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Tuesday, March 28, 2006

Pushing it

I like to consider myself to be safe and conservative when it comes to making a go or no-go decision and certainly know how to recognize my limits. Yet, today's flight really pushed the limits and turned into an true education in weather and instrument flying.
Dispatch slotted us to fly from Manassas to Knoxville, TN, where we'd fuel up before heading down to Atlanta. Ron, my new flight partner, and I met at the airport in the morning and found the weather to be questionable. A low pressure system promised overcasts and icing along our route and what got us concerned was the slim margin between the freezing level and some of the MEAs (Minimum En Route Altitudes) along the way. We didn't want to sandwich ourselves between ice and mountains.
Since I was the pilot flying, Ron deferred to my judgement and I informed dispatch that we weren't comfortable taking the flight. A few hours later, they called and told us the weather had cleared. After a weather check of our own, we still felt unsure eventhough there were no more PIREPs for icing but considered various escape routes and briefed options if things were to turn bad.
Soon after take-off, we were in the clouds at 8,000 feet with no signs of ice and a smooth ride. But it wasn't to last.
Half an hour into the trip, we began picking up light rime ice. We were in and out of clouds and the accumulation was slow so we maintained our altitude. But as we progressed to the south west, more ice collected on the wings so we asked for a lower altitude, which approach promptly granted. A few minutes later we traversed an area of air slightly above freezing, 1 degree Celsius to be precise, and the accumulation melted off.
The true critical leg of our flight was now a few miles ahead of us, starting at Bluefield (KBLF), where the MEA increases to 6,600. We remained at 7,000 feet to stay out of the ice and considered diverting to BLF if necessary. In solid IMC, we crossed the VOR and as luck would have it things started going south. We'd been in light to moderate turbulence for a while with bumps that caused my head to hit the ceiling of the plane. The bumps, however, were now growing stronger and the mountains below created up- and downdrafts that made handling the plane quite a hanful. Ron minded the radios, checked for ice on the wings and watched my back as I wrestled the Seminole through the rough air. To make matters worse, we were now in an area of strong precipitation and ligthening with little altitude to spare below and good chances of icing above. Just the scenario I'd told dispatch I was concerned about.
I knew we had a valley behind us that we could fly to if things got bad and Bluefield wasn't far in case we needed to divert. The atmosphere in the cockpit was tensed, for sure, but we worked well together and got through the area as smoothly as we believe we could.
As we rode the heavier bumps, I experienced the leans, or a false feeling of banking. In this case, my body was telling me the aircraft was in a constant turn to the right, when in fact it was doing the opposite. I focused on the instruments and soon overcame the sensation but learned just how hard it is to ignore your body's instincts.
For the next hour, we were mostly in IMC, occasionally popping in and out of clouds, only to see mountains all around. Big ones, too. The sight was both awe-inspiring and unnerving and we continued to be mindful of escape routes.
After a little under 3.5 hours, we were on the GPS24L approach into Knoxville, landed safely and taxied to the ramp.
Dispatch had plans for us to fly to Atlanta, but Ron and I had resolved to not let anyone influence our decision to scrub a flight if we felt it was the right decision. After a bite to eat and a weather brief, we agreed that overnighting in Tennessee would be best since the rough flight took it out of us. More mountains and IMC paved the way to Atlanta and we were just too tired to take on the challenge safely.
So it's off for badly-needed sleep for now, looking forward to a long day of flying tomorrow. Hopefully a little less eventful.
I've learned a lot about flying today, and a lot about myself.

5 Comments:

Blogger IFR Pilot said...

Great job. Just remember, it's your well-being that's at stake. Dispatch is sitting in a warm office, drinking coffee while you're in the clag dodging ice...

5:31 AM  
Blogger John said...

Nice description of what must have been a tense flight. As you discovered, orographic lifting action around mountains can cool the temperature aloft and increase atmospheric instability. So greater icing and thunderstorm potential is possible around rising terrain. I've seen the outside air temperature drop as much as 8 degrees when transiting mountains.

Icing encounters can be a lot like scud running: After you do it a few times, you think it's a piece of cake. The problem with icing encounters is you can never predicit what you're going to get in flight and what starts as light icing can turn ugly very quickly.

Methinks IFR Pilot is right: It's you guys who are flying up there, not dispatch. This is a good opportunity to learn how to say "no" to a dispatcher and tell them your reasons why.

7:21 AM  
Blogger Capt. Wilko said...

Hi guys,
You're absolutely right. Ron and I actually pictured dispatch sipping coffee while we were fighting the weather and we pledged to be firmer when our instinct told us not to go, which is precisely what we did last night. We took the Atlanta trip this morning instead and all went well, as did the long flight back to Washington from there.
The flight was a lesson in weather flying but also, as you pointed out John, one in saying no when the flight just doesn't appear to be safe.

4:56 PM  
Anonymous Anonymous said...

Of course you must have had a wonderful and smart flight instructor that taught you all about icing conditions and it's hazards...

-Sky Rockets in Flight

5:59 PM  
Blogger Capt. Wilko said...

Yeah, he was ok. Kind of an angry guy though. Lots of anger.
Afternoon Delight.

9:43 PM  

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