Saturday, October 29, 2011


The terminal area forecast for KDCA that issued at 18Z yesterday (recovered from the marvelous OgiMet site) had me motivated to get N631S and myself airborne and headed toward the DC area without undue delay. The lines for "FM2100Z" and "FM2300Z" are relevent:
TAF KDCA 281740Z 2818/2918 06005KT P6SM SCT140 SCT170 BKN250 
FM282100 08004KT P6SM VCSH BKN060 OVC090 
FM282300 10004KT P6SM -RA FEW020 SCT040 OVC080 
FM290300 07005KT 6SM -RA BR SCT020 OVC030 
FM290600 03006KT 5SM -RA BR SCT015 OVC025
FM290900 01007KT 6SM -RA BR FEW007 OVC011 
FM291100 36009KT 4SM -RASN BR SCT008 OVC012 
FM291500 35011G18KT 3SM -RASN BR FEW005 BKN008 OVC011 
FM291700 35015G24KT 1SM -SN BR BKN004 OVC007=
The 21Z line in the TAF for KBWI was about the same. I could get past Baltimore with a broken ceiling at 6,000 feet (BKN060) and for arrival I could work around "showers in the vicinity" (VCSH). But the freezing level was going to be somewhere around 3,000 feet which made the forecast for 23Z, calling for light rain (-RA) and an overcast at 3,000 (OVC030) a "no-go" condition. My conclusion was that I'd better be on the ground at Potomac Airfield (KVKX) well before 23Z (7:00 PM EDT).

Conditions were quite good departing KBDR and stayed that way until I reached the Allentown Approach airspace. From that point onward the overcast was solid and at 8,000 feet it looked like I could reach up and touch it. On the positive side of the ledger, winds aloft were light and I was making good speed over the ground (mostly between 130 and 140 knots).

I had to smile looking at the screen showing the NEXRAD returns when N631S and I were abeam of Allentown. The Outside Air Temperature was 27 degrees, and to look at the green area ahead, you might think that there was a problem in the making. NEXRAD was indicating lots of moisture, and that added to sub-freezing OAT's can mean ice! But, if you go ahead and click on that screen shot, you'll see a picture taken seconds later that shows what I was seeing straight ahead through the windshield.

The hint is in the color of the triangles next to the ABE and RDG airport symbols. Blue means good VFR weather, and that held up all the way across Baltimore and into KVKX. This was the METAR in effect as I crossed the BAL VOR:

KBWI 282054Z 11005KT 10SM FEW060 BKN110 OVC150 09/M02 A3021 RMK AO2 SLP231 T00891022 53001\
And this was the one for Andrews AFB (KADW) as I was landing a couple of miles away at KVKX:
METAR KADW 282055Z AUTO 11003KT 10SM FEW075 SCT090 08/M01 A3022 RMK AO2 SLP236 T00791007 53002 $=
N631S was snug in its hangar well before the rain began, about an hour after the TAF had forecast:
KADW 290016Z AUTO 07003KT 10SM -DZ FEW024 BKN044 OVC055 07/00 A3021 RMK AO2 DZB0016 SLP235 $

Monday, October 17, 2011

Into the Darkness

Hindsight being consistently 20-20, I now find myself looking back on last Friday's flight from Bridgeport (KBDR) to Potomac Airfield (KVKX) with acute interest. The interesting bits came in three distinct parcels; I'll describe them in turn.

Part I

The previous post reviewed my planning for the flight, and included an off-hand comment that it's the time of year when one needs to think "less about, 'Will there be convection issues?' and more about 'Will there be ice?'" Famous last words.

As N631S and I were taxiing for departure, the controller advised that ATC was not providing IFR releases for aircraft headed west or south "due to weather." I said I'd park and wait it out. On the way back to the tie-down I took the screen shot at left, showing the weather that was causing the problem.

I was aware that there was significant weather in that area, but I had felt I could depart and work with ATC to find a route through the line or at worst, turn around and return to KBDR. But that scheme didn't work for ATC! In the busy New York Approach airspace, I guess that there isn't time to work individual aircraft through a line of convection. They just shut the routes down until the weather improves.

So, N631S and I sat on the ramp, checking in with the tower every 15 minutes for an update. After an hour and a half, the answer came back as, "Things are improved over by Sparta...you'd better get taxiing." Which we did!

The screen shot at left was taken soon after departure and shows the break in the line that we were aiming for. With just a few vectors for spacing, we were on our way westward. There were some cloud buildups to go through that looked a little intimidating, but the NEXRAD radar display showed little precipitation and there was no indication of lightning. And in the event, the clouds contained nothing worse than light turbulence.
At left, the view at 8,000 feet, coming out of the far side of that line of weather near the Sparta VOR (SAX). You can see the glow of sunset, a result of the delay in departure from KBDR. I hadn't expected to be logging night time on this trip but it was working out that way.

Part II

In looking at the weather forecast for this flight, it was clear that there might be some flirtation with ice. And near Allentown at 8,000 feet N631S and I found ourselves in the cloud layer with the outside air temperature (OAT) coming down. I wanted to stay at 8,000 as long as possible because the winds were more favorable there than at 6,000. Despite a true airspeed of about 140 knots, speed over the ground was only about 110 knots. Lower, the wind would be more directly "on the nose" and the headwind component stronger. I watched the declining OAT until it reached 34°F, and then asked Allentown Approach for a descent to 6,000. And as expected, about 7 knots of ground speed went away. But that altitude was below the clouds and significantly warmer.

Except for needing to be vectored around an isolated patch of convective weather just north of Lancaster, the balance of the en route portion of the flight was uneventful.

Part III

As had been forecast, the surface winds in the DC area were strong and gusty. And, as expected, the winds at KVKX were moderated by the field's location in a valley. Still, there was enough wind (reported as 7 knots from 260°) to make Runway 24 the clear choice. My final controller from Potomac Approach asked if I had the weather at KVKX and I replied, "Yes, I've picked that up; looks like it'll be Runway 24 tonight."

That elicited an offer that I couldn't refuse. Andrews AFB, which lies about 5 miles northeast of KVKX, was more or less between my position and the approach end of runway 24. I could get a turn toward the airport passing just south of Andrews, provided that I agreed to timely cancellation of IFR (since I'd wind up below Approach's Minimum Vectoring Altitude). Visibility was good, so I said, "Sure, we can do that." To which the controller said, "Proceed direct to VKX while I talk to Andrews."

A few minutes later I was at 1,500 feet, essentially crossing east to west over the approach lights of Andrews' Runways 1R and 1L. I was set up on a left base for 24 at VKX. Having cancelled IFR when I had the beacon in sight, I reported the runway in view and was released by the controller. N631S rolled out on about a 3 mile final.

It was a bit after 8 PM local time, and completely dark. Approaching KVKX from the northeast – something I'd never before done at night – offers only the most sparse ground lighting. The runway lights are clearly visible and welcoming, but the intervening terrain is something of a "black hole". The area is basically flat and featureless and I was down at about 1,300 feet to stay well below the floor of the Class B Airspace.

We've all read the training materials on visual illusions. We've been told about the dangers of the "black hole approach." (Avoiding Black Holes by Dale Wilson gives a good overview.) But now I was about to have the experience.

The visual approach aid for Runway 24 is a two-light VASI (Visual Approach Slope Indicator). Red beside red means you're low. White beside white, you're high. Red with white is just right. As I looked out into the dark night, the VASI was stubbornly red with red. Yet everything else about the sight picture had my ground-dwelling brain screaming at me, "Too high! You're too high! Get down!" I had to consciously remind myself, "It's an illusion. Do not descend. Trust the VASI." I was applying that first rule of IFR flight – trust your instruments! And soon, one of the red lights turned white and I started a descent toward the runway.

The landing itself was uneventful, and I was left reflecting on how a VFR-only pilot, trained to trust his eyes, could so easily be trapped by what I'd just experienced. It's a sobering thought.


Two nights later. Sunday, about 8 PM, N438CP – a Cirris SR-22 – was on a visual approach to Runway 26 at Danbury (CT) Municipal Airport (KDXR). The weather was good. I've flown into Danbury on occasion and can state that the terrain surrounding the airport is interesting at the best times.

The approach to 26 is over a residential neighborhood, presumably fairly dark. About a half mile short of the runway, at a point approximately 160 feet above the threshold elevation, the Cirrus flew into the terrain (reportedly where the red dot appears at left). The pilot, sole occupant of the aircraft, was fatally injured. And now I wonder...was he a victim of the siren call to fly lower that I was fortunate enough to be able to ignore?

Thursday, October 13, 2011

It Looks Like Summer's Over

A friend says that there are two seasons here in the Northeast: "Leaves On" and "Leaves Off". We're now well into the transition to the latter, and the times call for a different approach to flight planning. It's now less about, "Will there be convection issues?" and more about "Will there be ice?"

The plan for tomorrow, as usual on a Friday, is to depart Bridgeport (KBDR) late in the afternoon for the flight down to the DC area (KVKX). I expect that my clearance will take N631S and I west to the Sparta VOR (SAX) then south to Solberg (SBJ), west again to the Allentown, PA area, south across Reading, Lancaster and Baltimore, MD, then on into my destination. The first question is, "What's the big picture look like?"

We've got a surface low just north of Lake Huron, with an occluded front trailing off to the southeast. The map (from the NCEP Hydrometeorological Prediction Center site, reflecting the forecast for 00Z Saturday, i.e., 8 PM EDT) depicts an area of showers covering much of New England and New York along with parts of New Jersey and Pennsylvania. Maryland and Virginia are not included. So, I can may get wet on departure but the arrival at KVKX is likely to be dry.

The latest Terminal Area Forecast (TAF) for KBDR (at 00Z Friday, 8 PM EDT, from the AviationWeather.gov site's TAF page) indicates that the rain will stop about 1 PM tomorrow afternoon and the ceiling will be broken at 2,000 feet – not so bad! Here's the TAF:

KBDR 132342Z 1400/1424 06007KT 2SM BR OVC007 
     TEMPO 1400/1402 1SM -DZ BR OVC006 
     FM140400 10007KT 3SM -RA BR OVC003 
     TEMPO 1409/1412 1SM BR 
     FM141400 14010KT 5SM -RA BR BKN008 OVC012 
     FM141700 15012KT P6SM BKN020 
     FM142200 20011KT P6SM SCT030 BKN100

For another indication of the flight conditions to be expected, I can look at the relative humidity (RH) aloft. The chart at left (collected from the NCEP Model Analysis & Guidance site), also valid for 00Z, shows the RH for the 850 millibar level of the atmosphere (or, about 5,000 feet). Most of my expected route is covered by the lighter green, indicating RH of 70% to 90%. In that range, I can probably expect nice, juicy clouds. (An RH above 90% says that rain is very likely.) I'll be starting out at 8,000 feet and then probably descending to 6,000 somewhere in Pennsylvania, so it's a good bet that I'll get to log a significant bit of actual instrument time.

The really important question is whether icing is a hazard. Given the expected RH data, it's pretty clear that if the Outside Air Temperature (OAT) aloft is below freezing then airframe icing is a real possibility. Let's look at the forecast.

Here's the forecast (from the AviationWeather.gov Winds & Temperatures page) for 00Z tomorrow night, showing isotherms at the 725 Mb level (about 9,000 feet). At an altitude of 8,000 feet (required to stay above the Newark arrivals) N631S and I ought to see OAT's a Celsius degree or two above those depicted. It might be a bit close, but conditions ought to be acceptable going over to Sparta and down to Solberg.

Once in Allentown Approach airspace (i.e., about at the Pennsylvania border), Newark arrivals will no longer be a factor and I'll be able to request a descent to 6,000 feet. (The chart at left shows 00Z temperatures at 800 Mb, about 6,000 feet.) That will be well below the freezing level and should be the end of concerns about icing. The rest of the trip, in warmer air and toward improving conditions, should be uneventful.

It will not, however, be quick. At left, the 00Z forecast winds at 9,000 feet (and the forecast conditions for 6,000 to 8,000 feet are similar). As you see, there will be substantial headwinds to deal with. According to FlightPlan.com, the average headwind component for the flight will be 18 knots and the expected time en route is 2 hours + 24 minutes – a rather tedious trip!

As for arrival conditions, the TAF for nearby Washington National Airport (KDCA) is suggesting that from 20Z (6 PM) there will be showers in the vicinity with generally good visibility and scattered clouds at 1,500 feet under a broken ceiling at 5,000.

KDCA 132335Z 1400/1424 12008KT P6SM VCSH BKN030CB 
     FM140600 18005KT 5SM BR BKN008 OVC015 
     FM141300 22007KT P6SM VCSH BKN015CB 
     FM141800 26010G18KT P6SM SCT015 BKN050 
     FM142000 27012G24KT P6SM VCSH SCT015 BKN050
If one of those "showers in the vicinity" (VCSH) chooses to park right over the airfield, then the RNAV Rwy 6 approach may be necessary but there's nothing to suggest any real difficulty getting in. The forecast wind (for KDCA, 12 knots out of the west, gusting to 24 knots) looks a bit energetic, but the field at KVKX is nestled in a valley and the winds there are rarely as strong as forecast at nearby airports.

So, to summarize:

  • A departure into fairly low, possibly showery conditions;
  • Some near-freezing OATs possible in northwestern New Jersey at 8,000 feet;
  • Steady, fairly strong headwinds throughout;
  • Reasonably good arrival conditions, with a possible shower and perhaps gusty winds.
In short, a fairly typical Fall IFR flight.

Thursday, October 6, 2011

Steve Jobs

I have never owned an Apple product. The controlling, "we-know-what's-best-for-you" ethos that emanates from the Cupertino mother ship was not something with which I can deal. But that doesn't mean I can't recognize just how very good Steve Jobs was at what he did.

He was a unique amalgam of rare properties, combining the design genius of a Frank Lloyd Wright with the marketing savvy of a Lee Iacocca. Of the Jobs quotations that have been sloshing around the online world for the last 18 hours the one that goes to the heart of his brilliance is this:

"In most people's vocabularies, design means veneer. It's interior decorating. It's the fabric of the curtains, of the sofa. But to me, nothing could be further from the meaning of design. Design is the fundamental soul of a human-made creation that ends up expressing itself in successive outer layers of the product or service."
Looking at the phenomenon that is Apple, after sloughing off the non-essential, it is all about product design. In the beginning was the design and from the design all good things flowed. The designs are perfect, with nothing lacking that is needed and nothing present that is not necessary. They are like Hemingway's prose, like the music of Mozart, like a Frank Lloyd Wright house. That was Steve Jobs' genius – that he could so order life that such glorious artifacts emerged as a matter of course.

He did not save lives through his work, nor feed the hungry nor cure the sick. But through his art he taught us how to make our interaction with a technology-intensive world richer and more productive. For that he will long be remembered and honored. And his like will not be seen again in our time.