Saturday, February 07, 2009

US Airways 1549 Audio

The audio and transcripts of radio and phone communications by air traffic controllers while the US Airways flight was ditching in the Hudson River last month have been released. I'm going to talk about them today and finish the trip to Texas tomorrow. To hear communications between the pilots and the departure controller, listen to the first one, the New York Tracon.

It's not too hard to understand, once you get past the New York accents. There are very few transmissions from US1549. Talking on the radio is low priority and low priority tasks drop out during an emergency. This explains both how little is said and how little urgency is in the pilot's voice as he relays the information. It's not just that he's calm, he's concentrating on something else. It's like a guy answering his girlfriend's questions while he's watching sports on TV.

"Unable" is the normal radio response to any request that can't be met. A pilot is unable to accept a runway because it's too short, or unable to turn to a particular heading because there are clouds there, and she's VFR. Or in this case unable to accept any of the offered landing runways because the airplane can't glide that far. The controller is working hard to make this work for these guys. You'll hear a telephone-like beep as the controller picks up a direct line to talk to another controllers to arrange landing priority for the emergency aircraft. The pilot initially wants to return to LaGuardia, then realizes he can't make that and warns the departure controller once that "we may end up in the Hudson." He considers Teterboro, but 22 seconds later he knows that's not going to work. "We can't do it," he says, "We're gonna be in the Hudson."

Realize that the air traffic controllers can't see the airplane. They have a radar trace down to maybe a few hundred feet, but the altitude and position on that updates in jumps, so what they see is not completely up to date. Once the airplane descends below radar they know nothing about it.

The controllers know the airplane has gone down, and probably assume the worst. An interesting transcript to read is the cab coordinator, who is trying to stay on top of all this. You only hear his communication with remote positions, not him talking to his controllers. He can't see what's going on out there either, but he's using all his resources, calling for a controller to get him a police helicopter on frequency. Eventually what I believe is a sightseeing tour helicopter is diverted to determine what is going on. And finally the coordinator gets the good news that there are "lots of survivors."

This New York Times article by Matthew Wald interprets the audio well.

To know more about what was going on the the airplane during all this, we'll need to wait for the cockpit voice recorder transcript to be released.


Anonymous said...

I'm surprised they didn't crash into any helicopters on the way down! There's always swarms of them around the Hudson, especially around that time.

Anonymous said...

From the Class B airspace tape there were two helicopters watching.

Anonymous said...

Hello, Aviatrix. I like your blog- I've added yours to the small junket I read (including Dave's).

I got a kick out of your distaste for turboprops... I'm a Dash-8 Captain, and wouldn't have it any other way!

I hope this crazy career works out for you. I look forward to the "Hooray" post when you finally land a job in a comfy, warm jet and put the days of working for a living behind you.

I'll have some Fin du Monde for you as a toast (or whatever Unibroue product I have on hand when it happens). Good luck!


Anonymous said...

What? Aviatrix has a distaste for turboprops? Well, I never! I'll have to race her one day in my 360kt wonder...of course, she'll be back on the ramp negotiating a complicated hot-start priming ritual... :P

Turbine power!

Aviatrix said...

Indeed, I have no distaste for turboprops. I cried real tears when I didn't get the Dash-8 job I interviewed for. If I could get on with Air Canada Jazz I think I'd have everything I ame to this profession for.

I don't even have a distaste for piston engines, although I sometimes rue the wages and altitudes that accompany them.

Drink your beer before it goes skunky. I don't see any way I'm not to be burning other than avgas for a while.

Anonymous said...

Then I severely misread an archived entry where you apparently were traveling in the back.

I was in no way offended- not at all. For all I know, the DHC8 jobs are rough and you've had enough of that lot. I really should have re-read it. And again, I really got a kick out of my "misperception."

You really do deserve a crack at the title. Persevere. It will happen.

Oh, there isn't a particular bottle of FdM, I keep a running stock of that, Trois Pistoles, Maudite, and Ephemere. Excuse the missing accents.

You ever hear a Yank doing weird stuff with Montreal Terminal near CYQB, say "JACE?"

If it's me, I'll say hello. Our heavy checks are done there, and require an extensive test flight before signoff. Sometimes it takes a few days of tweaks to get it right.

Aviatrix said...

Oh, I know which one now. I was ragging on the company, more the airplane. And I was ragging on everything. I'd been in the field too long and it was time to go home. But I would still fly for them. I'm a little wing-whore, I guess.

Critical Alpha said...

Maybe this has been done to death but I haven't seen it discussed:

Listening to that audio made me wonder again if "cactus" has the same connotations in the US as in Australia.

Here for example as your car departed the road at high speed and careered towards a power pole you might say to your passenger "I think we're cactus here". Or indeed if you lost both engines on take off you might also say "#$$% I think we're cactus". Like the guy who lost both on a Chieftain on take off and put it into the water at Darwin a couple of days ago - Cactus!!

Is it the same in the US? You couldn't have picked a better call sign for that flight if you had tried ;-)

Aviatrix said...

I've never heard cactus used as an exclamation of doomedness. I think Australian slang is as bizarre as your wildlife. You know that Canadian clothing manufacturer Rots sponsors Canadian Olympic uniforms? I think it took the Canadians a week to figure out why the Aussies were laughing so hard.

Anonymous said...


Do you think think that the CVR transcripts or recordings will be released to the public?


Aviatrix said...

I think at least a portion of the CVR transcript will be included with the NTSB report, maybe a year from now. And increasingly audio is being released from CVRs. I don't know why and I don't think it should be, but I suspect this one will come out too.

And then we'll get to see if Captain Sullenberger says "Holy flaming firetrucks!" as well as "my airplane" and "engine restart checklist."

Anonymous said...

Nah, those would be, "non-pertinent remarks," represented by ######

Aviatrix said...

If I had a double engine failure on takeoff over a populated area, they'd be pretty damned pertinent to me. But having seen Captian Sullenberger on 60 Minutes, I rather suspect he just called for the checklist.

I wonder if he needs an adopted daughter.

Anonymous said...

those "new york accents" you sarcasticly refer to are from some of the same people who fished 155 people out of 10-degree water without a moment's hesitation.

Aviatrix said...

Anonymous, no sarcasm was intended. For me, the accent is an initial barrier to understanding. Have you never had to listen extra carefully to understand a Canadian or Australian? From your sensitivity, I can only assume that the controller on the tape has an accent that marks him as from a lower class area of the city. If I say I have difficult understanding someone, be they black white rich poor or from the north south east or west, it's because I had difficulty understanding them, and not because I wish to insult them.

Some days I think I need to subtitle this blog with "I said it was different. I didn't say it was wrong."