AlaskaCoho

Thanks for the advice, hopefully I can walk the thin line well and keep answering questions. Inquiring minds want to know!

AlaskaCoho

Just to clean up a point here, I looked up the TERPS (Terminal Instrument Procedures, an FAA manual on how to build an approach) for RNP. The lowest minima that is allowed for an RNP .15 approach is 250 feet. A standard Cat I ILS is 200 feet.
So any minimum that is more than 250 feet above the touchdown height is that way because of an obstacle in the critical area around the runway approach end or immediate missed approach path. JNU RWY 26 RNP.15 minimums are 326. Runway is 26 feet MSL.

AlaskaCoho

What no questions? Sitting here in foggy XXX waitn for the crew van hopin for an easy day and Mt R to stay quite!

Duckouttahere

Thanks for posting here AlaskaCoho. As you can tell by the number of views, this is a popular thread.

There was some discussion on this board earlier about flights to Hawaii having to divert to SEA on the ANC-Hawaii routes. Can you enlighten us to what is all involved with flying over a large expanse of water? Navigation? Emergency options?

Thanks

brarrr

I'm a materials scientist/engineer, finishing a PhD at UW - my department produces undergrads and grads that end up at Boeing in large numbers. A lot of info flows back and forth because of that.. I was once told that the wing of a 737 can have a 12" fissure or even crack/hole in it and the plane will handle at or near optimum, and with no safety risk as internal wing supports are on 18" spacings. While I have no doubt that it would be immediately fixed upon noticing and so the occurrence is very low... do you have any experience or anecdotal evidence of such architectural failures?

tusphotog

You're hooked on FT. That didn't take long!

tony2x

Don't worry, I've got plenty queued up, this thread is solid gold! So to the simulator, I was thinking of doing a sim experience with BA at LHR when I go back there next and wondered just how realistic they are compared to the real aircraft. And I totally understand if you wouldn't want to answer this bit but have you ever had to fly a scenario that you had only previously practiced in a simulator?

ANC

ok,
Does AS ever cancel flights on purpose due to light loads to save expense where they have 2 light loads in a row and can easily put everybody on the next flight out? lol ya you dont have to answer that...I wouldnt want you to get fired

AlaskaCoho

Well thanks for the question. I think this site from Boeing will answer a lot of the ETOPS questions: http://www.boeing.com/commercial/aer...y/fo01txt.html

As for the Alaska specific questions let me see if I can take a stab at it.

ETOPS as you probably know stands for “Engines Turn or Passengers Swim”. I know I know Boeing has another less interesting acronym but who are they anyway?

Currently only a few of the 800s are ETOPS certified jets. Alaska only flies the Hawaii trips using the pilots in LAX and ANC bases. Some SEA guys are qualified by virtue of being instructors for the ANC and LAX guys. FAs come from all bases as I understand it. Each jet used for ETOPS must also be certified ETOPS. This is a very costly undertaking for the airline as all MX issues are securitized on the jet even when they occur when the jet is being used on regular flights. Each jet used and certified must have been in use for a specified period of time and MX must have been squeaky clean for over a year before it is used overwater.

Since the flight to Hawaii is generally SW for all the west coast airports, all west coast airports may be used as alternates. Fuel requirements dictate that and ETOPS operation be able to always have fuel at any point in the flight to either make the destination with reserve fuel left over or be able to make an alternate with reserve left over. So a good deal of the time in the cockpit is spent calculating present position and fuel to the nearest slab of concrete. This is done so that at any moment the pilots are aware of what the plan will be if something goes wrong. The jets are able to fly the entire trip on one engine. This is part of which jets are certified for ETOPS. So fuel requirements and reserve must be maintained even if one engine goes on strike.

Navigation is accomplished using GPS/INS/computers to calculate the great circle (Aviation term) route from RNAV waypoint to the next RNAV waypoint. Aviation organizations have mapped out grids over all the earth’s oceans and named waypoints at even and odd whole number Lat/Long. positions. When a flight is cleared into what we call the “Oceananic” (aviation term maybe misspelled but you get the idea, hey I’m a pilot not an English major) they are cleared via waypoint to waypoint as direct as possible. These routes are named and used extensively by all civilian and military flights.

During the winter the jet stream can point directly at Alaska for a good portion of the season. With winds approaching 100kts on the nose, slowing the aircraft down it can take much longer for the ANC-Hawaii flight. ETOPS requires the flight to be able to make the trip plus have a pretty extensive reserve of fuel left over. When they do the flight planning, if they don't have enough fuel for the trip plus reserve than they have to either not fly or look for another way to satisfy the FAR fuel requirements. What Alaska has been doing is fly to SEA or PDX, pick up another full load of fuel and approach the wind from another angle and of course a lesser distance thereby satisfying the fuel and reserve requirements. I'm not sure what the wind speed cutoff is for having to make the extra stop.

Flying terminology Alert!: This extra stop is called a "flag stop".

Hope this helps!

AlaskaCoho

I hate it when I don't have an answer. I called around to a few friends, yes even I have friends Jacksonflyer, and couldn't come up with any references for you. One buddy at Boeing says that your reference to 18" spacing may have to do with the failure test done on the jets as they exit the design phase.

When Boeing builds a jet they always take the second jet off the assembly line and stress test it to the breaking point. They video this process in great detail and note where the cracks first occur. Using this data they are able to build an inspection profile for each jet as it ages. Boeing may have the photos and videos available through their safety office.

Sorry I couldn't be more help.

Duckouttahere

Thanks for your response. I've always enjoyed the fact that the Hawaiian Islands are so isolated and think it's pretty cool to see nothing but water for hours and then all of a sudden see the islands pop up ahead. It's amazing how the Polynesians were able to navigate back in the day.

Thanks again.

AlaskaCoho

I may have over 15K flying but I probably have at least an additional 2 or 3 K in simulators of all kinds. Beginning in the late 60s the AF began to use simulators with a visual presentation that was generated by a little camera moving over a miniature diorama. It was kinda fun but could be costly when you tried to fly thru the base commander’s house. Don't ask. Anyway the simulators have come a long way.

Current full motion simulators with full vision are so good that the FAA will certify pilots to fly all the current airliners in the sim. That’s right many many pilots first flight in a jet is with passengers on it. The feel and motion and visual presentation are so good that when I get out of my annual checkride I’m usually covered with perspiration! I know we never sweat, we’re professionals, but when you have professionals checking other professionals its big boy play day. It can get ugly. I have on many occasions dead sticked in a 737, after of course the training or check ride objectives are met. The point here isn’t that it is all work or that it is all fun. We train like we fly and we fly like we train. We all met the same training standard, no breaks are cut for anyone. We practice even the most remote possibility in the sim so that if it happens on the line we have seen it at least once before. Occasionally things happen on the line that no one anticipated. Part of the safety program at all airlines is to then incorporate this event into the sim so that other can learn and benefit from the event.

As far a practicing a real word event, yes on more than one occasion and in more than one jet.

AlaskaCoho

Humm, I know it seems like they do and even we pilots get the impression that this goes on from time to time. However we are assured very adamantly from the powers to be that this does not happen and can not happen. It is against the law. When an airline is allowed to operate a “Scheduled” as opposed to non-scheduled airline they are certified to do so. Part of accepting the certification is a written set of rules. One of those rules is a specific prohibition from canceling flights based on a lack of interest.

That’s what I’m told anyway. Now are there ways to get around this rule? I don't know I just fly'em.

brarrr

A little extra - great circle is not solely of the aviation domain, but refers to the issue involved w/ projecting between 2D and 3D sphere surfaces. A way to think about it is if you were at the center of the earth and you could see through the surface to a 2D plane beyond the surface, you could follow a pth on the surface and trace it on the 2D plane... but then look at the 2D plane on its own and what, from the center of the earth was once straight, now appears curved. Errrrr that's not very clear..

Some info here: http://en.wikipedia.org/wiki/Great_circle

And if you want to map out your usual flight routes via a great circle, this is a good site: http://gc.kls2.com/

AlaskaCoho

Yeah and us unedjamacated pilots just say the shortest distance beteen two points is curved. LOL