Possibly.

"Passenger Serjit Singh, of Red Beach, said as they skidded to a stop he thought another plane was coming into land and thought it was going to crash into them."

Ah, I'm going to worry about stuff that I just made up.

"I was in utter shock and disbelief.

Probably.

The exact same issue that was meant to have been fixed was not and the lives of all passengers and crew on board were risked.

Well, as we are never told in the article why the abort happened, I have to wonder if passenger X even knew, or understood. The aircraft aborted twice. Perhaps the cause was the same, perhaps not. But, we don't know. Does he?

Whilst I have never had a double abort, they aren't all that uncommon. Most pilots use something along the lines of "I will abort for any warning or caution up to 100 knots". Once an abort is started, it won't be discontinued. So, abort, come off the runway, and look at the system. If the fault hasn't been latched by the warning and caution system, and the brakes aren't too hot, you may actually be able to legitimately go again. The fault may, or may not recur. Taking it back to maintenance can have the same outcome. It's not bad maintenance. Bloody awful reporting though.

 

[cambriamarsh]

Thanks JB, the NZH has really gone backward of late.

 

[flyer89]

Passenger Serjit Singh, of Red Beach, said as they skidded to a stop he thought another plane was coming into land and thought it was going to crash into them.

I think this fellow might need some help with his generalized anxiety. That’s some pretty serious catastrophizing.

 

[flychrisfly]

A go around can be carried out up until the point that reverse thrust is selected, so it could be initiated from the ground, although the window for doing so is tiny, as reverse is selected immediately upon touchdown.

When is 'touchdown'? Is it the point the full main gear (as in, all the wheels) touch the ground or does the nose gear also need to be planted? Thanks

 

[jb747]

When is 'touchdown'? Is it the point the full main gear (as in, all the wheels) touch the ground or does the nose gear also need to be planted? Thanks

For the purposes of reverse actuation, it's weight on the main gear. The nose gear doesn't have to be on the ground, and some pilots hold it off for quite a while (which is a silly party trick).

 

[flychrisfly]

For the purposes of reverse actuation, it's weight on the main gear. The nose gear doesn't have to be on the ground, and some pilots hold it off for quite a while (which is a silly party trick).

So, will the reverse thrusters deploy without weight on the main gear? Do pilots know by sensing the sink stop and the contact with the runway or is there an indicator?

 

[jb747]

So, will the reverse thrusters deploy without weight on the main gear? Do pilots know by sensing the sink stop and the contact with the runway or is there an indicator?

No, reverse thrust is unable to deploy without weight on the wheels. That's one of the safety switches to stop Lauda type events. The nose gear is not part of this, and that's what some pilots hold up for a while. Pointless trick as far as I'm concerned.

From the pilot's point of view, we feel the aircraft touch down. The levers should already be at idle at that point, if not close them. The reverse thrust levers are on the front of the normal levers, and have to be lifted up and back to control reverse. You apply a little pressure against them, and they'll go a short way, and stop. As long as there is weight on the wheels, and the forward thrust levers are at idle, this will initiate the engine cowls moving to the reverse position. When they reach that position, the lock releases, and the levers will move into the reverse range.

 

[AviatorInsight]

So, will the reverse thrusters deploy without weight on the main gear? Do pilots know by sensing the sink stop and the contact with the runway or is there an indicator?

Speedbrake activation is done automatically by the weight on wheels switch. A call by the PM “speedbrakes up” further identifies that the aircraft is actually on the ground, along with the fact that runway overruns are possible without it deploying so it’s also a confirmation call to the PF. After this call we then reach for the reverse thrust levers.

 

[jb747]

Speedbrake activation is done automatically by the weight on wheels switch. A call by the PM “speedbrakes up” further identifies that the aircraft is actually on the ground, along with the fact that runway overruns are possible without it deploying so it’s also a confirmation call to the PF. After this call we then reach for the reverse thrust levers.

Interesting procedural difference. The call in the A380, was "ground spoilers, reverse green, brake (whatever it was set to), and decel (if you can feel it)". This call came in one hit, after everything was done. You only waited for the interlock to release. Reverse selection will also activate ground spoilers if they haven't already happened.

 

[AviatorInsight]

Interesting procedural difference. The call in the A380, was "ground spoilers, reverse green, brake (whatever it was set to), and decel (if you can feel it)". This call came in one hit, after everything was done. You only waited for the interlock to release. Reverse selection will also activate ground spoilers if they haven't already happened.

That is an interesting difference although we’re making the calls a lot further apart. “Speedbrakes up, reverses normal (once the sleeves are fully open and showing green), autobrake disarm (indicated by the caution light when the PF kicks it out), 60kts”. Some captains will add thrust once on the rapid to bring the speedbrakes back down, rather than reaching down and stowing it by hand.

 

[jb747]

Speed brakes, spoilers, and ground spoilers.

If you're sitting in the aircraft, and looking at the wing, these are a series of panels that rise at various points in the flight. They're mechanically more or less identical, but their behaviour isn't.

Speed brakes are a symmetrical extension of most (but not all) of the panels. The degree of extension is controlled by a handle in the coughpit. They are used to increase drag, an to either slow down, or to increase the rate of descent.

Spoilers are used for roll control. Extension is asymmetric Their activity in this mode is controlled by the pilots or autopilot's roll input.

Ground spoilers are the full extension of all of the panels. This happens automatically, 1-2 seconds after weight on the main gear, and with thrust levers at idle. Extension is controlled to limit any pitch up caused by the lift change. They spoil the wings' lift, and put weight on to the wheels.

 

[harvyk]

Interesting procedural difference.

Would that be a QF vs VA thing or an A380 vs B737 thing?

 

[Quickstatus]

From my days teaching people to fly...what is directly in front of you, you might be able to reach. Behind you doesn't

That was the initial criticism of the Hudson River pilots - that they ignored the possibility of turning around and go back. Is Going back-itis a strong psychological lure?

 

[jb747]

Would that be a QF vs VA thing or an A380 vs B737 thing?

Mostly Airbus vs Boeing.

There was a wonderful time in aviation, back around 1990-2000, when very little was said in the coughpit. Comments were due if things didn't happen, but little was said otherwise. Slowly but surely, calls, checks, checks on checks have crept in, until it's a constant stream of pointless procedural calls.

 

[jb747]

That was the initial criticism of the Hudson River pilots - that they ignored the possibility of turning around and go back.

I doubt that any actual pilots were even slightly critical of the crew. Armchair experts perhaps, but they don't have to make life or death decisions, in a few seconds, with only partial information.

The flying part of this incident should have been within the capability of pretty well any airline pilot. The really important part, and what made all of the difference, was that the Captain made the decision to go for the river. I expect many others wouldn't. Most would have died. Perhaps a couple would have gotten away with it. The river had the best chance of a good outcome. The actual result was probably better than anyone could have hoped for.

Is Going back-itis a strong psychological lure?

I expect that it's hard to decide to throw the aircraft away. And you always land at airfields, so anything else is totally against the flow.

 

[Major]

AV, is there a need for VA to provide any special training for the new BNE runway ?

Checklist: Are you runway ready? - Brisbane Airport

Construction on Brisbane’s new runway is fast approaching completion but before it opens in mid-2020 there is a 700 (and counting) point checklist of safety checks, training exercises and operational run-throughs to be crossed off the list by a whole bunch of agencies. While our list feels as...

www.bne.com.au

 

[AviatorInsight]

AV, is there a need for VA to provide any special training for the new BNE runway ?

Checklist: Are you runway ready? - Brisbane Airport

Construction on Brisbane’s new runway is fast approaching completion but before it opens in mid-2020 there is a 700 (and counting) point checklist of safety checks, training exercises and operational run-throughs to be crossed off the list by a whole bunch of agencies. While our list feels as...

www.bne.com.au

Not really. Airservices have put out a few bulletins that VA has all made us aware of. But there’s nothing new that’ll really trip up Pilots. A lot of the changes have already been made on the eastern side in preparation. The change of 2 ground frequencies now, rapid exit taxiway closures, the renaming to 01R/19L, and the installation of stop bar lights at each holding point (Soon to be commissioned). Even with the parallel runways it’ll work more efficiently than SYD with STARS joining onto the ILS.

 

[Mrmaxwell]

During my last overnight flight I woke early to see an amazing full moon setting beneath the clouds. It got me thinking pilots must get too see some amazing acts from Mother Nature....please do tell

 

[jb747]

During my last overnight flight I woke early to see an amazing full moon setting beneath the clouds. It got me thinking pilots must get too see some amazing acts from Mother Nature....please do tell

Mostly we’re turning away from, and trying to avoid, Mother Nature at her best.

You do see some staggering lightning storms. I’ve also seen sprites, but only ever once. I recall heading east over Oz, with the sun setting behind us. The cloud layer that we were above was dark, but the sun was able to illuminate the cloud from below, so the effect was like flying over a sea of lava.

Mt St Helens.

Passing over Sri Lanka, and having city lights, moon, and thunderstorm all in the one window simultaneously. I might even have a picture of that, but it doesn’t do it justice.

Mostly though, you have a sky full of stars to look at. An amazing number of pilots never look, but from 35,000’, even through armoured glass, it’s a wonderful sight.

 

[Quickstatus]

Meteors?