Ask The Pilot

[Quickstatus]

I hear on the www that some pilots got pinged for placing coffee on the controls

Which invites the question:
How many cup holders are there on a flight deck?

I understand this is a 737. What are the grey levers the cup is resting on?

 

[justinbrett]

I hear on the www that some pilots got pinged for placing coffee on the controls

Which invites the question:
How many cup holders are there on a flight deck?

I understand this is a 737. What are the grey levers the cup is resting on?


View attachment 319620

Surely that pic is a joke.

The levers are the fuel cut off levers. Pull them down and it stops fuel going to the engine, and thus, shuts down the engine.

It doesn't seem like a good idea to rest a coffee on them

 

[RooFlyer]

What's the flight state of the other controls in view?

 

[justinbrett]

What's the flight state of the other controls in view?

All indicate they are at cruise FL370 (37,000 FT), about an hour from top of descent.

Sadly doesn't look like a joke.

 

[Quickstatus]

Surely that pic is a joke.

Unfortunately no.

How many cup holders are there on aircraft flight decks?

 

[justinbrett]

Unfortunately no.

How many cup holders are there on aircraft flight decks?

At least 4 easily accessible to the CAPT/FO (total 6)- you can see the top of a water bottle in the pic above

Edit - this is for a 737NG, which is the aircraft in the SpiceJet pic, and the youtube clip above.

 

[RooFlyer]

Sadly doesn't look like a joke.

No: SpiceJet Pilot's Picture Goes Viral For All The Wrong Reasons

 

[AviatorInsight]

AV, do you reference third party flight tracking flights like FR24, or one of the others, while on shift for any useful means? I was sitting up front on a Rex flight recently and I noted the pilot checking FR24 and OzRunways before we departed, I assume checking for any unverified traffic in the local area?

Yep absolutely. I love FR24. I use it to find my inbound aircraft, and if I’m changing aircraft, when it is going out again so I know whether to shut down, or expect to hand it over to the next crew.

I also use it for aircraft tracking of other flights in the area. If there’s a long queue for example, I’ll bring it up to see how many other flights are also going to the same destination. This will give me a good indication if it’s worth speeding up, changing levels, expecting and holding enroute, etc.

I don’t use OzRunways. There are quite a number of captains that use it, and I see how beneficial it can be especially with the map overlays, but I’m quite happy with the Jeppesen app for now.

 

[AviatorInsight]

I hear on the www that some pilots got pinged for placing coffee on the controls

Which invites the question:
How many cup holders are there on a flight deck?

I understand this is a 737. What are the grey levers the cup is resting on?

I don’t know what’s dumber, the fact that these guys thought it was a good idea, or the fact that they decided to do it and take a photo, and post it online!

They are resting on the engine start levers. They are what introduces the fuel during engine start. To shut down the engine you need to take the lever and pull it out of the detent and slide it down into the cutoff detent. This will shut the engine down.

 

[jb747]

My wife used to track all of my flights with FR24. I used it for interesting events, and tracking the aircraft I was waiting for in Dubai. Never heard of Ozrunways, but the Jeppesen worked for what I needed.

Even having your hand near the start levers would make me nervous. The cup of coffee is simply crazy.

 

[OZDUCK]

My wife used to track all of my flights with FR24. I used it for interesting events, and tracking the aircraft I was waiting for in Dubai. Never heard of Ozrunways, but the Jeppesen worked for what I needed.

Even having your hand near the start levers would make me nervous. The cup of coffee is simply crazy.

And of course a spilled cup of coffee 'killed' Rod Taylor and everyone else, except for Suzanne Pleshette, on the plane he was piloting in the 1964 film "Fate is the Hunter".

Fate Is the Hunter (film) - Wikipedia

en.wikipedia.org

 

[RailFlyer]

In the "coffee" photo why are the #1 and #2 engine thrust levers not perfectly aligned? Does the AutoThrottle set non-symmetrical thrust in cruise to compensate for other factors or is it just a fit and finish thing that they don't align perfectly?

 

[jb747]

In the "coffee" photo why are the #1 and #2 engine thrust levers not perfectly aligned? Does the AutoThrottle set non-symmetrical thrust in cruise to compensate for other factors or is it just a fit and finish thing that they don't align perfectly?

This is known as thrust lever stagger, and can be a PITA in some aircraft. In most new aircraft the engines have fully digital engine control, but in older ones there can be substantial mechanical linkage between the levers and the engine control system. No two engines are ever exactly the same. So, you have the difference between the engines, and various amounts of slop (for want of a better word) leading to different thrust lever positions for the same power setting.

You also need to realise that an autothrottle moves the thrust levers, but does not itself control the engine power. When the autothrottle wants say, TO/GA, it advances the levers until one engine hits the limit (or target power setting), and then it stops. One of the pilots will then push the lower engine‘s lever forward to match the power. Matching the power up used to be the domain of the flight engineers. On the 767 (other than OGV) up to 30 mm difference between the lever position at the same power setting, was common.

OGV (QF’s last new 767) was different because it had FADEC, a fully digital engine control. It was on all of the 747-400s but not the concurrent 767s. With that system engines would basically talk to each other, and the thrust lever system, and so remained matched as long as the levers were at least in proximity to each other. If you pulled one lever on a 747-400 back about an inch (in the cruise), the engine would initially roll back a bit, and the others would roll up to balance the total power. Then it would decide you were an idiot, and match all of the power settings, leaving that one lever an inch out of alignment. But, if you moved it a bit more it would fall out of the range, and the system would decide you might know what you were doing, and simply follow the throttle. In the 747-400, the engine levers were being moved by the system to match the power being demanded by the FADEC.

Airbus takes this a step further by decoupling thrust lever position with the power for 99% of the time, with the levers simply sitting at various gates, irrespective of the engines’ power settings. One extreme case comes up in alpha protection, in which the thrust levers could be at idle, with the autothrust disengaged, and yet the engines will automatically roll up to TO/GA whilst the levers still sit at the idle position (if it detects an extreme angle of attack, i.e. stall).

There are other differences between various implementations of FADEC. For example on the 747-400 as you rolled on to the runway, and selected your takeoff power, you could literally slam the levers forward, and the thrust would remain symmetrical. The FADECs would ensure that the slowest engine to spool up controlled all of their accelerations, and so ensure the power was symmetrical. The otherwise very automatic 380 did not do this, and quite a bit of care had to be exercised with the initial spool up on the runway (below about 70%), as the engines could spool up at very different rates and lots of differential power at low speeds can cause severe directional control issues. This effect could be made worse if you’d been using differential power to help in the turns on the taxiway, as the engines seemed to have a memory, and engines that had most recently been pushed up a bit, also tended to accelerate quicker when on the runway.

 

[RailFlyer]

This is known as thrust lever stagger, and can be a PITA in some aircraft. In most new aircraft the engines have fully digital engine control, but in older ones there can be substantial mechanical linkage between the levers and the engine control system. No two engines are ever exactly the same. So, you have the difference between the engines, and various amounts of slop (for want of a better word) leading to different thrust lever positions for the same power setting.

You also need to realise that an autothrottle moves the thrust levers, but does not itself control the engine power. When the autothrottle wants say, TO/GA, it advances the levers until one engine hits the limit (or target power setting), and then it stops. One of the pilots will then push the lower engine‘s lever forward to match the power. Matching the power up used to be the domain of the flight engineers. On the 767 (other than OGV) up to 30 mm difference between the lever position at the same power setting, was common.

OGV (QF’s last new 767) was different because it had FADEC, a fully digital engine control. It was on all of the 747-400s but not the concurrent 767s. With that system engines would basically talk to each other, and the thrust lever system, and so remained matched as long as the levers were at least in proximity to each other. If you pulled one lever on a 747-400 back about an inch (in the cruise), the engine would initially roll back a bit, and the others would roll up to balance the total power. Then it would decide you were an idiot, and match all of the power settings, leaving that one lever an inch out of alignment. But, if you moved it a bit more it would fall out of the range, and the system would decide you might know what you were doing, and simply follow the throttle. In the 747-400, the engine levers were being moved by the system to match the power being demanded by the FADEC.

Airbus takes this a step further by decoupling thrust lever position with the power for 99% of the time, with the levers simply sitting at various gates, irrespective of the engines’ power settings. One extreme case comes up in alpha protection, in which the thrust levers could be at idle, with the autothrust disengaged, and yet the engines will automatically roll up to TO/GA whilst the levers still sit at the idle position (if it detects an extreme angle of attack, i.e. stall).

There are other differences between various implementations of FADEC. For example on the 747-400 as you rolled on to the runway, and selected your takeoff power, you could literally slam the levers forward, and the thrust would remain symmetrical. The FADECs would ensure that the slowest engine to spool up controlled all of their accelerations, and so ensure the power was symmetrical. The otherwise very automatic 380 did not do this, and quite a bit of care had to be exercised with the initial spool up on the runway (below about 70%), as the engines could spool up at very different rates and lots of differential power at low speeds can cause severe directional control issues.

A very comprehensive and interesting reply. Thanks.
So in the photo, the levers will have been moved together by the AT and then a pilot will have increased the left one manually a bit so their power output matched? What happens when the AT decides another change in power is required, do they move with the same stagger or go back to being in line? i.e. are the pilots of a 737 having to make small adjustment to one power lever after each AT change?

 

[jb747]

A very comprehensive and interesting reply. Thanks.
So in the photo, the levers will have been moved together by the AT and then a pilot will have increased the left one manually a bit so their power output matched? What happens when the AT decides another change in power is required, do they move with the same stagger or go back to being in line? i.e. are the pilots of a 737 having to make small adjustment to one power lever after each AT change?

The stagger will remain unless the autothrust system happens to demand ‘idle’ in which case they’ll both end up aligned when it hits the stops. The pilots will match things up occasionally, but it’s not something you need to be doing constantly. It‘s important when limit settings are being demanded, but otherwise a slight difference doesn’t matter. The next question that then comes up is that if you’re going to match the engines in the cruise, what setting (EPR, RPM, fuel flow, temperature) do you choose to match?

Another issue with the 767 autothrottle (and I expect that the 737 is the same) is that the system would sometimes fail to grab one lever. So, for instance, at top of descent when it would command the levers to idle, one might get left where it was, or somewhere between that cruise setting and idle. It was possible in the other direction too. For that reason any time the autothrottle was making a major adjustment to the power you would always have your hand on the levers. It also meant that if you thought you’d done something (like pushing the TO/GA switches) but hadn’t, then you were already in a position to simply push the levers to the spot you wanted, without delay. Still on Boeing, but if you pushed the levers to a position that the autothrottle didn’t want, it would initially try to pull them back against your hand. If you didn’t let it do so, it would transition to a mode called ‘thrust hold’, and leave the levers where you’d put them, until a mode change was called for. This was very useful during descents.

 

[jb747]

And of course a spilled cup of coffee 'killed' Rod Taylor and everyone else, except for Suzanne Pleshette, on the plane he was piloting in the 1964 film "Fate is the Hunter".

So in the end it was all Suzanne’s fault.

I looked at the IMDB summary of the story. One engine failed due bird strike, and then the pilot subsequently shut down the other after a fire warning. So, that leaves the question of whether you should shut down an engine with a warning light if you happen to actually need that engine. Even if really on fire, it’s almost certainly still producing power.

 

[RooFlyer]

Even if really on fire, it’s almost certainly still producing power.

Do you know if the engine manufacturers have tested the scenario of a actual on-fire engine is kept at some thrust level?

Might there be a chance that it might go bang in a very bad way if kept operating while on fire?

 

[justinbrett]

Never heard of Ozrunways

Designed by a RAAF pilot whilst still in uniform. I did a safety course with him once and he offered me a free subscription.

I think he's out now - he's done well for himself. He also owns the NAIPS app.

 

[jb747]

Do you know if the engine manufacturers have tested the scenario of a actual on-fire engine is kept at some thrust level?

Might there be a chance that it might go bang in a very bad way if kept operating while on fire?

Firstly the movie being discussed had the engine being shut down, and converting the aircraft into a glider based upon a FALSE fire warning. If it’s the last engine you have, you’d really want to be trying to confirm things before shutting down the only engine remaining.

As for the makers though, you’d definitely be in uncharted territory. But, the issue is always going to be whether the risk of a bang is worse than the 100% chance of being in a glider. If it was a confirmed fire, then it’s probably not your day, but you’d still keep trying to pick the best of the bad choices.

 

[Saab34]

Gents, in light of the Jetstar passenger thread incident, do Pilots talk to problem passengers in which situations? Does every captain take a different way of handling it? (Ie do some go down to sort it out, vs others who just don’t get involved)