Yeah, I think the ADS is related/similar to the Required Navigation Performance (RNP) I was discussing above....

http://en.wikipedia.org/wiki/Require...on_performance
http://en.wikipedia.org/wiki/Automat..._ADS-A.2FADS-C

I have no special insight on this. In my previous life, I worked as a programmer for a company called The MITRE Corporation, which does a lot of work for the Air Force and FAA. I was on a project called AERA (Automated En Route ATC) and I was developing algorithms to predict conflicts along the flight paths of IFR traffic. Last I checked (about 15 years after leaving MITRE), that program was still going strong but nothing had been fielded.

The FAA has spent untold millions (billions perhaps) on ATC modernization. I remember there was a huge IBM contract that ultimately went nowhere, and other large corporations have burned up lots of money with no results.

On the other hand, there have been advances on the communications side. You are right about the problem with congested radio frequencies, particularly with approach control facilities around busy airports. Throw in some weather with pilots all requesting deviations to their flight path, and you start getting lots of simultaneous transmissions which results in high pitched squeals on the frequency. This means that calls are being missed and that's a real safety concern.

Now we are seeing datalink communications directly to the airplane, mainly for international routes over the ocean. CPDLC (Controller-Pilot Data Link Communications) provides a means for receiving and acknowledging clearances via text.

I haven't used ADS-B, but as I understand it this system allows aircraft to broadcast their position, speed, heading, etc, to be used by any other participating entity. Thus, if I have this capability, I can form my own "radar picture" of the area, showing other aircraft. ATC can also use this information to show traffic in areas that have no radar coverage.

We have been training RNP (Required Navigation Performance) approaches in the sim for years now, but that's the only place I've flown them. Quito, Ecuador is the one I've seen a lot in training and it's in use down there, but we don't fly that trip out of New York.

When using RNP, our dispatchers have to verify that we will have adequate GPS satellite coverage for the time we will be making the approach. That information will be included on our flight plan. We monitor our RNP value (shown in tenths of a mile) throughout the approach, as well as monitoring our vertical and lateral deviation from the path. If any of these fall outside the required parameters, we execute a missed approach.

As a lawyer who was supposed to become a programmer and whos greatest Christmas gift ever was a Commodore 64 computer and as someone who is fascinated by aviation, i am kind of envious of your present and previous life I used to mess with computer programs when I was 14 to 18 years old. I have been getting back to it as a hobby, learning Java and web programming. I still find it very interesting.

I do too. I dabbled in Java when it was still fairly new (mid-90s), but I haven't done any programming in over 10 years. I should get back to it too. I always enjoyed it.

Hey OP, thanks for doing this. Question for you, I'm going on a family vacation in 3 weeks with the wife and kids (aged 4 and 6) and we are flying Delta. It will be the first ever flight for both kids and they have a fascination with airplanes! Do you think I could ask the Captain or FO when we board if the kids could see the cockpit? If so, do you think they would be granted permission?

Chances are nearly 100% that you could do this. The only reason they might decline is if the flight is running late and a visit would make pushback late(r). On the larger planes (with roomier cockpits), the pilots will often let the kids sit in the pilot seat for a photo op. This gets a little tough on an MD-88 or DC-9.

If you want, PM me the date and flight number. Give me your kids' names and ages and I'll contact the crew and let them know that I have friends on the flight who would like to say hi.

W0X0F:

Awesome thread. I really appreciate the effort you put into your responses. Here's a few questions that I've been wondering about:

I know there are multiple carriers operating in what I would perceive to be volatile regions at airports like Baghdad or Benghazi. Are these routes a concern for the pilot? How comfortable would you feel flying into an airport like this? Are these pilots compensated more for these routes or is this just something that you get assigned? How comfortable would you be executing a spiral/corkscrew landing?

Thanks again for the awesome thread, it's been a really good read.

We sometimes fly these routes as military charter flights. I've never gotten one myself, but I'd jump at the chance. I've never heard any other pilots express concern.

The routes that do concern me are flights into areas with risk of malaria. I've flown into Ghana a few times before I was aware of how serious the risk really is. I've heard enough stories of pilots contracting malaria over there that I now avoid that particular destination.

No. We get our standard pay rate.

I believe what you're describing is a "combat approach," designed to minimize the time that the plane is exposed to small arms fire. We have no training for any such maneuver, but I'd be comfortable with it.

Woxof: What is ATC telling the flight crew when they say"you are cleared for the option"? Thx again.

"Cleared for the option" means any of:

• A full stop (land, and taxi off the runway)
• A touch-and-go (touch down on the runway and immediately take off)
• A stop-and-go (touch down and come to a stop on the runway, then add power and take off)
• A low approach (overfly the runway without actually touching down)

A controller clearing a pilot for the option is generally expecting to see a touch-and-go or a low approach, so it's good etiquette to say something when you want to do something else.

Hey Dave, I can't improve on sopoRific's response. He nailed it!

When I was working on my master's, my adviser and professor was working on this project - he's an expert on antennas and RF transmissions. One of the biggest problems was the size of the antenna array required to pick this up (often done at the airports, and sent to the plane rather than the plane picking it up) and the "drift" caused by the technology. It's still pretty new technology, and different from GPS (which is inherently weaker toward the poles).

I do see it rolling out, but it requires new hardware on each aircraft. If I recall, Alaska/Horizon fly only 737s. Changing hardware on a plane is not a simple thing - it requires an aircraft re-certification, and I believe a type-rating or some flight crew qualification.

An airline like Delta has a 1/2 dozen or so types (assuming commonality between say an A330, and 757/767, 737s, DC9/MD, etc) and 700+ aircraft, this is not an easy task.

Alaskan has a single type (737-400+) and only 131 planes. Easier for them to pull off, and probably more benefit.

CATIII ILS and autoland usually can make up for this in the lower 48.

As a pilot, do you ever have nightmares about crashing?

I don't think I ever have, which seems surprising now that I think of it. I've had a handful of dreams over the years about seeing another plane crash, which was very disturbing. I woke up feeling a deep sense of loss.

Thanks for the reply. I always have nightmares before I'm due to fly. I actually don't mind flying over land so much because I figure you can glide to an airport, but flying over water bothers me because you're hours from anything but ocean if there is a problem. I'll always try to book a plane with 4 engines for overseas travel. Any advice to assuage the worries?

I could cite the safety statistics and unbelievable reliability of today's engines, but this fear is a visceral thing. I had the same uneasiness myself, dating back to my first water crossing in a single engine plane (West Palm Beach to Freeport, Bahamas). Later, when I flew the J-32 turboprop, I wasn't crazy about flights to JFK where the controller would take us way out over the Atlantic before turning us toward the airport. When I made my first ocean crossings, I remember coasting out and being very aware of the fact that a couple of thousand miles of open ocean lay ahead.

Somewhere along the line I lost all concerns and now I feel as comfortable as if I'm home sacked out on the couch watching TV. There might be a small element of denial in there, but it's mainly a confidence in the demonstrated (and personally experienced) reliability of the machine.

This can't possibly be true, can it? What's the glide rate on a commercial airliner? I would think that if you lost power you'd be coming down fast and hard.

I'll leave the technical answer to the expert, but its not nearly as bad you'd think. There are a number of total power loss planes that have landed successfully. I think the coolest is http://en.wikipedia.org/wiki/Gimli_Glider although this one has an awesome ending too: http://en.wikipedia.org/wiki/TACA_Flight_110.

Common misconception. The glide ratio of airliners are greater than you might think. Look at this excerpt from the Wikipedia entry for Air Transat Flight 236, an Airbus 330 that lost both engines and glided to a landing at Lajes in the Azores.


This plane glided 65 nm to a successful landing from an altitude of 33,000 (5.4 nautical miles high). That's a glide ratio of 12 to 1.

Thanks for giving of your experience and knowledge ITT.

Do you have any opinion on the likelihood of the 911 hijackers being able to pull off what they did with that remarkable efficiency, given what we know of their training and what you know of safety/security protocols and general aviation?

For example, was locking cockpit doors something that was hardly ever done pre-911? As a pilot pre-911 would protocol or just common sense guide you to lock the cockpit doors if a possible hijacking situation was developing?

How difficult would it be, from an aviation standpoint, for the hijackers to navigate to and hit their targets? in particular the Pentagon? How much training would that take in your view and would that training need to be on commercial jets or would training on propeller planes easily translate?

Deuces,

Keep your conspiritarding out of this thread.

Thanks.

Don't make false accusations.

I don't conspiratard. I'm asking someone with technical and practical knowledge questions that a lot of people have about commercial aviation with respect to an important event. That is perfectly within the bounds of this thread. He obviously doesn't have to answer them and I'm not trying to influence his answers in any way. I want to know the opinion of an authority and I'm not trying to advance my own opinion which incidentally has nothing to do with conspiracy theories.

Your work in the 9/11 thread would disagree.

Things have changed significantly since 9/11, specifically the way we deal with disruptions on board during flight. Prior to 9/11 we had something called the Common Strategy, and it was taught to crews. One of the basic tenets of this strategy was to do anything possible to defuse the situation, including allowing access to the cockpit. No one had ever conceived of using the airplane as an airborne missile.

So, no, we didn't lock the cockpit door. Just the opposite in fact. We freely permitted access.

It would have been much harder in the days before GPS, but now anyone can be trained on the mechanics of manipulating the FMS and autopilot to arrive at a particular geographical point. So, assuming they have a lat/lon for the target, they could fly to it. Some basic airmanship would be required at that point to actually the put the plane on the target.

That's about all I've got to say about that.