WineCountryUA

you left out those who think they know.


and we appreciate your knowledge based responses. ^

planemechanic

True, true.


Thank you very much.

JC5280

That used to happen to me a lot on here, while I was an employee. People wold respond to my responses and posts telling me I was "wrong". Granted, I wasn't totally open about being an employee in my posts. I was part of the process, software change, or procedure from the source. But there sure are a lot of people on FT that think they know something because of their 8-10 flights a month, or because they "heard it from a flight attendant", or my favorite...because they read about it in the paper.

phkc070408

I wonder when they plan on completing the remaining 5 or 6 aircraft. Now that peak season is over, hopefully it will be soon so they can move onto the next fleet.

Singapore_Schwing

God help us all if the slimline seats were to happen. Given wifi isn't done a year later, I think power in economy on the 747s in 2014 (http://www.united.com/web/en-us/Cont...y/default.aspx) is a pipe dream unless they run one extension cord from business to one seat in coach and claim success because they only ever intended to start in 2014 and will be done in 2018 (or whenever the replacement for the 747 comes along).

Power to each seat would seem to be a much more involved process (especially if they don't want it to cut out when too many people use it like on the 777s).

lensman

Each seems to come with its own difficulties.

The satellite internet requires an external (plastic or carbon fiber) radome so they actually had to replace part of the external aluminum shell on the top of the 747. Here's an article on the satellite internet installs on UA planes.

Of course, replacing and re-pitching every seat on the plane also *seems* involved. In reality it is the wiring that is probably the most involved so maybe that's why they seem to do these things in two steps - one where they put the seats in and a later step where they add power - which probably means wiring the seat for power vs replacing the seat but I don't really know. Planemechanic or Joseconlscrew28, any thoughts?

I wonder if the 747 can generate enough electricity to power all the seats in coach?

wxguy

747-400 Nose #8474, on and working well! I'm posting this from about 90 minutes out of NRT enroute to SFO on UA838. Listening to streaming radio without a problem. $16.99 for the flight.

Worked well the entire flight. I'm impressed!

planemechanic

That is not correct. A reinforcing doubler is added to the 747 antenna location, but nothing was replaced.


Well, the devil is in the details of course. It all depends on how the system is designed. If the in-seat power mod is done during a heavy check the seats normally go to an outside supplier for rework, so the seat side of the work would just be added to their work scope. If it comes in only for the in-seat power mod the work would likely be done with the seats installed. The cabling from seat to seat already exists, but that is for IFE, so new cables would need to be installed. Bringing power to those cables is probably the most challenging part of the project, as the electrical power would come from the power panels located in the front of the forward cargo hold. That area is all open during heavy check, but would require additional open up on a stand alone check.

All of these questions are why the prototype airplane always takes a lot of extra time, then we see where we can save time and shorten the following visits significantly.

Singapore_Schwing

Thanks! Insightful as always.

lensman

Fascinating. What's this antenna location that they are reusing for the satellite radome? I just read the accompanying article and noticed that they said that on the 737s the radome actually mounts on top outside the aluminum skin of the fuselage and they just have to drill a hole for the wiring.

Does the satellite internet kit double as a GPS antenna?

Kacee

I was on N182UA yesterday (subbed aircraft SFO-HKG). The internet worked very well. Reasonably fast, no disconnects, was able to switch devices between Macbook and iPhone. $16.99 for the entire flight (except the two hour deadzone when you hit Chinese airspace). First time in seven 744 flights this year that it's worked as advertised.

WineCountryUA

certainty not a shared antenna, GPS and the sat internet link are vastly different frequencies.

planemechanic

They do not reuse an existing antenna location on the 747. It is installed behind the current Satcom antenna. It is dedicated to the GCS (Global Communication Suite) system.

lensman

So what does "A reinforcing doubler is added to the 747 antenna location" mean?

planemechanic

The fuselage skin is designed to withstand the flight loads expected during the operational life of the airplane. When you add a load, the antenna, you must increase the structure that carries that load. In this case they design an additional piece of aluminum skin that "doubles" the load path, thus increase the ability of the local structure to withstand the increased loads due to the added weight of the new antenna. They also add antenna mounts, internal stiffners and in many cases either change the type of fasteners holding the parts together (from rivets, commonly called "hole filling fasteners", to transition fit bolts). Of course the new structure and the old structure does not always fit together as designed, either due to previous repairs are the installation tolerances from when the airplane was originally built. In those cases we have to ask our engineering, or Boeing, or the designer of the new installation for a revised installation instructions.

So a doubler is basically an additional skin piece overlay-ed on top of the existing skin and attached per the modification drawings to support the new antenna.