This is a developing story here in CT. The area they are searching is probably the most rugged in the state.

Can anyone shed light on why they might not be able to triangulate on the beacon?

Chris

[color:"green"] (Sheffield, Mass.-AP, Mar. 3, 2003 Updated 10:10 AM) _Searchers combed a mountainous area along the boundaries of three states early Monday for a private plane reported missing with a family of seven aboard, police said.

Flight controllers lost radio contact with the single-engine Piper Cherokee Six shortly after 6:30 p.m. Sunday. Sheffield Police Chief James McGarry said the pilot reported the plane was in trouble but he had no details.

Shortly thereafter, controllers got a report from an emergency beacon, believed to be from the missing plane. However, the beacon was picked up by only one tracking satellite, so the location could not be immediately pinpointed.

The Keene, N.H., family, including five children, had been flying home after a visit in Pennsylvania, State Police Lt. Paul Maloney said. He declined to reveal their names.

The plane initially was believed to have gone down somewhere between Sheffield and Sharon, Conn., authorities said. The two towns are about 17 miles apart.

Later, however, the search was expanded to an area extending 40 miles outward from Sheffield, including adjacent areas of New York as well as Connecticut, Maloney said.

A state police helicopter took over the search in Massachusetts at dawn. Strong wind prevented Connecticut State Police aircraft from joining the search.

Temperatures in the mountains were in the single digits early Monday with gusty 15 to 30 mph wind.
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It is a VHF transmitter that is line of sight. The signal may be blocked by terrain. The battery, antenna, or the radio itself may have been damaged in the crash.
The satellites do not triangulate the position with an epirb. That is the job of the Civil Air Patrol volunteers.

Here is the update.


[color:"green"] (Sheffield, Mass.-AP, Mar. 3, 2003 Updated 3:15 PM ) _ State police say three members of a New Hampshire family were killed in the crash of their small plane in western Massachusetts, but four others survived.

A family of seven from New Hampshire had been on board the single-engine Piper Cherokee Six, which had disappeared after the pilot made a distress call Sunday evening.

"There are survivors," said Massachusetts State Police Lt. Ron Sieberg. They were being taken by helicopters to Albany Medical Center in Albany, N.Y., he said.

The wreckage was spotted in the Beartown State Forest, a mountainous area near the Connecticut and New York state lines. The site is about five miles east of the Great Barrington airport, where the plane was reportedly headed, officials said.

The Keene, N.H., family, including five children, had been flying home after a visit in Pennsylvania, State Police Lt. Paul Maloney said. He declined to reveal their names.

Temperatures in the mountains were in the single digits early Monday with gusty 15 to 30 mph wind.





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I guess those are possibilities. I was more surprised that no one had even tried even a simple DF by nulling the signal. Perhaps the transmitter did go out prematurely after the initial activation.

Chris

Hi Chris,

The Emergency Locating Transmiter (ELT) used by most general aviation aircraft operates on 121.5 mHz. This frequency is monitored by satellites orbiting the earth. Part of the delay in reporting of the ELT's is due to the fact that the first pass of a satellite over an activated ELT signal does not immediately initiate search & rescue, the first signal received needs to be confirmed by a second satellite pass. This may take several hours. As mentioned above, 121.5 mHz is line of sight transmission. In mountainous terrain, if an ELT is activated in a valley or gorge, the usable signal available to search & rescue is grossly diminshed.

There are other factors that come into play as well. Most ELT activations are accidental, so there can be a bit of field work involved at the local airports where many ELT's have been set off by wind blowing on the tied down aircraft, various failures of the actual ELT equipment itself, inadvertant pilot/passenger activations (hey, lookit this little silver switch, wonder what it does, click, hmmmm...nothing obvious happened), then it's forgotten until some hot / tired / cold / wet and in most cases, severely irritated (rightfully so, IMO) CAP and/or other S&R personnel using direction finding equipment, finally locate the ELT in question, which is all too often in an airplane tied down with unreachable owners/operators. All this can lead to the "cry wolf too often" issue.

In many cases, other aircraft flying overhead may hear the ELT and report it to Air Traffic Control. When able, many pilots will take to time to circle the area and try to define where it may be originating, and report that to ATC as well. Sadly, there are other instances where fuel does not allow the luxury of time to spend looking in depth as many of these other aircraft are typically are well into their flight.

I've required my student pilots to monitor 121.5 at all times when safely feasible, and have on ocassion, reported activated ELT's to ATC. As far as I know, they were all false alerts, but it only takes one real one to save a life.

Another good thing for pilots to do, is just after shutting down the aircraft, turn on the radio for a moment and check to see if an ELT is going off. Too often, this simple item is overlooked in the rush to leave the airport...

There are more aspects to your original question, but this should cover most of the primary points of the equation. There are a number of S&R folks on these forums that may also jump in with other items of interest.

edit: ELT's have also been known to fail to operate (with disasterous consequences) as well. See the tale of two crashes elsewhere on this site.

Regards,
Comanche7

The problem is that no one but the Coast Guard and Civil Air Patrol have the DF units required. Most military helicopters can DF and track only FM signals which are those used by ground units.

Seems like quite an oversight given that the National Guard is often called out for local emergencies. You'd think they'd at least have a few portable units they could set in the floor of the chopper while they fly around. <img src="images/graemlins/crazy.gif" alt="" />

Just to add to what others have said:

The beacon was only picked up by a satellite. Why couldn't the rescuers triangulate on the beacon? Well, in order for ground or air searchers to do so, they'd have to be close enough to pick up the signal. So it's a "catch-22" situation - in order to find the plane, they have to know where it is. (At least approximately.) Triangulation by ground or air rescuers allows them to pinpoint the location more accurately when the general location is known. I doubt the difficulty had anything to do with lack of the proper equipment, as someone suggested (though that poster probably knows more about it than I do).

Given the fact that only one satellite was able to receive the signal, my guess is that they went down in a deep, narrow valley, in which case the searchers likely wouldn't have been able to pick up the signal until they were practically on top of the downed aircraft.

I understand the searchers did, in fact, locate the downed aircraft within a day and rescued 4 of the 7 occupants.