Friday, February 28, 2014

GPS: Curses and some Remedies

The other day, I was driving to a newer destination and somewhere in my journey, the GPS navigation display gave up the ghost, all it would say was…”Searching for satellites.” I looked to see if I was under a canopy of trees, near a mountain, or in a tunnel. None of those criteria were satisfied. I was on a n open road.

Now what?

Fortunately before getting in my car, I had Googled directions to the destination and committed to memory as a redundancy. After a few missed turns and “Recalculating” in my brain, I was able to reach my destination, albeit a little late.

Imagine yourself in the cockpit of an aircraft and the GPS refuses to give up the digital cures. What would you do? The straight and narrow of course is tune the VORs at all times and triangulate your position. Simple enough! But for that you have to have sectional charts or low altitude airways charts, Right? Absolutely! RAIM loss is uncommon but it occurs. Maintenance of satellite feeds are also uncommon but they happen. So the smart flier keeps his brain engaged, his fingers moving the dials and correlates his findings with those of the GPS. The Multifunction Display (MFD) is great but a secondary source of data is always a welcome security blanket. If you are bicoastal flier, turning East or West will take you to the ocean for bearings, easy enough. But in the middle of Nebraska where one stretched out field looks like any other, reliance on other devices, including the compass is a good idea for correlational accuracy and staying engaged. Look outside the window. See the terrain. Do some pilotage periodically. Keep yourself in the know!

Another episode of this navigational saga unfolded the day after, while the GPS navigation was in full functional mode, I missed a turn that it reminded me in its pesky snarly voice, “Turn Right!” I was listening to music at the time. So I took the next turn and now the bossy voice from the GPS said, “Recalculating!” after a brief period it outlined a pathway in solid blue to follow. I did and found that it was circuitous. After 5 minutes it had landed me back to the spot where I had made the turn. What gives? I thought. Well apparently the computer database had not been updated to see the new road connecting my designed path and where I was at the time. The old mind then “recalculated” asked a passerby and taking a few “rights”  and “lefts” I was on my way again.

Now wear the aviation hat of a pilot. What would you do? Suppose errant information inserted into the FMS takes you through a path with higher terrain and you are trying to stay under Visual Flight Rules (VFR) below a cloud deck. Now combine that little fiasco with dimming twilight and haze of fog and now Ground Proximity Warning system. You can see where I am going with this. Remember American Airlines Flight 965 (Boeing 757) that crashed near Buga, Columbia. It was determined by the Special Administrative Unit of Civil Aeronautics as a navigation related accident. Yes, that was a tragedy of great proportions.

Included is a Cockpit Voice Recorder (CVR) data from inside the cockpit:
2140:56 Captain: Why don't you just go direct to Rozo then, alright?
2140:58 First Officer: OK, let's...
2140:59 Captain: I'm goin' to put that over you.
2141:00 First Officer: ...Get some altimeters, we're out of uh, ten now.
2141:01 Captain: Alright.
2141:02 Cali Approach: Niner six five, altitude?
2141:05 Captain (radio): Nine six five, nine thousand feet.
Right bank of 20 degrees begins to decrease. Flight Level Change disengaged, Vertical Speed and IAS modes engaged, altitude passes 8,600 feet.
2141:10 Cali Approach: Roger, distance now?
2141:15 Cockpit Area Microphone: Terrain, terrain, whoop, whoop...
Pitch attitude 4.5 degrees nose-up, roll attitude is 12 degrees right, airspeed down to 234 knots, rate of descent 1,500 feet per minute, altimeter at 8,480' MSL, radar altimeter at 1,476' AGL. Autopilot disengages. Master Warning activated. Engine EPRs at 1.0.
2141:17 Captain: Oh [expletive]..
2141:17 Cockpit Area Microphone: [Sound of autopilot disconnect warning starts]
2141:18 Captain: ...Pull up baby.
2141:19 Cockpit Area Microphone: [Sound of aircraft stick shaker]
Pitch attitude increases to 31 degrees. Aircraft rolls out of right turn and reaches 13 degrees left bank. Master Caution issued as radar altitude decreased below 500' AGL. EPRs increase to 1.35 as radar altimeter decreases to 109' AGL and airspeed decreases to 187 knots. Landing gear and flaps remain up.
2141:20 First Officer: It's OK.
2141:21 Cockpit Area Microphone: Pull up.
2141:21 Captain: OK, easy does it, easy does it.
2141:22 Cockpit Area Microphone: [Sound of autopilot disconnect warning. Sound of aircraft stick shaker stops]
2141:23 First Officer: Nope.
2141:24 Captain: Up baby...
2141:25 Cockpit Area Microphone: [Sound of aircraft stick shaker starts and continues to impact]
2141:25 Captain: ...More more.
2141:26 First Officer: OK.
2141:26 Captain: Up, up, up.
2141:27 Cockpit Area Microphone: Whoop, whoop, pull up.
End of CVR recording.
So to all who live and die by the flash of technology either as a pilot or driving GPS navigation display installed automobile, a word of advice… Remain engaged

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