Tuesday, June 30, 2009

Frontal Weather

Last Friday's trip from Connecticut to Maryland turned out to be an adventure in dealing with frontal weather. It was obvious on Thursday evening that the cold front approaching from the west would require adaptive planning but the details were well in the future so I filed an IFR flight plan for the route from KBDR to KVKX that the Air Traffic Control computer always gives me:

SAX V249 SBJ V30 ETX V39 LNS V93 BAL Direct

By mid-afternoon on Friday it was clear that that was not going to work! Severe weather associated with the front was generating Convective SIGMETs in eastern Pennsylvania and the associated lines of thunderstorms were heading east at about 25 knots...so most of the filed route would not be flyable.

After discussing the situation with Flight Service I amended my flight plan for a more easterly routing:

DPK V16 ENO V379 OTT Direct

This would take me across the sound to Long Island, over Kennedy Airport, down the New Jersey coast to Dover, DE then into Maryland and home. The idea was to get down into the DC area before the frontal weather crossed New Jersey to close off the route.

By the time I got to Sikorsky Memorial Airport, there was nothing much happening. The latest observation was:

KBDR 262052Z 34003KT 10SM FEW110 26/19 A2967 RMK AO2 SLP049 60001 T02610189

Just a slight breeze from the north, with ample ceiling and visibility. However, severe weather was approaching. The situation on the NEXRAD display looked like this:

NEXRAD image of KBDR area at 2033Z 26 June 2009

(You can click on any of the images in this post to view a larger version.)

I needed to be on my way in something of a hurry...and that clearly needed to involve departing to the south. So after pre-flighting N631S with all deliberate speed I called KBDR Clearance Delivery and was unsurprisingly given "Radar vectors to SAX, V249, SBJ,...etc."

My response was, "I cannot accept that clearance due to the active Convective SIGMET over V30 and V39. Request Direct Deer Park, V16 to ENO, direct OTT direct." That produced a "631S, stand by," from the tower and I proceeded to "stand by" for about ten minutes. As the weather approaching from the northwest got to look ever more menacing.

About five minutes before the point when I would have to give up on the trip, the tower called to offer a revised clearance:

Radar vectors to DPK V16 DIXIE V1 ATR BILIT DCA Direct.

Now I knew they did not want me to going to DCA (the VOR on the field at National Airport in DC). But this was not the time to argue a fine point so I read back the clearance, got cleared for takeoff and departed. Wheels off the runway about 5:17 PM. By that point the situation looked like this:

NEXRAD image of KBDR area at 2115Z 26 June 2009

That small white dot just off the Connecticut coast is labeled N631S. (The position is taken from the FlightAware track log.) At that point I was on an 090 vector (i.e., eastbound) assigned by New York Approach for sequencing onto V16. In short order they turned me to the south across the sound, then to the west toward DPK, the Deer Park VOR.

At about this time the weather at KBDR was deteriorating rapidly:

KBDR 262138Z 34013G17KT 10SM FEW026 BKN033 BKN090 24/19 A2968 RMK AO2=

Winds at 13 knots, gusting 17 from the northwest with layered clouds. Just a few minutes later the storm arrived:

KBDR 262147Z 33014G21KT 10SM -TSRA SCT029 BKN048 OVC090 23/16 A2970

Inside N631S approaching JFK on V16, the Garmin GPSMap 396 NEXRAD image showed this situation:

GPSMap396 image 2150Z on 26 June 2009

This display is "track up" so north is on the right. All of that colorful stuff is the frontal weather arriving at the Connecticut coastline. By this point it was clear that I'd easily make the southbound turn at JFK before the weather became excessively entertaining. This occurred at about 2155Z:

Headed away from JFK to the south at 6,000 feet the air was smooth and visibility good.

I listened as the weather closed in on the New York airports and JFK, LGA, TEB and EWR became unavailable for arrivals. Lots of holding instructions were being issued to commercial traffic and a number of crews were expressing concern about fuel state.

I was pleased to be clear of the New York area and looking forward to a period of "clear sailing". But I still had to be concerned about the weather at my destination. My plan was to watch the weather in the DC area. If it closed off early I'd divert to an airport along my route (Atlantic City or Millville or perhaps even Baltimore). If it appeared that KVKX weather was holding up I'd proceed inbound and if necessary divert to the south (possibly to Richmond).

When I was handed off to Dover Approach I took advantage of the opportunity to clear up that nonsense about having DCA in my clearance. In fact, they were surprised because their strip showed me routed after ATR to OTT thence direct to KVKX. OTT is the Nottingham VOR and that made a great deal of sense. Problem solved.

I was keeping a weather eye (pun intended) on a storm cell just to the north of DC and moving ver-r-r-r-y slowly toward where I wanted to go. That was going to be the challenge!

Arrival at KVKX was going to be at about 2340Z and at 2315Z the situation looked like this:

The white dot over the Maryland eastern shore is N631S and the dot just south of the severe weather is KVKX. At this point Washington National (KDCA) was reporting:

KDCA 262312Z 21008KT 10SM FEW030 BKN065 BKN250 29/21 A2970 RMK AO2

Gentle southwest breeze, good visibility, plenty of ceiling. Press on!

I crossed Chesapeake Bay and cleared OTT. Potomac Approach brought me down to 3,000 feet and I could see the weather in the distance. I did not slow the airplane down. By 2329Z I was close in and could see the airport:

A short time later the controller at Potomac Approach, who was staying with me and doing a great job, said that DCA had just reported a major wind shift. But I was just then turning base for Runway 24 at KVKX. I landed in a flat calm at 2337Z:

It should be noted that these NEXRAD images show composite reflectivity and that the surface weather was not as evil as the depiction just above would have you think. I had time to fuel the airplane and taxi to the hangar before the storm arrived in earnest. I watched it rain from inside the hangar for about fifteen minutes and then winched N631S inside and put it to bed.

To summarize this very long post, here is the track graphic from FlightAware:

KVKX did not get the worst of that storm cell but Andrews AFB, just a few miles away, did record some pretty serious weather. At five minutes after the hour:

SPECI KADW 270005Z 09014G61KT 060V120 M1/4SM R01R/0500V2200FTR01L/1200V4000FT +TSRA VV016 20/17 A2976 RMK AO2A PK WND 04061/0001 WSHFT 2350 PRESRR SLP079=

Yes, that was a 61 knot gust at 0001Z during heavy rain.

Monday, June 15, 2009

Today at KBDR

When I arrived at KBDR about 1030 local time this morning, this was parked in the expansive grassy area that lies between the approach ends of Runways 6 and 11.

Sikorsky Memorial is often used by airship operators as a base. It's fascinating to watch them wrangle the things especially in anything more than a trivial wind.

You can see in the photo that the morning was overcast. The METAR that was current as I landed put it this way:

KBDR 151352Z 09010KT 10SM OVC008 16/14 A3007 RMK AO2 SLP183 T01560139

The ILS approach for Runway 6 was on offer and I did in fact break out right around 800 feet. Having the runway appear like that is really one of life's most satisfying events.

As I was departing around 1700 local time last Friday I heard KBDR tower working an FAA Flight Check aircraft that was tasked with an examination of the health of that ILS approach. This was getting done because early that morning, in dense fog and with a 5 knot tailwind, a Pilatus PC-12 overshot and got acquainted with the blast fence at the far end. Fortunately the seven occupants all walked away (although there is substantial damage to the fuselage and wing, and the engine and prop are toast).

The fence is rather infamous. One night back in 1994 eight occupants of a Piper Navajo that went through the same fence died in the post-crash fire. In 2001 a Hawker HS-125 landing in a snow squall did the same thing, but that time there was no fire and the two occupants were not seriously injured.

There is now a plan in existence to remove the fence and install a safety overrun that would be filled with frangible concrete to arrest the motion of an encroaching aircraft. This would entail moving the street that the fence protects slightly to the northeast.

Unfortunately this sensible move has been mired in local politics for years. It seems that while the airport is located in the Town of Stratford it is owned by the City of Bridgeport. For far longer than I can remember (I started flying in these parts in 1993) the two municipalities have been at loggerheads regarding what one side calls "expansion plans" and the other calls "safety improvements".

Perhaps the most recent incident can serve to get the runway overrun protection project off of top dead center...but I shan't hold my breath.

Saturday, June 6, 2009

The Wonder of Flight

I ask people who don't fly, 'How can you not fly when you live in a time in history when you can fly?'

William Langewiesche, 2001

We need, occasionally, to be reminded of the degree to which we are privileged.

On today's 'to-do' list was the fetching of N631S from Manassas (KHEF), to which I diverted last night due to weather (see earlier post), back to home plate, KVKX. I invited my son Rich to tag along in the company of one of his good friends. Rich's friend is a very smart and astute fellow who had not, heretofore, been a passenger in a light General Aviation aircraft. The flight from KHEF to KVKX was an ideal introduction.

I had filed IFR for the short (about 20 minute) flight and we were cleared for the Arsenal Two departure to the Casanova (CSN) VOR, thence vectors to KVKX. Our final altitude was 3000, and the bases were for the most part around 2000. We got to see the inside of a couple of clouds.

My first-timer passenger asked good questions, and maintained a "sterile cockpit" environment for the departure and as we got in close to our destination. We had no problem doing the visual approach into KVKX. Potomac Approach ATC did their usual highly professional job. In short, if I wanted to expose a "newbie" to the best of General Aviation, I couldn't have asked for a better flight.

After landing, fueling, and hangaring N631S we stopped off for lunch and my now-veteran GA passenger asked another whole passel of really good questions. And, he allowed as how the flight had been about as much fun as he could remember having with clothes on!

Made my day, ya' know? We get jaded. We interact with ATC and we "monitor systems" as our excellent avionics take us from Point A to Point B. But we occasionally lose our appreciation of the miracle that occurs each and every time we accelerate down the runway and gently apply backpressure at about 55 knots. We need new eyes to remind us to be grateful. I am, this night, very grateful for what I have been given -- the gift of flight.

That's What an Alternate is For!

Yesterday afternoon. Generally rainy but looking flyable for the weekly commute from Bridgeport to Alexandria.

Everything's goin' good up until about 2330Z. KDCA reports a 1300 foot ceiling and I am cleared for the RNAV (GPS) RWY 6 approach into KVKX. Piece of cake. Enter the approach, fly the course reversal, line up on final and start to descend. 1500 feet at the Final Approach Fix...4 miles from the runway, no joy. Descend to the Minimum Descent Altitude of 680 feet. If I look straight down I see the houses just fine. Looking ahead, I see...nada! It becomes obvious that the ceiling has lowered and this is going to be a missed approach.

I climb away from the airport and report the miss to Potomac Approach. She gives me a climb to 3000, a 180 heading, and a frequency change. The next controller tells me that the bases are reported at DCA at 500 feet. Even the big guys are missing, and it will be at least 40 minutes until they can give me another shot at the approach. "Say intentions."

"Stand by..."

If I go somewhere and hold for 40+ minutes and then spend 20-30 minutes shooting the approach again and I miss again (it will be dark by then and there's no real reason to count on a higher ceiling) then I will have to find somewhere else to go...and by that time I'll have less than two hours of fuel remaining.

I key the mike and ask, "What's the current weather at Manassas?" KHEF is reporting scattered at 1100, overcast 1700,  landing Rwy 34R. I dig out the appoach plates for HEF. There is a very nice RNAV (GPS) RWY 34R with a Minimum Descent Altitude of 620 feet. Sold.

I advise the controller of my intention to go to KHEF and he clears me via radar vectors.

 The approach goes routinely and a half hour later I'm on the ground. At the wrong airport, but on the ground. I rent a car and drive home.

Tuesday, June 2, 2009

Archival NEXRAD Images

In putting together last night's post describing last Friday evening's flight I wanted to include some images of the weather situation in certain areas at certain times of interest. What I needed was archival images from the NEXRAD weather radar system. Turns out that it's easy to obtain them and I thought others might like to see how.

The whole process starts HERE at the NEXRAD National Mosaic Images site. Click on the "Get/View" menu item to go to the Radar Data Access page.

Click the link to NOAA's Weather and Climate Toolkit, which you will need to download and launch on your computer. It's a Java application and it will check to ensure that you have an adequately recent version of the Java run-time environment available.

Now, back at the Data Access page, click the link for the Nexrad Inventory Search tool. You'll be presented with a map showing the locations of all the NEXRAD sites. Click on the one that interests you. On the next page, select the date of interest (available dates range from about 1992 to "the day before yesterday". It takes about 48 hours for the system to crunch all the data and archive it.) Then in the list box, highlight the product of interest (one of the COMPOSITE REFLECTIVITY images is a good place to start). Then click the "Create Graph" button.

Now you are presented with a graphic that displays the population of available images for the date being examined. Below the graphic you can enter a time range (say, the time of interest plus/minus an hour) and your e-mail address. Then click on the "Order Data" button.

In a few minutes the system will send you an e-mail with a link to a dynamically-generated web page that will list the images available during the time period you've specified. The links will be in a format like this: KLWX_SDUS51_NCRLWX_200905292200. The first part is the station identifier and the last part is the date-time group. Click on the one(s) you want to keep and save them to your local drive.

Now, remember when we downloaded the viewer application a few paragraphs ago? Fire that up. It will present a graphical interface window. Pull down the Data menu and click Load Data. This will bring up a Data Selector dialog. Click the Local tab and browse to the data file you saved a minute ago from the web link in the e-mail.

The app should load the data and, Presto! There's your archival NEXRAD image. You can save it locally as a *.png file and manipulate it with any of the usual graphics software.

A useful tool set.

Monday, June 1, 2009

There Are Two Kinds of Weather...

In aviation, there are two kinds of weather: Bad Weather and No Weather. With a map that looked like this at 7 AM on Friday morning, it was clearly not going to be a "no weather" day in the Northeast:
I filed the usual "preferred route" (preferred by the ATC computer, not by me) from KBDR west to Sparta then south to Solberg, west to East Texas (near Allentown), south to Lancaster, then Baltimore then home. But around 4 or 5 in the afternoon, the radar picture was looking like this:
That top lobe of precipitation (with the nice red and orange markings) had a SIGMET wrapped around it and I was pretty certain I didn't want to go there. So I filed a new flight plan, starting at KBDR then going to Albany, Wilkes Barre, way out west to Selingrove, PA, then back to Lancaster and thereafter as previously planned. The idea was to first get around that northernmost bit of nastiness and then build in a big loop to allow time for the weather in the Baltimore/DC area to clear to the east.

So I got to the airport, pre-flighted N631S, and called for my clearance. I got: Radar vectors to Sparta, V188 to Wilkes-Barre, thereafter cleared as filed. Not what I wanted to hear, as the last radar picture I'd seen (above) made the Sparta, NJ option a bit unpalatable. I decided to accept the clearance and if it started to take me where I didn't want to go I'd say "Unable!" and negotiate a better deal.

But once airborne and headed west, things started looking better. The picture below shows the echoes at 5:30 PM, just a few minutes after I departed KBDR. You can see that there is an attenuated region developing between the areas of stronger echoes, just about where I needed to be going. So far, so good...
By 6 PM, the path between the heavy weather areas was open and comfortable to transit. Clearly, I was going to be able to get behind the northern parts of this frontal activity.
Sure enough, here is a screen shot of the XM weather display on the Garmin GPSmap 396 at 8 minutes before 6 PM. I am right over Danbury (KDXR) and looking down the road toward Sparta (SAX) the coast is clear.
Of course, that left the little problem of getting into the DC area. At 6 PM, when everything was looking good up north, this is what the Sterling, VA NEXRAD facility was painting:
I got to Wilkes-Barre about 6:15 PM and the controller there asked if I wanted to join V93 there and go straight south to Lancaster, omitting the "delaying loop" out to Selingrove to the west. I had been watching the trailing edge of that patch of nastiness down to the south and it seemed like there was a good chance of it clearing out by the time I made it down there around 8 PM. So, I accepted the excellent controller's offer and headed down toward Lancaster. By 7 PM (probably somewhere around Reading, PA) the radar picture down in DC was improving:
And here, below, is the 8 PM situation. All of the really nasty stuff is over to the east, beating up the DelMarVa peninsula and the path from Pennsylvania over Baltimore and into the east side of DC looked very nice:
Here is another screen from the GPSmap 396 at 5 minutes before 8 PM. That's a pretty intense patch at the upper left, but it's a good 50 miles away. I've just cleared BAL and am headed down to OTT (the Nottingham VOR) where I can make a right turn into KVKX. It's nice when a plan comes together.
To wrap up, here is the FlightAware track for the whole 2.9 hour flight:
And in case you're wondering, the flight back up to KBDR this morning was smooth, fast and totally uneventful. Not good blogging material, but a nice way to travel.