Friday, April 30, 2010

178 Seconds to Live

178 Seconds to Live was the title of an article I read in the Army's Aviation Safety magazine while in flight school. I'm not sure if the link is the identical article I read way back then, but the gist is the same.

Inadvertent Instrument Meteorological Conditions (IIMC) is considered an emergency and can be life threatening for even instrument rated pilots depending on their currency and competency.

In the early to mid nineties I was working for a small Helicopter Emergency Medical Services (HEMS) Air Ambulance company. Our Air Ambulance was a Bell 206L1 helicopter. It was a VFR only operation, but the pilots were required to be Part 135 qualified and instrument rated. We were not allowed to file and fly IFR on purpose. The aircraft was equipped with minimal flight instruments so that a pilot could safely recover from IIMC if he/she had the skills and competency to go along with his/her instrument rating.

I was on duty in North West Arkansas when I got a call for a night transfer from a hospital in the North Western corner of the state to a hospital in Little Rock. The weather was good enough to make a NVFR flight. It is a little easier to encounter IIMC in the dark than in the day due to the vision constraints the darkness gives us humans. My weather was good though. I had no concerns about IIMC on that night.

The aircraft was manned by an all male crew on this flight consisting of a pilot, a flight nurse, and a flight paramedic. During the flight to Little Rock over the Ozark Mountains one of the medical crew said, "Let see if we can get Robert to tell us one of his off color jokes".

I had not told an off color joke in many, many years since undergoing a born again experience before getting out of the Army in 1979. So, the medical crew was waiting...

I decided to tell them about the cowboy hitchhiking across the desert.

The cowboy hitchhiking across the desert
A cowboy was stuck out in the middle of the desert walking when an indian came along on his little indian pony. The indian decided to give the cowboy a ride, so the cowboy hopped up on the horse behind the indian. Once the cowboy was mounted on the horse, the indian kicked the pony into a little run.

The cowboy said, "Indian! You're gonna kill this horse riding it out here like this and we'll both be walking".

The indian responded, "Um! Faster you go, the cooler you get!" And, the indian kicked the horse into a little faster run.

The cowboy said agian, "Indian I'm telling you you're going to kill this horse riding it like this out here!!!"

The indian said again, "Um the faster you go, the cooler you get!" And once again the indian kicked the little pony into a faster run.

It wasn't long in the hot desert sun that the little pony stumbled and tossed the cowboy and indian rolling across the desert.

The horse lay there and soon died of heat exhaustion. While the cowboy jumped up ranting and raving at the indian saying, "You stupid indian, I told you you were going to kill this horse riding it out here like this! Now we're both stuck walking out here."

The indian said, "Um, him must of froze to death."

The medical crew laughed and didn't bother asking me to tell any more off color jokes. The rest of the flight to Little Rock was uneventful. At the hospital I checked my weather for the return trip home while the medical crew delivered the patient to the receiving station. I saw no weather concerns for the flight home and expected a smooth flight.

Little Rock is situated in the center of the state on the south side of Arkansas river. When we departed we followed the Arkansas River Valley northwest toward Clarksville. It was a dark night with no moon illumination. As I neared the Clarksville area I needed to gain altitude to cross the mountains north of the river for the remainder of our trip to the northwest corner of the state. During my climb I punched into a cloud unseen in the darkness. I had inadvertently entered IMC.

My training immediately kicked in and I began following the IIMC procedures:climb, confess, comply. First and foremost you want to always fly the aircraft, but to do that in IMC you have to transition to the instruments and establish a crosscheck. This can be difficult and sometimes fatal depending on your instrument flying skills. My instrument crosscheck came in easy. I confirmed I was in a climb. I adjusted my aircraft's heading slightly to the south and away from the mountains. Once I was comfortable with my crosscheck I identified my anti-collision light switch and turned it off. When the anti-collision light is allowed to remain on in the clouds at night it can induce flicker vertigo; a well known fact the referenced wikipedia article does not include.

My climb and crosscheck was established, I had eliminated a potential source of flicker vertigo, so I was ready to confess which involves reporting to ATC your emergency condition of being IIMC. Before I talked to ATC I wanted to determine what I was dealing with because my encounter with IIMC was totally unexpected based on my weather report before departing the receiving hospital. My secondary VHF radio was set to the Jonesboro Flight Service Station(FSS). I switched my radio selector to number 2 and keyed my mike, "Jonesboro Radio this is Aircraft such and such in the vicinity of Clarksville en-route from Little Rock to Springdale requesting a weather update along my route of flight."

As soon as I started talking on the radio my radar altimeter started chirping at me. This put a serious torque on my brain. The radar altimeter is set to alert you when you get within a certain proximity to the ground. At night our policy was to set it for 500 feet. I was thinking with some mental anguish, "What is going on! I know I'm farther away from the ground than that!" But when you are inadvertent IMC you never really know for sure. When I stopped keying my mike the chirping stopped. Jonesboro Radio responded to my request with updated weather info along my route of flight, but my brain was in such a distracted state over the radar altimeter chirping at me that I did not comprehend what they told me.

I rekeyed my mike, "Jonesboro Radio repeat please". The stupid radar altimeter chirped again but not as much as the first time with the longer transmission. This time my brain digested what FSS told me. I had just encountered a weather anomaly and should have clear flying for the rest of the trip home. About that time I busted out of the top of the cloud and it was clear the rest of the way home. No more emergency, so I didn't get to the confess part and there was nothing to comply with.

While we were still in the cloud shortly after extinguishing the anti-collision light one of the medical crew members commented, "Look at ole Robert, ain't he cool". If they only knew. While flying offshore I learned that it is usually best when flying with the uninformed to simply smile as if everything is roses even if it's not. After being safely back in VFR conditions I thought about the off color joke I was asked to tell. I wondered how things might have gone if I had given in and told a real off color joke like they wanted me too.

After returning to base I filled out an incident report and sent it to the company's chief pilot. When I was relieved by the oncoming duty pilot I told him of my experience. He said, "Oh that secondary VHF makes that radar altimeter sometimes sound."

"Well" I thought to myself, "thank you very much for letting me know about it." The extra torque on my brain caused by the radar altimeter chirping at me during a critical situation almost cost me my life." FAR 135.65(b) requires the pilot in command to record flight irregularities that come to his attention during flight. I guess the relief pilot who knew about the condition thought it wasn't a serious enough discrepancy to ground the aircraft over when it chirped at him in clear blue and 22 conditions. My personal belief is that the military system for recording discrepancies is far superior than the civilian system for documenting discrepancies, but that's another story for possibly another time. Under the conditions I was faced with that night I didn't even make the connection that it was the VHF radio activating my radar altimeter until the other pilot told me it did that. I guess I should have been using my secondary VHF more during other flights...

Well, there you have my Tall Tale for today. Sorry I missed a couple of days. So many stories, so little time...


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