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GPS: We're Hooked!


by Michael Lenz Reprinted with permission from FAA Aviation News

It all started innocently enough'somebody realized a LORAN receiver from a boat would work in the air. It was the 90's and things were changing fast. Everyone was looking forward to the next new innovation in navigation, the same way that coffee drinkers look forward to that first cup in the morning. Then came something called GPS and it all seemed too good to be true.

First hand-held appeared'heavy and bulky. Once again many were from marine applications. Then the real aviation panel mounts showed-up on the scene. It was hard to 'Just Say No.' Everybody was doing it and it looked like GPS had become the navigation means of choice. At first they were just novelties rather than our 'real' means of navigation.' With 'Direct-to' capability and a database full of useful information like the 'nearest airport' and frequencies for Air Traffic Control (ATC) and Automated Flight Service Station (AFSS), we quickly forgot about the venerable VORs, NDB's and DMEs that had faithfully served us for so many years.

Some pilots couldn't get enough. We've all seen them'the ones who have a panel-mounted unit and a hand-held GPS receiver. That way, if one quit, they wouldn't have to kick the habit and go back to VORs.

Sun 'n Fun' and EAA's AirVenture - became the Woodstock's of what was new in GPS innovation. Next thing we knew there were even IFR-approach certified GPS receivers. Now we had the monkey on our backs. It was next to impossible to quit the GPS habit. Few even tried.

Let's face it. We're all GPS shooked! That's not a bad thing. What we're really hooked on is the area navigation or RNAV capability when using GPS.

Now this does come at a cost 'and an airline pilot who was flying his personal Cessna 180 while using a new handheld GPS captured it early and amazingly well. The reporter had 15,000 hours total time and held an ATP certificate. This pilot submitted an Aviation Safety Reporting System (ASRS) report. I don't know who this gentleman is because ASRS reports are anonymous. Whoever he is, if he is reading this and would contact me, I'll buy him lunch at the FAA Headquarters cafeteria. (Don't all call at once!) I would be honored to sit down with such a clairvoyant and prophetic individual. Anyway, here's what he said in July of 1997:

I am a 30-year airline pilot flying in a light civil aircraft. The en route wx began to deteriorate and I had to make a 180-degree turn to stay VFR. I was lucky'I found a hole and climbed on top. During the climb, I lost part of my NAV. My new GPS gave me good position info while I worked my way around the wx. I like the use of the battery powered backup to assist in the NAV effort.

The reporter also stated he only sent in the report because he was so impressed with the safety aspect of the GPS with pen light batteries being able to help him out of a situation which could have become a problem. He is quite impressed with the GPS unit and operation. His major concern is that it is so good and so reliable that it may lead people into situations where they should not be. He feels every flight instructor should indicate this factor in big red letters to all students: They cannot rely solely on the 'magic.'

With the aviation community hooked on GPS for more than a decade now, it may surprise you to learn that GPS NOTAMs must be specifically requested from either AFSS (via phone) or DUATs. This is because the NOTAMs, other than GPS, effective for your route of flight are located and displayed automatically. GPS NOTAMs cover such a wide area that they are not listed by a specific location and must be specifically requested.

Here's another ASRS report from August of 1996 that demonstrates the importance of always requesting GPS NOTAMs. This pilot laments the need to ask for GPS NOTAMs. The aircraft was a Cessna 172.

Day VFR flight from Wilmington to Avery County Airport Spruce Pine, NC. Filed VFR flight plan and closed in Hickory, NC. We landed Hickory, NC, and called Avery County Airport for wx into Avery County. Report was minimum haze, good visibility. We departed Hickory with about one hour 45 minutes fuel. We were unable to find the Avery County Airport because of poor visibility. Our GPS told us we were over Avery Airport, but could not see it. New Bern flight watch did not tell us about a NOTAM that all gps systems were inaccurate due to the missile attack on Iraq.

About 30-40 minutes later we landed at the Banner Elk Airport in hopes of taking on fuel, but none was available. We again departed with directions to Avery County Airport. We were not able to locate Avery County after repeated calls to Charlotte Approach. We were told when passing Charlotte's airspace that the radar was out for maintenance below 10,000 feet for five hours, so we could not get vectors to Avery County as planned. With about 40 minutes of fuel remaining, we were still unable to find airport. I then decided to remain in a valley with good visibility over a golf course. The remaining fuel could and would not get us back over the mountains to safety. Our situation was getting desperate. After getting calls and help from local pilots to get us out, but with visibility getting worse, we decided if we ran out of fuel this would be the best option. Our fuel ran out. I set for a landing on the golf course, but several golfers were playing, so I decided to land on a highway. A safe landing was made with no injury to people on ground or to crew. Very little damage to airplane.

What would I do different next time? Refuel in Hickory before going further and receive several hours of mountain flying from a CFI in that area. I would also receive a more detailed wx report from Avery County Airport from a qualified pilot. Had I known the haze was as bad as it was I would have parked the plane and rented a car for the remaining trip.

Callback conversation with reporter revealed the following info: reporter states that his passenger pilot had done all the work obtaining the briefing and planning the flight. He did not request NOTAMs and was not given any. Reporter feels something as important as a GPS change should be part of the normal briefing and one should not have to request it.

GPS NOTAMs are an easy thing to forget during a preflight briefing. This may be because GPS is almost always available. We've become spoiled. By asking for GPS NOTAMs you could save yourself an unpleasant surprise.

Here's a GPS NOTAM issued recently. Note the very large area that could be affected.

GPS 04/009 ZDC GPS IS UNRELIABLE AND MAY BE UNAVAILABLE WITHIN A 275 NM RADIUS OF 2958N/0791500W AT FL400. DECREASING IN AREA WITH A DECREASE IN ALTITUDE TO 229 NM RADIUS AT FL250, 163 NMR RADIUS AT FL100, AND 120 NM RADIUS AT 4000 FT AGL. THE TEST AREA IMPACTS THE WASHINGTON, JACKSONVILLE AND MIAMI ARTCC AIRSPACE. WEF 0604201800-0604202100

Give some thought to a back-up plan if your GPS receiver fails. A simple thing like the batteries going dead can contribute to an accident like this.

About 1830 Central Standard Time, a Bellanca 14-13 crashed in a parking lot of a casino near Tunica Mississippi, while on a personal flight. Visual meteorological conditions prevailed at the time and no flight plan was filed. The airplane was substantially damaged and the pilot, the sole occupant, was not injured. The flight originated from the Moore-Murrell Airport, Morristown, Tennessee, about 1430.

Garmin G 100

The pilot stated that he had flown this trip several times and he did not on this flight perform fuel consumption calculations. He also stated that he was navigating using a global positioning system  (GPS) unit and about 10 minutes before arrival at his planned destination airport, the batteries in the GPS unit failed. He continued the flight looking for the airport and stated that he delayed obtaining assistance from air traffic control and did not attempt to use the VOR navigation system in his airplane to determine his position.  He located a place to perform a forced landing due to fuel exhaustion and after touchdown during the landing roll; the airplane collided with trees then came to rest.

Go ahead and keep your GPS habit - but cover your bases by requesting GPS NOTAM's to make sure GPS will be available. Then, have a backup plan in case of an aircraft GPS or handheld GPS hardware failure. Be ready for the time when you have to quit 'cold turkey.'

Michael Lenz is a Program Analyst in Flight Standards Service's General Aviation and Commercial Division.