Friday, April 27, 2007

ELT Redux

I recently received this very cogent comment on my earlier post on 406 MHz ELTs. Many aircraft owners have complained about the cost of replacing their old 121.5 MHz ELTs, so I thought it would be appropriate to promote this comment to a separate posting.
One respondent expressed concern over the cost of replacing the 121.5 ELT in his aircraft with a 406 system. This week, during the afternoon, an aircraft owner reinstalled his 121.5 ELT in his floatplane while it was in his boat house/hanger at his rural home. Unfortunately the ELT was activated. The owner finished up, had supper and eventually when to bed.

The signal was picked up by a commercial overflight and reported. A light aircraft flew a search pattern until dusk but could not see anything. During the evening a C130 and a helicopter were dispatched. Two ground crews were also called in. During the night the C130 was able to resolve the search area to a small general area and made many low level passes, dropping over 20 flares to illuminate the area but they could not see the source of the beacon. The noise of the aircraft plus the flares woke the aircraft owner and at approximately 3am he turned off the beacon but did not notify any authority. The C130 had to return to base as it was low on fuel, the helicopter followed after the beacon stopped transmitting. The ground crews stood down until dawn.

The hydro wires acted as an antenna for the transmitter so the signal was equally strong anywhere in the square defined by the concession roads surrounding the owner’s property. In the morning another ground crew commenced a house by house search and finally located the source.

The respondent should consider the cost the aircraft owner in the above situation is facing;
- Light aircraft plus crew for four hours
- C130 plus crew for six hours
- Helicopter plus crew for four hours
- Three trucks plus ground crews for an average of eight hours per crew.

With a 406 ELT the aircraft owner would have got a phone call and likely would have simply been told to turn the beacon off.
Thank you for your insights, George!


nec Timide said...

Two points, a question and a comment:

If he had a 406 ELT a phone call would have gone to the number registered with the SAR complex for the ELT. If he was there all, good. If not... A 406 ELT in theory would have resulted in a smaller initial foot print (limiting the search time), how the boat house/hanger would have changed that is debatable.

If he checked to see if he was producing a signal after installation (with a handheld or the airplane radio) there wouldn't have been an issue. If he had called in when he turned it off (the JRCC/FSS guys won't eviscerate you over the phone) costs would have been limited.

Can someone who is too ignorant to do the right thing with a 121.5 ELT, or when the CF is expending vast resources overhead, be trused to go to the web site and update the registration/contact data for a 406 ELT?

I never do anything with my ELT, remove, install, carry, drive around, unless I have a handeld tuned to 121.5 MHz. 406 ELTs are better devices, but not a cure all.

John said...


Your first points is valid, but in your second point I think you have confused the issue. The right thing to do after realizing the ELT was armed would have been to call FSS, but at that point the C130 had been in the air for quite some time, probably burning thousands of pounds of fuel. Lastly, your question seems to be rhetorical.

Look, the original legislation that created the ELT requirement was hurried, some might say misguided, a bunch of unreliable ELTs were produced, many of them are still in service, causing unwanted hassles, wasting valuable resources, and costing taxpayers a lot of money.

A week after I posted my original article, I arrived at the Oakland airport to find a Coast Guard Dolphin helicopter circling the north field, looking for, you guessed it, another ELT false alarm.

However we might feel about the discontinuation of satellite tracking for 121.5 MHz ELTs, the fact is that it is happening.

Your argument seems to me to be "ELTs don't cause false alarms, people do." Everyone is entitled to their own opinion, but I don't find that argument particularly compelling. I think 406 MHz ELTs provide a significant improvement in false alerts and I have little sympathy for aircraft owners who whine about the high cost. There, I said it ...

bob said...

I look for lost aircraft periodically flying near the North and South Poles. We are simply closer than any dedicated SAR outfit.

Having an idea of the specific aircraft, and a rough idea (within a 100 square miles)make a HUGE difference in search times.

If you, as a pilot, do not have the aircraft and occupants equipped for a night in your area's worst weather conditions, then the savings of a non-406 equipped aircraft will be lost on you on that one unlucky day.

Anonymous said...

The 406 ELT is a 5 watt digital burst transmission that may include GPS data if connected to a NAV unit. The 121/243 is a 100 miliwatt analog chirp transmission. At these frequencies the signal is subject to a great deal of multipath.

One issue is that the 406Mhz transmitter will only transmit for 24 hours, while the 121/243 will keep going until the battery is dead (no less tahn 50 hours).