Icing the Dash-8

According to the NTSB, more than 25 accidents occur annually due to inflight icing. Here is an account by a Dash-8 Captain with 5200 hours of logged time explaining icing experiences:

We started picking up Super Cooled Large Droplets or as I call it huge water drops which go beyond a foot after contact before they freeze on the windshield. If it goes farther, then it is getting behind our deicing equipment in my experience. Every time I have seen -8 degrees C and clear ice I had gotten an inch of ice within a minute and also every time requested lower right away.

The worst time was southeast of Aspen where it accumulated at more than 2 inches within the first minute. I lost my windshield completely, put the props to 1200 RPM and told my First Officer who was also a newer Captain flying right seat at the time we needed lower as soon as possible!

We were on vectors and within that first minute we had so much ice on us we had lost 15 KTS which is not normally something the Dash does at all in icing. I knew we could not climb out of it in time, so when ATC gave us lower I had the autopilot off and dove down at 3,000-4,000 FPM to 16,000 FT to get out of that temperature of -8 degrees C. At 16,000 FT we were still picking up light rime but it was +3 degrees C and not a concern anymore. However, that minute and a half or so at -8 degrees C and in Super Cooled Large Droplet conditions had dumped so much ice on the plane I could barely see out my left window at the boots and prop hub.

They were loaded with ice. I felt the plane was limping along. The plane was shaking violently with all the ice on the props. I had had the ice systems on maximum the entire flight. We finally broke out of IMC and [Center] wanted us to call the airport in sight, but I told them we needed to fly for a bit and get lower to melt all the ice as I couldn't see out my window to land. We got lower yet and by -2 to -1 degrees C the ice started breaking off and melting. We finally got cleared for the visual but by the time I started to configure for landing we had melted all the ice.

Excerpted from the Aviation Safety Reporting System (ACN 823412)

High winds at Gary?

Here is the METAR this morning for Gary/Chicago Intl Airport in Gary, Indiana:

KGYY 221245Z 350112KT 15SM BKN250 13/10 A3019

Winds from 350 at 112 knots!? The winds since the early morning hours have been from 350 at 8 to 10 knots, so I'm guessing this is just a bad reading by the automated bits on the field.

Distracted by Tower

Distracted by a Tower request to adjust the transponder, the Captain of a Cessna Citation with 23000 hours (1800 hours in type) crosses the active runway at Houston Hobby (KHOU) without a clearance.

We were taxiing out for takeoff and were cleared to taxi from the FBO to Runway 4 at HOU. As we approached Runway 4, Ground Control called us to ask us to turn our squawk on. I looked over and we were already squawking the proper numbers on both transponders. Rather than let the First Officer handle his job (which he was very capable of doing), I became distracted and taxied across the approach end of Runway 4 to get in line behind a commuter jet holding short of another runway, I believe Runway 35. Of course, my mind was telling me he was holding short of Runway 4 and we were going to follow him. Fortunately, there was no other traffic on the approach to Runway 4 and, therefore, no conflicts with anyone else. This is 'proof positive' that no matter how many hours/years of experience one has, if you lose your concentration for only a moment, it could certainly turn out much worse than this -- a valuable lesson learned by a very experienced pilot. Also, I might add, a very lucky one! This was discovered by Hobby Tower, they told us that we had crossed Runway 4 and to do a 180 degree turn and cleared us for takeoff from the other side. Since there was no conflict -- no harm/no foul, but it is my duty to report this because if this report were to help prevent just one conflict/accident, then it is certainly worth my time.

Report from the Aviation Safety Reporting System (ACN: 818328).

Performance Based Navigation (PBN)

Traffic plots made at Chicago Rockford International without and with a PBN design. Source: Miller, S. 2009. Contribution of Flight Systems to Performance-Based Navigation. Aero Magazine. 2:21-28


The FAA defines Performance Based Design (PBN) as "a framework for defining navigation performance requirements that can be applied to an air traffic route, instrument procedure, or defined airspace". The goal of PBN is to consolidate the different types of RNAV and RNP in such a way as to design and implement more accurate and efficient automated flight paths. PBN is the next step forward in the evolution of aeronautical navigation.

Conventional navigation relied on radio beacons, such as VOR, DME and NDB. After RNAV was introduced, airplanes would fly to waypoints that weren't tied to ground-based navaids. RNP, which is based on RNAV, optimized the airspace even further by replacing strict point-to-point routes with more gradual turns.

According to Boeing, which has included RNP capability in every airplane, PBN will result in a significant reduction in track miles through reduced vectoring, saving time, fuel, and emissions. With PBN, the airplane’s own capability determines whether it can safely achieve the specified performance and qualify for the operation. One example of this is the SAAAR approach (i.e., Special Aircraft and Aircrew Authorization Required). CAT II/III approaches are essentially SAAAR, but they assume you're already lined up on final. An example of a PBN-type SAAAR approach is the Palm Springs RNAV RNP Z Rwy 13R apporach (below), which has a finely tuned narrow obstacle clearance path, optimized turn radii, a seamless vertical path.

Distribution of Flight Rules

I took a quick look at the distribution of flight rules today, focusing on Part 139 airports in the lower 48 (CONUS). Not surprisingly, most airports are VFR or MVFR, making up more than 97% of all flight rules. IFR airports made up 2.23% of the sample. Note that this is just one observation! Currently, the weather in the CONUS is pretty good, with only 3% of Part 139 airports reporting rain, and 22% reporting broken or overcast ceilings.

Low IFR in Roanoke

Roanoke Regional Airport/Woodrum Field (KROA) was featured in a recent issue of IFR Refresher because of it's LDA approaches and rugged surrounds. That LDA may come in handy, but perhaps not handy enough this morning. Currently KROA has low IFR (with a model index of 71) with winds from 150 at 4 knots, visibility 1/2 miles in light rain and fog. Overcast layer at 100. Winds favor runway 15, but the LDA is for Runway 6 and the only ILS approach is for Runwnay 33. Current pressure and density altitudes are 1175 and 4220 feet, respectively.

METAR:
KROA 041354Z 15004KT 1/2SM -RA FG OVC001 13/13 A2992

TAF:
2009/05/04 14:16
KROA 041416Z 0414/0512 15005KT 1/2SM FG OVC001
FM041500 12005KT 2SM -SHRA OVC005
FM041600 24006KT P6SM VCSH SCT012 OVC025
FM042100 27010KT P6SM BKN035
FM050100 31007KT P6SM BKN025
FM050800 VRB04KT 6SM BR OVC007

G1000 PC Trainer

Garmin's G1000 piloy training sim is reviewed by Aviation Mentor:

G1000 PC Trainer