Monday, July 20, 2015

"My Frequency" Confession

When flying IFR, a pilot "reads back" that is repeats back all the instructions we receive from air traffic control, to demonstrate that we have heard and accept the instruction, and to give the controller a chance to notice if we have heard incorrectly, or if the controller misspoke. It gets a little silly sometimes: the pilot asks for a particular clearance, the controller clears them for it, and the pilot reads it back again, but it prevents us from descending to five thousand when it's only safe down to nine thousand. When I say pilots talk to "air traffic control," we are only sometimes speaking to someone who can look out the window of a tower and see us. We're usually speaking to someone who can see an electronic blip on a computer screen, generated in response to radar return and transponder code information from our aircraft. We may even be talking to someone who merely has a copy of our flight plan and has keep track of aircraft based on our position reports, in an area with no radar coverage. They probably have a map of their area and some cool computer tools to help them. The sky is all parcelled out vertically and horizontally into different classes of airspace, some requiring air traffic control and some not. A pilot might first talk to the clearance delivery position, then call ground for taxi clearance. The ground controller instructs the pilot to contact tower at the hold short line. The tower controller passes us on to departure or terminal and then terminal instructs us to switch to Centre. All the way across Alberta, and much of northern Canada we're talking to Edmonton Center, but as I cross Alberta I'm progressively switched between frequencies, so I'm always in range of the antenna that transmits and receives on that frequency.

The controller might say, "ABC, Contact Edmonton Centre on 132.75" and then I say "ABC, 132.75." I tune 132.75 and then call that controller, saying, "ABC, one five thousand." If a pilot neglects to acknowledge a frequency change, and just goes straight to the next frequency, the poor controller that directed her to change has no way of knowing whether she changed or just fell asleep. And of course she has to check in on the new frequency or the new controller doesn't know that the change has been made successfully. Sometimes the controller's wording is "Contact me now on 133.4." That means the one controller is managing multiple frequencies. "Contact me now" means "Switch to my other frequency" Sometimes they just say that, too, or "Switch to my frequency ..." When things aren't too busy, in remote areas or overnight there are fewer controllers, so one person may manage all the frequencies in a vast swath of airspace. Sometimes the controller sets it up so that all the pilots on the various frequencies she is controlling can hear the controller regardless of which frequency she is broadcasting on, and sometimes we can hear the other aircraft on those frequencies too. This makes it easier for us not to call on one frequency when the controller is speaking or listening on another. Sometimes the frequencies aren't paired this way so we do sometimes talk at the some time as the controller is busy on another frequency, and she has to ask us to go again.

I learned to fly IFR during the day in busy airspace where all the frequencies had their own controllers. I would read back my frequency change instructions, change frequencies, and check in with the next controller. And then I went north and honed my skills in remote areas in uncontrolled airspace where there were no Centre controllers to talk to, just pilots talking to one another, reporting when we changed altitude or passed over waypoints. So it took me a really long time to notice something. Here comes the confession.

If a controller says, "Contact me now on 132.75" you don't need to read that back on the original frequency and then switch frequencies and check in." You can just dial in 132.75 quickly and say, "ABC on 132.75." This did not dawn on my for the longest time. I noticed a pilot doing it one day, when the controller had paired the frequencies, so I could hear the pilot given the instruction to switch and simply acknowledge it on the new frequency. I think most people do this most of the time. Do you?

Tuesday, July 14, 2015

Beating Popular Wisdom

On Saturday, sixteen-year-old Autumn Veatch was on board a Beech Bonanza, a zippy little single engine airplane, with her step-grandparents. Autumn must have been a passenger, as one must be seventeen to pilot an airplane like that in the United States. So her grandmother or grandfather was flying it. They were en route from Kalispell, Montana (at the southern end of the Rocky Mountain Trench) to Lynden, Washington (on the west coast, just south of the Canadian border). This route crosses mountains, some of the most rugged and remote territory in the contiguous United States. The aircraft is capable of flight up to about 25,000, enabling it to climb over some mid-level weather, assuming those on board have supplementary breathing oxygen. I don't know if they did, or if they flew at oxygen-requiring altitudes on this flight. In the US a pilot can cruise indefinitely up to 12,500' without supplementary oxygen, and the mountains in that area are not so high that they would need to be above 12,500'.

Autumn has probably flown with her grandparents before. She looks comfortable in her headset and a photo of her wearing it was available to the press. I don't think that her parents would have given it to them. CBC likely got the photo off social media. My experience shows that reporters will creep the Facebook galleries of a person, their family, employer, and known associates in order to print pictures of them and their family in association with a story. Having an unusual name just makes it easier for them. The Bonanza crossed the Idaho-Washington state line and then dropped off radar. If US radar is anything like Canadian radar in that area, that disappearance itself is nothing to be concerned about. Radar just doesn't cover aircraft below the flight levels as they cross that expanse of mountains. Typically Canadian controllers let the pilot know that they have been lost from radar, and that they are likely to lose radio contact also, then give the pilot a time and frequency to attempt to contact the next controller. But the Bonanza pilot did not ever contact the next controller. The aircraft was reported overdue on Saturday afternoon.

Autumn said that the plane entered a bank of clouds and then crashed and caught fire. Autumn escaped from the wreckage, largely uninjured. and stayed in the area, a mountainous, wooded and probably kind of smoky spot: smoky from numerous forest fires in British Columbia, in addition to the smoke from the burned plane. If she had her phone with her she may have tried to use it, but was unable to get a signal, or perhaps the battery was dead. Searchers were able to track the aircraft occupants' cellphones until about an hour and a half after the plane was lost from radar. Five aircraft equipped with special radios for detecting the missing plane's emergency-locator transmitter searched the mountains, while ground crews focused on the area along their course not far past where they dropped off radar.

The usual advice for anyone in an airplane crash is to stay with the aircraft and wait for rescue. The logic is that the airplane is a large metallic object that may have been tracked on radar and is probably emitting an emergency signal that can be tracked by satellites and search and rescue aircraft, while you are a tiny piece of meat who doesn't know exactly where she is. You are at risk of falling over a precipice, getting more lost and injuring or exhausting yourself. Whether Autumn knew this advice or not, she followed it for about a day and then decided to walk out. It was mostly downhill, but she didn't fall over a cliff. There was a trail and she followed it, walking for a couple of days. She came out at a road, the somewhat ambitiously-named "Highway 20." The road is often closed in the winter, but probably she didn't have to wait too long for someone to drive by. A motorist gave her a ride to the little town of Mazama, where they called 911.

Autumn is physically okay, but the civil Air Patrol has turned the search over to the Navy. Reading between the lines of the story, one can only presume that the grandparents were killed in the crash or the post-crash fire. No wonder Autumn chose to leave the site. I haven't searched for information beyond this one news story. I could probably find that half my assumptions are wrong if I looked a little further, but this isn't news reporting. I've merely added some information based on my own experiences. The NTSB preliminary report isn't even up yet. I don't know Autumn or her family. I just happen to have written a story a couple of years ago that included a sole survivor of a single-engine plane crash walking out of the woods in the northwest, and a damaged Beech Bonanza turned up in our hangar today, so it struck a chord.