Saturday, July 11, 2009

Losing An Aircraft



It doesn’t appear as if this story is interesting enough to make it into the public’s consciousness. Or, more likely, it isn’t understood well enough. But if this story from the BBC is correct, it is really bad news.

”Although Dakar then generated a virtual flight plan for AF 447 (Air France flight 447), the centre had no radio or data contact with the flight.

Crucially, the Dakar centre did not appear to follow standard operating procedures when contact with an inbound aircraft cannot be made.

These procedures state that if contact is not made within three minutes following the estimated time of passing above a transfer point, then the receiving sector should inform the exiting sector so that adequate measures can be taken.

The Dakar shift supervisor only informed Dakar Rescue Control Centre that AF447 was missing at 0741, some 6 hours after generating a virtual flight plan and 5.5 hours after the aircraft should have entered Senegalese controlled airspace. “


Most civilians think air traffic control is nothing more than watching aircraft on radar or through Tower windows and making sure they don’t hit each other. That is just the glamorous part. Just as importantly, controllers are the aviation version of your mother. We’re supposed to watch over the airplanes we’re entrusted with and make sure they get where they are going.

If you’re old enough, think back to a time before kids had cell phones. If your kid went on a trip, the one thing you warned them to do -- over and over again -- was to “call when you get there”. If they didn’t call within a reasonable time of their ETA (Estimated Time of Arrival), Mom started to worry. If she got worried enough, Mom would get on the phone and track them down. If Mom couldn’t find them, she would make Dad get in the car and track them down.

The Atlantic Ocean is a big, empty place. Radar coverage doesn’t exist much beyond 200 miles from land. Aircraft are required to make regular position reports (I believe it’s every 10 degrees of longitude for east/west flights). If an aircraft doesn’t make a position report, the controller is supposed to call the aircraft to get one within a certain period of time. If the controller can’t reach the aircraft, we’re supposed to initiate a search.

This doesn’t apply over just the ocean. And perhaps it will be easier to understand if we use an ordinary transaction here in the States. When an aircraft lands at an uncontrolled airport (an airport without an ATC Tower), the aircraft usually goes below radar coverage at some point. The air traffic controller working the flight will allow the pilot to switch over to the common traffic advisor frequency at some point, usually with an admonishment to cancel his flight plan.

“Cessna 12345, radar service terminated, change to advisory frequency approved, report your cancellation on this frequency or your down time to a Flight Service Station.”

From the time the aircraft is estimated to land at the airport, the pilot has 30 minutes to cancel his flight plan or we’re supposed to come looking for him.

Section 3. Overdue Aircraft

10-3-1. OVERDUE AIRCRAFT

a. Consider an aircraft to be overdue, initiate the procedures stated in this section and issue an ALNOT when neither communications nor radar contact can be established and 30 minutes have passed since:

1. Its ETA over a specified or compulsory reporting point or at a clearance limit in your area.

2. Its clearance void time.

b. If you have reason to believe that an aircraft is overdue prior to 30 minutes, take the appropriate action immediately.

c. The center in whose area the aircraft is first unreported or overdue will make these determinations and takes any subsequent action required.


For those that are confused, the airport is the “clearance limit” in the above.

Suppose the pilot lands long and goes off the end of the runway. No one else is at the airport to see the crash. The pilot is pinned in the airplane and can’t get out. In 10 minutes, the last controller to work the aircraft notices that the pilot hasn’t canceled his flight plan. Usually, it’s just forgetfulness on the pilot’s part. They have a lot on their minds. He’s got to find a place to park, tie the plane down, unload, etc. He probably has to call his mom to let her know he’s arrived safely. But he has to cancel his flight plan.

In 20 minutes, the controller becomes annoyed. Back in my day, the flight progress strip was sitting in the bottom of the strip bay. (I hope -- nay, pray -- that some smart controller is questioning how it works now. How does your relief know 30 minutes has passed ?) Most of us with radar left the data block on the radar scope too. Those are two important reminders, every time a controller scans his work area.

In 30 minutes, it doesn’t matter what the controller thinks or how he feels, he has to initiate search and rescue procedures. The supervisor and Fight Service usually handle this part and it normally starts with calling the local Sheriff, asking him to find the aircraft (using the tail number of the aircraft) on the airport ramp. If the Sheriff doesn’t find the aircraft, we’ll expand the search until we find the airplane. In this case, the Sheriff finds the pilot off the end of the runway, calls the rescue squad which pries him out and takes him to the hospital.

Now, imagine that you’ve crashed in the ocean and you’re bobbing around on the ocean in your life jacket. You cling to the hope that when your pilot doesn’t make his position report, Air Traffic Control will notice that the flight is missing and someone will come rescue you.

”The Dakar shift supervisor only informed Dakar Rescue Control Centre that AF447 was missing at 0741, some 6 hours after generating a virtual flight plan and 5.5 hours after the aircraft should have entered Senegalese controlled airspace.“

Five hours is a long time to wait to be rescued. It’s a really long time for someone to notice that you’re missing. About ten times as long as it should have been.

I don’t hope that this story gets more attention. The aviation professionals know how bad this situation is and I feel certain they will take action. I do hope that some brand new controller (there are so many of them) is reading this and it makes him think.

Overdue aircraft are serious business for a number of reasons. “Lost” aircraft are a disaster waiting to happen. Every time an aircraft is overdue because the speed was entered incorrectly or the flight plan was activated accidentally, degrades the controller’s confidence in the system. This is nothing new. I saw many a controller in my day just throw a strip away on an overdue aircraft because “clerical errors” (if you will) had become so commonplace. Don’t do it. If an aircraft is overdue, inform the supervisor and let him track it down. 99.9% of the time it will be some type of error in the ATC system. But that 0.1% of the time is the reason controllers exist. Be stubborn enough to do your job and save a life.

Don Brown
July 11, 2009

No comments: