Pocono Air Center

 Helicopter Safety Letter

 

May 2006

 Hello again all,

 In this letter I want to deal an issue that many have not even given a second thought to.

 GPS Accuracy!  Yes, but NOT in a GOOD WAY!

Many of you remember the VOR collision hazard that was taught over the years….that is; this was a good place to be particularly vigilant for other traffic, near VOR’s.  Why? Because the airways met there and pilots were navigating over the VOR’s to intercept airways on their next course…..Pretty simple once thought about….VFR and IFR alike.

 

But here is a scenario that played out recently that I thought you all should enjoy.

 

Helicopter “A” (pilot and med crew of two) had departed for a night EMS flight for a hospital to hospital transfer. 

Helicopter “B” (the other guy), had departed on a hospital to hospital mission as well. Then while at the Big City hospital they were launched to go to the same hospital we were leaving from. (Not known to me until after the flight) 

Now you are correct if you are thinking that Helicopter “A” and “B” are going to find each other in the night sky.  You are absolutely correct….They found each other and how they found each other was due to the great accuracy of GPS (3-5 meters).

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Anyway, back to the story….Helicopter “A” and the ever watchful crew (They usually spot obstructions and traffic like eagle eyed wizards) departs transferring hospital after safe arrival and we head en route to big city hospital 40 miles to southwest.  After lifting we immediately call  approach (their airspace begins in about 30 miles )and get “radar contact” with our regularly assigned beacon code, along with a “proceed on course to destination hospital”, well within approach airspace. Approach was busy with weather diverts for the airplanes and had not the time to issue traffic advisories so far out for a low level helicopter.   Just by chance I was monitoring approach secondary frequency and heard another controller terminate radar service for northeast bound helicopter “B” and controller gave helicopter “B” distant traffic at “12 o’clock and 20 miles opposite direction.” 

Could this be us???, the traffic issued to helicopter “B” so far out and on another frequency?  Yes I thought certainly a good chance….I reached out for Helicopter “B” on the helicopter air to air frequency and got no response after several spaced out attempts.  After a few minutes I began to get a very un-easy feeling about the chance that the two helicopters could be a hazard for each other.  I at first started to shrug it off as night time jitters and 2:00am over cautious me!  Then I asked the crew, who was working hard to care for their patient, to help search for traffic that may or may not be out there……….They must have been thinking……”What is he looking for, who else would be out here at this time of night in this kind of weather, down this low?”

Well things started to happen pretty quick at this point as I became more concerned as the time for opposite direction traffic in the same piece of night sky was about to occur…(well maybe, but I just had a hunch). I began flashing the landing light just in case and turned the search light left and right and up and down to introduce motion…..I interrupted ATC and asked for traffic advisories on ANY nearby traffic, particularly opposite direction…Crew came alive on the intercom, pointing out traffic and ATC was spewing out the traffic at 12 o’clock and 1 mile, all at once and mostly gibberish in my helmet at the time due to everyone speaking at once……..The other pilot must have been thinking the same thing or saw our lights as we both veered right and averted a certain mid air at 800 AGL.  I had seen his lights just briefly before turning to avoid.

The proximity of the two helicopters I do not know exactly.  Night makes it very difficult to accurately estimate distance.  I can tell you my heart was racing. After chatting with the other pilot later that evening, I found out that we were at the same exact altitude and had identical altimeter settings as issued by Approach.

The discussions between the two pilots revealed we had both dialed in direct to the two hospitals while on the ground and that due to the accuracy of our GPS’s we nearly found each other nose to nose in the night sky. DIRECT TO, almost got us DIRECTLY in big trouble! I later called approach control and gave the controllers a big thank you for following the rules and good practice by issuing the distant traffic to the helicopter that was leaving their airspace and enabling me to pick up on the transmission.

Anyway, many lessons learned.  One was to consider varying course off the little pink line and try to keep things a little less accurate once in a while….Another is to go with that gut instinct, as I had tried hard to discount it due to the mission, and the odds, along with the “BIG SKY” theory. Another point might be to tune in direct to from an airborne perspective or after deviating just a bit after departure to give the GPS a new starting point. And lastly, NEVER LET YOUR GAURD DOWN!

GPS DIS- ADVANTAGE!   Yes, but I do not want to fly without one or more!  What a great tool!