[djpeesh]

Originally Posted by RVD

I think you may be referring to ANA which still flies the sector on a 737 along with a 787. Even Ethiopian and Kenya airways operate 737 on the Mumbai route, again , along with their 787's.

RVD, as far as I know, NH943 (the 38 seat, all business 737 from NRT to BOM) has been replaced by a 787. I took a flight in March last year and I was told that the service was being replaced by a Dreamliner.

Off topic: I was expecting the flight to be really comfy as it was my first time flying an all-business class service. The seats were horrible although the service was top notch and the food was to die for.

Not sure if the 787 is all business or business and economy. I need to send a proposal to the boss for another week long Tokyo business trip.

[PetrolRider]

Originally Posted by Jeroen

In general, over the last couple of decades airspace has become busier and busier. Also vertical and lateral seperation is becoming smaller and smaller. So yes, it is not unusual to see several planes around you, heading in different directions and altitudes. (As a passenger you typically dont see the one that are behind or in front of you.)

Whether there will be contrails, and how long they are visible, is more down the temperatures and humidity plus a few other factors.

Jeroen

Thank you for this clarification. Yes, a simple google told me the factors behind the contrails .

Originally Posted by RVD

I think you may be referring to ANA which still flies the sector on a 737 along with a 787.

Originally Posted by akshay1234

Unrelated, but I remember that JAL used to fly a 737 on this sector in an all business class configuration if I'm not mistaken.

Yes it was ANA who operates 787 on BOM NRT sector.

Originally Posted by djpeesh

RVD, as far as I know, NH943 (the 38 seat, all business 737 from NRT to BOM) has been replaced by a 787. I took a flight in March last year and I was told that the service was being replaced by a Dreamliner.

Off topic: I was expecting the flight to be really comfy as it was my first time flying an all-business class service. The seats were horrible although the service was top notch and the food was to die for.

Not sure if the 787 is all business or business and economy. I need to send a proposal to the boss for another week long Tokyo business trip.

I have a different view here, for me, the 787 was definitely comfortable that the 767-300ER I flew on DEL NRT sector of ANA. And ANA and JAl alike, Japanese carriers provide super service. I even would rate them above Emirates.
The BOM NRT sector ANA 787 is of 3 class configuration, Economy, Premium Economy and Business.

[RVD]

Originally Posted by djpeesh

RVD, as far as I know, NH943 (the 38 seat, all business 737 from NRT to BOM) has been replaced by a 787. I took a flight in March last year and I was told that the service was being replaced by a Dreamliner.

Off topic: I was expecting the flight to be really comfy as it was my first time flying an all-business class service. The seats were horrible although the service was top notch and the food was to die for.

Not sure if the 787 is all business or business and economy. I need to send a proposal to the boss for another week long Tokyo business trip.

I dont think that the 787's have replaced the 737's. I keep seeing both of them very regularly. I saw a ANA 737 in Mumbai just a few weeks back.

[McLaren Rulez]

Came across this video today. What a machine!!!

https://youtu.be/CwxGDdsI_bU

[honeybee]

https://youtu.be/5avi26t8Xpo

The wings have flaps on the forward side, protruding or extended as the plane approaches. They fold up under the wings just as the engines reverse the thrust. What are these flaps?

[RohanDheman]

Originally Posted by honeybee

What are these flaps?

These are known as leading edge slats which when deployed aid in creating more lift and also allow the aircraft to fly slower while landing.

[Jeroen]

Originally Posted by RohanDheman

These are known as leading edge slats which when deployed aid in creating more lift and also allow the aircraft to fly slower while landing.

To add: Technically, or more aerodynamically, speaking, slats allow the wing to operate under a higher angle of attack. That produces more lifts and that allows to fly the aircraft slower.

Simply put; higher angle of attack means the nose of the aircraft higher up to the horizon.

Jeroen

[audioholic]

Can someone please explain how this incident happened?

http://avherald.com/h?article=49ae8a9c&opt=0

British Airways B773 at London on Jul 7th 2016, 12 hours flight covers 0nm

A British Airways Boeing 777-300, performing flight BA-7 from London Heathrow,EN (UK) to Tokyo Haneda (Japan), had initially tracked on a northnortheasterly heading through Norway on a near polar track, but then turned east, flew a hold pattern over Finland and then tracked a significantly more southerly track than obviously planned. The aircraft thus was enroute at FL350 about 100nm southwest of Igarka (Russia) 6:03 hours into the flight when the crew turned the aircraft around, descended to FL340 and returned to London for a safe landing at Heathrow's runway 27R 11:45 hours after departure.

The caption was surprising, but the description was too confusing to me as a noob. From what I could infer, they lost the way. But shouldnt this have been realised much earlier or is there something that cant be realised until they passed over a town which they did not intend to? And why didnt they correct their route, and fly back six hours to reach the source?

[Turbanator]

Can someone please explain how this incident happened?

They must have been low on fuel to complete intended journey after this flight path fiasco

One of probable situation -

No commercial jet enters Russian airspace without clearance. An amended flight plan was obviously followed by the crew, starting with the eastward turn over Norway. That hold over Finland likely was because Russia was slow to provide the necessary clearances. The reason they decided to turn around can be many - winds on the more southerly track could have eaten into the fuel reserve, they may had initially hoped to get clearances for their amended flight plan in the crowded airspace over Japan, but then couldn't, etc.
It looks like dispatch gambled that they could fix their clerical error, but later found they couldn't. None of this makes no sense.

http://avherald.com/h?article=49ae8a9c

[Jeroen]

This is just incredible, have a look at this paper Air India 777 model

https://www.flickr.com/photos/lucaia...7632208677161/

[audioholic]

Originally Posted by Jeroen

This is just incredible, have a look at this paper Air India 777 model

https://www.flickr.com/photos/lucaia...7632208677161/

And if you see the time lapse video of this build in progress, you will be mindblown by the kind of finesse that this great man puts into the whole design. The cargo door, thrust reversers and gear are some of the most detailed designs. Not sure what would be the best words to appreciate his art.

https://www.youtube.com/watch?v=1LckG_P135Q

[no1lives4ever]

Originally Posted by Jeroen

This is just incredible, have a look at this paper Air India 777 model

https://www.flickr.com/photos/lucaia...7632208677161/

Originally Posted by audioholic

And if you see the time lapse video of this build in progress, you will be mindblown by the kind of finesse that this great man puts into the whole design. The cargo door, thrust reversers and gear are some of the most detailed designs. Not sure what would be the best words to appreciate his art.

Check the other albums by Luca Iaconi-Stewart.

https://www.flickr.com/photos/lucaiaconistewart/albums

He has a wikipedia page which does not give much more information.

https://en.wikipedia.org/wiki/Luca_Iaconi-Stewart

Getting back to topic.

In March this year I took a BOM-DEL AI flight that was run on a 777-300ER. We ended up taking a bus from T2's domestic area to the international side and boarding the aircraft from the starboard side. This is the only time when I have boarded a jetliner from the starboard side and not from the usual port (left) side. I wonder if this is a regular AI service or if it was a one off service to ferry the aircraft.

-- no1lives4ever

[im_srini]

Awesome thread Intentional or not, this thread started out very specific to the 777 & has now become the "go-to" thread for anything aeronautical.

In any case, just came across this cool video demo-ing thrust reverser operation on the CFM-56.

https://www.youtube.com/watch?v=Npd5F80FNXA

Surprising thing is that it appears that only the bypass airflow is "reversed", at least from what's shown in the video.

So, the airflow through the core ( gas-producer section ? ) would still generate thrust in the forward direction isn't it ?

When the switch is made from reverse-idle to full-reverse, the thrust from the core & the thrust from the bypass airflow oppose each other ( ? ).

Given the level of deceleration usually seen when the reversers come on, the bypass airflow must be contributing a significant percentage of the total thrust, isn't it ?

It's surprising these fans generate so much thrust, given that there's just the one fan.

What RPMs do these fans rotate at ? The internet says 2,500 to 3,000 RPM, is this correct ?
.

[Jeroen]

Originally Posted by im_srini

Surprising thing is that it appears that only the bypass airflow is "reversed", at least from what's shown in the video.

So, the airflow through the core ( gas-producer section ? ) would still generate thrust in the forward direction isn't it ?

When the switch is made from reverse-idle to full-reverse, the thrust from the core & the thrust from the bypass airflow oppose each other ( ? ).
.

Yes, the air through the core does still generate thrust. However, the vast majority of the thrust is generated by the bypass airflow and it is only that part that gets reversed.

How much thrust is generated by the bypass air flow versus core differs depending a lot on engine design and it also depends on parameters such as altitude. But as a very rough rule of thumb for commercial by pass jet engines it could be in the 60-80% ratio.

The actual bypass ratio varies a lot too, but again, rule of thumb for the typical wide bodies, somewhere in the 1:8 - 1:10 ratio

Note that bypass engines are nothing new. They have been around since the 1950’s and also military fighters make use of them albeit usually at a much lower bypass ratio.

Have a look:

https://img-new.cgtrader.com/items/2...4395404a76.JPG


Have a look around the GE website. Lots of interesting stuff!

http://www.geaviation.com/commercial/engines/ge9x/

Originally Posted by im_srini

Given the level of deceleration usually seen when the reversers come on, the bypass airflow must be contributing a significant percentage of the total thrust, isn't it ?
.

See above. Note that in most landings it is the brakes that ensure deceleration! The thrust reversers are there for the brakes to do less.

Most commercial jet liners and certainly all wide bodies have a so called auto-brake system. Essentially it will ensure a constant rate of deceleration upon touch down. The pilots as part of their landing preparation will determine what setting they use (i.e. what level of deceleration), based on parameters such as landing weight and available runway length.

Upon touch down the auto brake system automatically applies the brakes.(I believe on the 777 it’s the nose gear strut compressing that activates the auto brake system).

It does so in a very clever fashion so it brakes at a constant rate of deceleration. At the same time the pilots will deploy the reversers. Which means that the brakes don’t need to be applied fully and thus is saves on brake wear. But it’s the brake system that sets the deceleration rate, not the thrust reversers.

The auto-brake system is also used (armed) during take off. Simply put, if the pilots close down the throttles (move to idle) during the take-off, it is seen as a RTO (Rejected Take Off) and the auto-brake applies maximum braking power immediately.

Enjoy, Jeroen

[honeybee]

Originally Posted by im_srini

What RPMs do these fans rotate at ? The internet says 2,500 to 3,000 RPM, is this correct ?
.

That seems to be correct, and a bit surprising - considering even a car's engine does about 6k rpms without sweat. I was under the impression these turbine engines could and would do about 30k rpms.

But the blades are massive, so I guess that low RPM figure is still good enough to power the plane. Some physics voodoo I don'tunderstand.