Thursday, May 28, 2009
Tuesday, May 26, 2009
Here are a couple of photos from this morning's flight showing the XM Weather display (and specifically the NEXRAD Radar screen) on N631S' Garmin GPSMap 396. The first image shows us over Delaware Bay east of the Smyrna VOR (ENO) near Dover AFB (KDOV) headed toward the LEEAH intersection.
The next image is a little earlier (note...not yet past ENO) and at a wider scale. I had just accepted a reroute. My clearance would have had me turning left at ENO and going up to Cedar Lake (VCN). The Dover Approach controller said he'd need me to descend from 7,000 feet to 5,000 feet unless I wanted to proceed to LEEAH and thence to Coyle (CYN). A quick glance at the NEXRAD display made this an easy question to answer -- take me to LEEAH!
The ride was smooth and the precipitation was light as I proceeded through the "alley" where the returns were absent then headed up to the Atlantic City (ACY) area through the region of green (= light) echoes.
Having this kind of information on the airplane provides tremendous confidence and terrific decision support. You know what you are getting into. With the caveat that you must understand NEXRAD's limitations, this is a remarkable enhancement to IFR safety.
About the limitations: At the lower left of each screen image is a data label indicating the age of the information (i.e., Wx -00:06 indicates data six minutes old). In addition, the actual returns might be about five minutes old before the NEXRAD system processes them. So I am looking at precipitation areas that may be, in this case, 11 minutes out-of-date. You must avoid putting yourself into any situation where a rapidly moving cell traps you because you cut in too close to its downcourse side.
This is a strategic tool and a weather avoidance tool -- not a tactical tool or a weather penetration tool. (The latter is the onboard weather radar that the Big Iron carries.) But used for what it is, the NEXRAD/XM Weather/Garmin 396 system is incredibly valuable.
Monday, May 18, 2009
Friday, May 15, 2009
The (not-really-very) old terminal is being razed to make way for a new executive terminal and hangar complex under the aegis of Volo Aviation. From the linked article:
Wednesday, May 13, 2009
It is looking ever more likely that Capt. Renslow and First Officer Shaw took actions that caused the airplane stop flying. The pressing question is, "Why?" Why did two experienced professional aviators take actions that were so completely wrong? NTSB appears to be looking at such factors as the quality of their training, fatigue and the exigencies of scheduling, and even whether professional performance can be maintained while surviving on the pitifully small compensation paid to aircrew of low seniority.
I look forward to an assessment of the possible impact on this accident of the well-known and widely viewed NASA Tailplane Stall video. This video and the conclusions of the study for which it was produced have achieved considerable notoriety in the aviation world and, I suspect, especially keen interest from those who drive twin-turboprop transports in wintry weather. The actions of pilots Beck and Renslow in the critical moments -- respectively raising the flaps and pulling the yoke hard enough to override the stick-pusher mechanism -- are exactly the prescribed measures for reacting to a tailplane stall and exactly the wrong measures for reacting to an incipient stall of the main wing. I fear that these pilots were sensitized to the dangers of a tailplane stall without having been formally and rigorously trained in the recognition (including both detection and discrimination) and mitigation of a tailplane stall. If so, it's a tragedy that the dissemination of valid and useful safety information may have been mishandled at the operational level in a way that produced fatal misunderstanding.
As always, we await the final report...
Monday, May 11, 2009
Although the forecast for KDCA on Friday afternoon suggested that some thundershowers might be in the area, none materialized. There was some convective activity in eastern PA but my route avoided it with no need for deviations. So in the end, the southbound flight proved uneventful.
Looking at the forecasts of last evening for weather and freezing levels in the DC/MD area it would be easy to expect no significant weather for an 0800 local time departure with temperatures above zero degrees C up to 9,000 feet of so. Not the way it turned out.
At departure there was fairly enthusiastic rain, but with good VFR conditions (with the KDCA METAR giving 9SM visibility and 6,500 broken ceiling). So I departed VFR with a turn to the south. Potomac Approach picked me up right away and cleared me up to 7,000 feet (my filed altitude) and turned me to the east.
At about 6,000 feet the rain turned to snow and at 7,000 feet the OAT was 1 degree. Maybe so, but I was picking up rime on the struts, so I asked ATC for 5,000 which they approved quickly.
The interesting weather lasted until Dover, DE and the remainder of the northbound flight was routine.