[maddy42]

Is there a major difference between cargo planes and passenger? Asking as I saw a video of the Antonov landing in Perth and noticed stuff like winglets at the tip of the wings missing.

https://youtu.be/1qu_esv8EJ0

Opinion on this aircraft as it seems to be a soviet era design.

Thanks,
Maddy

[apachelongbow]

Originally Posted by Jeroen

Ok, here a detailled questions for the pro’s. Searchhaven at the beginning of this terrific post mentioned modes such as VNAV, V/S.

It is easily one of the most hotted discussed topic on many aviation forums. Which also suggest there might be one more correct answer. Just to add, lets have a go at FL CH as well.

I’m not sure how this works in an Airbus?

Airbus has a simplified view about all modes, unlike a Boeing. Airbus provides 3 modes in climb or descent, namely Open Climb/Descend, V/S, managed Climb/Descend. There is a version known as Flight path angle and flight path vector (FPA/FPV) which i will touch upon later.
In climb/open climb or descend/open descend modes, the airplane will follow fmgc instructions with/without speed/altitude restrictions to reach the particular altitude selected. Thrust modes are in either thrust climb (auto thrust maintaining climb thrust and autopilot maintains pitch for the speed), or in speed/thrust idle mode, where in auto thrust maintains speed and auto pilot maintains pitch or auto thrust is in idle and speed and pitch control are by auto pilot using elevators alone. Vertical speed mode is a speed mode and thrust is never idle unless the v/s selected is greater than what the selected speed can provide (say 210 kts and 2000fpm descend).
Any reverts from one mode to the other because of pilot input or otherwise is indicated by a triple click sound and particular mode flashing on the FMA.
FPA/FPV is a function of energy management, driven by ADIRS to ensure that you have sufficient energy to perform say a visual approach. There is a concept called a bird (Flight path Vector) which provides for even drift (track) to ensure that you are on the right track to say the runway.

[Jeroen]

Originally Posted by maddy42

Is there a major difference between cargo planes and passenger? Asking as I saw a video of the Antonov landing in Perth and noticed stuff like winglets at the tip of the wings missing.

Not really. This happens to be an old design and it was never updated with winglets. These days most jet airliners come standard equipped and a lot of older planes have been modified. Still, Plenty of old passenger jets flying around without winglets too.

This Antonov is actually quite an old plane. It's unique when it comes to size and payload. I don't think they worry too much about fuel efficiency.

My own impression of Russian aviation is that it is usually very high on practicality and robustness, but not so much on finesse. It's probably true for their military planes as well.

Jeroen

[chandrda]

Just Brilliant and Thank You very much for the review.

I have few basics questions -

1. In the early 2000s, the ground speed of the airplanes used to 950 to 1050 KMPH. Now its around 850 KMPH. I remember Bangalore to London was under 9 hours on good days, now its 10.5 hours. Is this because of 2 engines and economics of fuel

2. There are many reasons as why lights are dimmed while landing/take off, but what is the official reason?

3. How much does an aircraft stretch and twist under pressure while flying, as I see the wings completely bent upwards in flight.

4. Why is roll/pitch felt more in the tail of an aircraft

Regards

[Petrolhead007]

Aircrafts have always fascinated me, thank you for that wonderful review and insights into the 777.

I do watch a lot of Air Crash Investigations as these have fascinated me for years as to how the investigator arrives at what had gone wrong from the wreckage.

Knowing about TCAS (Traffic Collision Avoidance System) was an interesting piece for me. What other built-in safety measures are there in the flight that helps to keep the plane safe?

Also, since you are in this field, in case of an emergency landing in water, which is the right thing to do? Inflate after we get out of water and see some light or inflate it before the flight lands in water?

Apologies, I am asking questions that may not be appropriate, but I fly a lot and these things always bug me but still I enjoy flights.

Great review once again. Thanks for sharing.

[Jeroen]

Originally Posted by chandrda

1. In the early 2000s, the ground speed of the airplanes used to 950 to 1050 KMPH. Now its around 850 KMPH. I remember Bangalore to London was under 9 hours on good days, now its 10.5 hours. Is this because of 2 engines and economics of fuel

NOt sure compared to 2000, but certainly in the last couple of decades aircraft speed have come down a bit.

Planes such as Boeing 707, DC8 cruised some 10-25 knots faster than most of today's jets.

The reason is fuel consumption. Especially current high bypass jet engines have a narrow range at which they operate most effectively. Push them beyond and fuel efficiency drops quite a bit.

They reach their max efficiency at slightly lower speeds. Also, the lower speed affects the overall design. Less speed, means less wing sweep, which means less weight, which means cheaper to built.

Jeroen

[Jeroen]

Originally Posted by apachelongbow

There is a concept called a bird (Flight path Vector) which provides for even drift (track) to ensure that you are on the right track to say the runway.

Thanks. That sounds similar to Boeing Altitude Range Arc. It indicates where the MCP altitude will be captured based on current ground speed and vertical speed.

Or it this bird thing something different altogether?

Jeroen

[Gansan]

Originally Posted by searchingheaven

In litres, it would be equivalent to 181,283 litres.

That is at least ten tanker loads! Is all that fuel loaded inside the wings? They don't appear thick enough to accommodate such a load. How is that huge fuel load evenly distributed and consumed, without affecting the balance of the aircraft? Is there some kind of ballast arrangement?

And while coming in to land, at least in fair weather conditions, will the engines be producing thrust or somewhat in idle?

[RVD]

Originally Posted by Jeroen

Thanks. That sounds similar to Boeing Altitude Range Arc. It indicates where the MCP altitude will be captured based on current ground speed and vertical speed.

Or it this bird thing something different altogether?

Jeroen

Its completely different. Boeing also has the Flight Path Vector(FPV) in addition to the altitude range arc. The former giving you the real time drift and flight path angle information on the PFD. It is very handy tool when doing Raw Data flying. It gives the aircraft's flight path angle with respect to the Horizon irrespective of the pitch attitude. It derives is data mainly from the inertial system. Although Boeing also advises against its use in case of a faulty air data system component. The altitude Range arc on the other hand ( As you pointed out) gives an range at which the selected altitude will be captured. It is an instantaneous value hence you will notice that the arc keeps shifting during a climb or descent in response to various parameters. It does not take any performance criteria under consideration. For Eg, in a climb it may show the altitude capture at a certain distance but as the performance of the aircraft degrades as the aircraft climbs, the arc will keep moving further aft.
Attaching a picture of FPV. May help you understand it better.

[searchingheaven]

Originally Posted by Gansan

That is at least ten tanker loads! Is all that fuel loaded inside the wings? They don't appear thick enough to accommodate such a load. How is that huge fuel load evenly distributed and consumed, without affecting the balance of the aircraft? Is there some kind of ballast arrangement?

And while coming in to land, at least in fair weather conditions, will the engines be producing thrust or somewhat in idle?

Yes, the wings and the fuselage store the fuel.

This image is from the MFD(multi function display) of the 777-300ER. It shows the total amount of fuel as 102,000 kgs. Green rectangles are the fuel pumps, total of 6, 2 for each tank. Normally, the center tanks are emptied first and then wing tanks are used. Also, notice the cross feed valves. Generally, the Left fuel pumps supply fuel to left engine & vice versa. The crossfeed valve is used to temporarily connect the two sides of the system. This system allows the shortest route for the fuel and keeps the systems separate, so a leak on one side cannot drain the entire system. The crossfeed valve is generally kept shut for this reason. A || double line indicates a closed valve while a single line indicates a open valve.



The thrust while landing depends on a LOT of factors. Your Vref i.e landing speed, flaps settings, winds etc. The idea is to maintain a set speed, and not set thrust.

Originally Posted by Petrolhead007

What other built-in safety measures are there in the flight that helps to keep the plane safe?

Also, since you are in this field, in case of an emergency landing in water, which is the right thing to do? Inflate after we get out of water and see some light or inflate it before the flight lands in water?

Thank you for the compliments.

There are so many safety features present in the 777 or any modern aircraft that it will not be possible to list all of them here. Although, they are primarily divided into two categories. The first one prevents any untoward situation from occurring in the first place. for eg. stall protection, which will not let the aircraft stall. The second category comes into play when such a situation has occurred for eg. the ditching button in the Airbus, which closes the valves and openings underneath the aircraft, including the outflow valve, the air inlet for the emergency RAT, the avionics inlet, the extract valve, and the flow control valve.

As far as a water landing is concerned, it is IMPERATIVE that you inflate the jacket ONLY after leaving the aircraft. This is due to the fact a life jacket is designed to float. If you have inflated the jacket before leaving, as the cabin floods, you will pushed upward against the ceiling; making it impossible to dive and reach the exits, leaving you trapped inside the sinking fuselage.

If fact, this is what happened to the Ethiopian 961.

Originally Posted by chandrda

2. There are many reasons as why lights are dimmed while landing/take off, but what is the official reason?

3. How much does an aircraft stretch and twist under pressure while flying, as I see the wings completely bent upwards in flight.

4. Why is roll/pitch felt more in the tail of an aircraft

Regards

2. Already discussed. Please refer my earlier post. Link to post

3. For the 777, it's like 15 feet or less.

4. That is a misconception. An aircraft is like a see-saw, with the center of gravity being in the wing area. The fulcrum is near the wings. So the pitch is felt most at the rear and the front. But the thing is, while climbing the aircraft pitches up so the rear goes down considerably. But descent does not command a pitch angle like climb does. So at the rear, you might not feel that the aircraft is pitching down.

Thanks for the compliments.

Originally Posted by Jeroen

Thanks. That sounds similar to Boeing Altitude Range Arc. It indicates where the MCP altitude will be captured based on current ground speed and vertical speed. Or it this bird thing something different altogether?

No, the FPV is completely different. It is present in the 777 also. Check the EFIS control panel image in the first page which shows the FPV button. It's an icon displayed on the PFD which provides the flight path angle and drift. It tells us where the plane will be shortly if the flight controls and throttles aren't moved from their current position. It's based on inertial data calculated in the ADIRU and fed to the FMC.

Altitude range arc simply draws an arc on the ND showing the point at which the climb to the altitude set on MCP will be reached.

[maddy42]

Thanks Jereon, that was insightful. On a side note do check out this takeoff in a muddy airfield.

https://youtu.be/SnS-C_oyEd0

Thanks,
Maddy

[vinair]

Brilliant thread!! So many details and nuances its just wonderful to be reading all the stuff!!

Got a question and it always bugs me, not sure if I have already asked this on a different thread!

After push back, when taxiing (hope that's the right spelling!), is there some sort of a 'idle setting' for the engines to run just enough to move all the bulk of the aircraft on the ground?

Also, just before take off, does the plane only depend on the brakes to stay still while the engines are being pushed for max thrust?

[apachelongbow]

Originally Posted by Jeroen

Thanks. That sounds similar to Boeing Altitude Range Arc. It indicates where the MCP altitude will be captured based on current ground speed and vertical speed.

Or it this bird thing something different altogether?

Jeroen

That sounds like the Airbus energy circle or arc. It will show the track miles needed to be at approach config speeds based on current airspeed, configuration and rate of descent. It's available only on heading mode.

[keroo1099]

Lovely thread.

Don't want to sound disrespectful but how do you keep your concentration levels up during long flights if you are really not 'flying' most of the time. It seems automation on commercial flights have made you redundant except for takeoffs, landings and emergencies.

For me the situation is similar to driving on long straight expressways because it reduces my focus and ultimately gives me less chance to react in time to an emergency.

[A350XWB]

Originally Posted by searchingheaven

GE90-115B
This monster of an engine delivers 115,300 lbf of thrust & powers the longer-range Boeing 777-200LR, 777-300ER and 777 Freighter aircraft.

Any specific reason to skip the mention of PW and RR engines?
Options for 777-200 - Pratt & Whitney PW4074, RR Trent 875, GE90-75B.
For the 247 tonne MTOW version - PW4077, GE90-76B, RR Trent 877.
For 777-200ER - PW4084, GE90-85B, RR Trent 884, PW4090s, GE90-90B1, RR Trent 890, GE90-92B.
For 777-200LR & 777F - GE90-110B1 or GE90-115B.

For 777-300 - Pratt & Whitney PW-4090, PW-4098, RR Trent 892,GE90-92B.
777-300ER - GE90-115B

On 772L, 777F and 773ER the GE-90 is the sole engine on offer due to the agreement between GE and Boeing because of the expensive engine development (the power rating requirements were beyond anything attempted till then). For the program to be profitable, GE wanted exclusive engine rights and in return, they agreed to be a risk sharing partner for the development of these variants.

Originally Posted by searchingheaven

Available in 5 variants, seating 301-368 people in a 3 class configuration.

Actually, it is (rather, was) available in 6 variants
777-200, 777-200ER, 777-200LR, 777F, 777-300 & 777-300ER.

Originally Posted by searchingheaven

Withstands turbulence better than the Airbus 330/340 because of rigid and sturdier wings.

I would be interested in some measurements or statistics for this. I keep searching and could not find any on-line.

Originally Posted by searchingheaven

But the Boeing 777-300ER and 200LR are now 20 years old and will have to be replaced by the 777X by 2020.

The first -200LR was delivered to Pakistan International Airlines on February 26, 2006. The first -300ER was delivered to Air France on April 29, 2004. That makes them 10 and 12 years old respectively and not 20.

Originally Posted by searchingheaven

For now, the A350-1000 is head-to-head with the 777-300ER, as the following picture shows. [Last line is cost/seat/mile]. The problem however is that the A350-1000 will be delivered by 2020, by which time the 777X will be here. Then, the A350-1000 will compete with the 777X and will find it very difficult to hold its own.

Ok, let's see the numbers in the table you have shared. The CASM values are
B777-300ER - 0.0745
A350-1000 - 0.0620
B777-9X - 0.0602

So the difference between 773ER & A350-1000 is 0.0125
The difference between A350-1000 & 777-9X is 0.0018

According to your post above, a difference of 0.0125 is head to head and a difference of 0.0018 will be difficult for the A350-1000 to hold its own. Can you explain this?