Saturday, June 29, 2013

Summer Fun

Yesterday's trip from Connecticut down to the DC area was sufficiently entertaining to warrant a post here. Also, it gives me an opportunity to again express appreciation for the amazing skill and willing team-effort on the part of the controllers who shepard N631S and me along our route and keep us out of trouble. In this instance, particular kudos go to the folks at Harrisburg Approach and Potomac Consolidated TRACON (PCT).

I'd been watching the weather map for several days and the synoptic picture forecast for Friday afternoon wasn't very nice. A cold front associated with a deep trough was approaching from the West and was forecast to stall along the coast on Friday. Conditions would be ripe for lots of convective activity. Thus, the Terminal Area Forecast (TAF) for Washington's National Airport (KDCA) was unsurprising:

TAF AMD KDCA 281852Z 2819/2918 19010KT 5SM TSRA BKN050CB
TEMPO 2819/2820 VRB30KT 2SM +TSRA OVC030CB
FM282200 25007KT P6SM VCTS BKN050CB  
FM290000 27005KT P6SM VCTS BKN050CB 
FM290100 27005KT P6SM BKN050 
FM290400 VRB03KT P6SM SCT130
FM291600 21007KT P6SM BKN050=
I was planning a departure at about 1930Z, so the period of heavy thundershowers (+TSRA) was expected to be over well before my arrival, but the prevailing weather for the whole evening was calling for thundershowers in the vicinity. The TAF's for intermediate locations enroute looked pretty much the same.

I decided to depart anyway, watch the weather carefully, and if necessary, land before things got boisterous and wait it out – overnight if necessary. Despite the highly convective environment, this was "air-mass" weather, not frontal activity. The organized lines of storms accompanying a front defy penetration, while the more scattered weather in store in this case often offers a way through if approached with an abundance of caution, lots of information and plenty of fuel.

Everything was peaceful for the first hour or so, but westbound, passing Allentown (KABE) and approaching the turn to the south onto V39 toward Lancaster VOR (LRP), the NEXRAD display showed that things would soon become interesting. Allentown Approach handed us off to Harrisburg Approach a few miles east of FLOAT intersection. Checking in with Harrisburg, after the normal dialog involving altimeter settings, I asked, "Harrisburg, Skylane 31 Sierra is wondering what weather you're painting along Victor 39 to Lancaster and then south towards Baltimore?"

The controller's reply was, "Everything looks good as far as Lancaster, then there's a band of precipitation, heavy to extreme, from south of Lancaster and to the northeast about 50 miles."

I then asked, "Have you got a work-around for that band? I don't want to go and paint myself into a corner down there."

This drew a "Skylane 31 Sierra, stand by," which meant that I had him thinking about the problem. After a pause of about a minute, the controller came back to me with, "Skylane 31 Sierra, it looks like after Lancaster, Victor 143 down toward the BRINS intersection will keep you clear of the weather. Then you can go direct Baltimore." It was my turn to say, "Stand by." I grabbed the Low Altitude chart from the seat next to me, quickly flipped it open to the panel depicting Lancaster, found V143 (which departs LRP on about a 248 heading) and traced it to the Southwest, and located BRINS. I compared that with the NEXRAD depiction and then pressed the Push-to-Talk switch. "Harrisburg, 31 Sierra likes the looks of Victor 143 after Lancaster. I think that's a plan."

After another minute or two I heard, "Skylane 31 Sierra, you are cleared present position direct to Lancaster, Victor 143 to HYPER intersection, then direct to Baltimore, direct to destination. HYPER is a little further, you'll probably be able to turn toward Baltimore before you get there." I read that clearance back, ending with a sincere "Thanks very much." Looking at the weather depiction and noting that the storm cells were moving to the East, it appeared that I'd be in the clear all the way down V143 – and that indeed proved to be the case.

Harrisburg handed us off to Potomac Approach and N631S and I motored along Victor 143, skirting the Northwest edge of the weather. The Potomac controller gave me the customary amendment to my routing, "After Baltimore, direct Nottingham then direct destination," and about ten miles short of BRINS he gave me a 220 heading, adding, "Turn east direct Baltimore when able. Just let me know when you make the turn." It looked to me like it would be about 20 miles before that would be a fine idea.

I turned N631S toward Baltimore, still in the clear and keeping the weather well off to our left. About 25 miles West of Baltimore, the PCT controller said, "Skylane 31 Sierra, there's some weather moving in to the South of Baltimore; that direct Nottingham route may not work. I'd suggest you tell the next controller you'll need to deviate to the East to stay clear of that weather." I acknowledged that with thanks, and got "Contact Potomac on 119.85."

After checking in with the next sector I requested a left-of-course deviation for weather avoidance. She replied with, "31 Sierra, do you have weather radar on board?" I said, "31 Sierra has a NEXRAD weather display."

The controller then said, "Go ahead and navigate around the weather to the east. Just let me know what turns you're making." I said, "31 Sierra is going to go from present position on a 160 heading for a while, then I'll go direct Nottingham when able." This drew, "31 Sierra, that's approved."

I kept N631S on the 160 heading for 12 or 15 miles, descending first to 4,000 feet and then to 3,000. When I could see past the weather to my right I turned toward Nottingham and said (in response to the controller's query) that I'd like the visual approach to Runway 6 at KVKX.

As you can see from the picture at left, that was a fairly enthusiastic patch of weather off N631S's right wing. The overhanging cloud shelf was pretty dramatic as well.

And here's a half-minute of video recorded in about the same spot:

A few miles to the south, the way was clear for a turn toward home plate and the landing at Potomac Airfield was uneventful. It took about a half-hour to get N631S put to bed in the hangar, and as I was driving off of the airfield the heavens opened and gave forth an impressive deluge, leaving me thinking that timing is everything.

All things considered, the conditions for this flight were pretty challenging. Good on-board weather awareness (i.e., NEXRAD) was a 'no-go' item but the real essentials were a creative and savvy controller at Harrisburg approach who quickly developed a workable re-route, and a couple of smart, and above all flexible controllers at PCT who made it possible for me to complete the trip safely. My profound thanks to all.


Chris said...

Thanks for this terrific example of managing through severe weather in the IFR system! It has been very much on my mind as I have been trying to schedule my IFR cross country to complete my rating while the weather here has been truly abysmal. For this training flight, we've been looking for crummy weather, but not so crummy as what you describe.

Frank Van Haste said...


Thanks for your comment. I think the flight I described is a pretty good example of how CRM applies to the single pilot situation. In our case, we may not have someone in the right seat, but we most definitely have other folks with us on the team. And make no mistake, getting a light aircraft from departure to destination safely requires a team effort.

Hope you get some acceptably crummy wx soon. Good luck on getting the rating finished up and then getting it wet!


Cedarglen said...

Thanks for the great post, Frank. I always learn something when I re ad your en-route posts. Considering that you make this round trip nearly every week, I'd say that you and your friends at ATC have each other well trained. Happy landings, -C.

Gary said...


I echo what the others have said. It's nice to see the system work as a 'team'. Thanks for sharing the flight and great pics of the wx and video.

Good for new IFR pilots and those of us that don't get enough IMC time. A good mental exercise putting oneself in the left seat.

Frank Van Haste said...

Craig & Gary,

Thanks for your comments! I really hope that these wx related posts can help other pilots get a feel for what the system can do.

Best regards,