Sunday, October 21, 2007
Worthy of Respect
A phrase I often quote is "Experience is what you get when you don't get what you want." As an instrument instructor, I do my best to expose instrument rating candidates to real-world IFR for a variety of reasons. One reason is to reset the expectations that many pilots have about the utility of getting an instrument rating.
There is no question that instrument training makes GA pilots safer and the accident statistics back that up. Part of this increased safety is the increased skills that you must gain to earn an instrument rating. I suspect that instrument-rated pilots are safer when the weather is marginal because they are more likely to file IFR than to try to scud run and remain VFR underneath the clouds.
The FAA doesn't require an instrument rating applicant to have flown in actual instrument meteorological conditions. I suspect that many pilots get their instrument training in simulated instrument conditions (with a view-limiting device), without ever seeing the inside of a cloud or only seeing real weather for a few minutes at a time. While I try to get the pilots I train into real IMC, I often have to point out that there is weather that just isn't safe to fly in a small aircraft. I like my instrument candidates to see everything from marginal VFR to real instrument conditions with low visibility, but this isn't always possible. You can't order up rain and low visibility when you want it, though it always seems bad weather arrives when you don't want it or least expect it.
The three main deal-breakers to flying IFR in small aircraft include thunderstorms, icing, and widespread low visibility. Flying at night in instrument conditions, especially in single-engine aircraft or over mountainous terrain, needs to be scrutinized very carefully as it is inherently more dangerous and statistically more likely to be fatal if something goes wrong. When all of these factors are considered, it's obvious that instrument instructors walk a fine line between teaching how to make a no-go decision and when to decide to launch into possibly challenging weather conditions.
My decision to launch on an IFR training flight from Redding back to Oakland late last week was based on the best available information at the time. We reviewed PIREPs that were available, the forecasts, the surface weather reports, and the latest NEXRAD radar images. Thunderstorms were not forecast and the freezing level was about five thousand feet higher than we'd need to fly. The radar showed that a plume of moisture from the northwest was beginning to arrive over Redding and conditions were probably only going to deteriorate if we waited. The plane we were flying was G1000-equipped with XM weather capability, so we'd have a bit more information in flight than most small GA aircraft have.
We received our clearance and checked the XM radar. The three minute old radar image showed a band of green echoes we'd have to fly through to the south. South of Red Bluff, there were no echoes at all. We departed in moderate precipitation with visibility in the 1.5 mile range. The surface winds had decreased a bit since our arrival a few hours earlier, but were still in the 20 knot range.
Once airborne and above 1500' the winds increased to a direct headwind of 41 knots. As we checked in with Oakland Center rains became heavy and our climb rate deteriorated. Center reminded us that we were below the minimum safe altitude for that area, adding that he had an amendment to our clearance and we should advise when ready to copy. At that point the new XM radar image showed yellow to dark yellow echoes. I had to disconnect the autopilot and hand-fly in an attempt to get some sort of climb rate and told Center to standby with the new clearance.
In moderate turbulence and pitching for Vx we saw a momentary climb followed by a 300'/minute descent. I contemplated the options: Press on toward better weather and assume we'd be able to climb higher, turn around and fly back into deteriorating weather, or land at Red Bluff. Just then, we reached a break in the action and the five minute-old XM radar image indeed showed us in an area of lighter precipitation. There was still another yellow band of radar returns that we'd need to penetrate and the strong headwind had reduced our ground speed in the climb to as low as 45 knots. The turbulence had subsided a bit so I turned the controls over to my student and we clawed our way above 3000' before hitting the next band of rain. The turbulence worsened so using the autopilot still wasn't an option.
I wrote down the new clearance, then took the controls and asked my student to enter just the first new waypoint into the GPS. He could barely get his fingers to stay on the knobs, but managed to get it entered. In the meantime, I asked to divert slightly to the right where my eyes and the newly received XM radar image showed lighter precipitation. After another 10 minutes of bumping along with the stall warning occasionally sounding, we cleared the precipitation. The ride smoothed out, we could climb normally, and soon entered visual conditions. We heard another small aircraft approaching Redding from the south that told Center they wanted the ILS approach. I felt it only fair to tell them what we'd just flown through and leave it up to them to decide whether or not to try it. It had taken over 20 minutes to fly the short distance from Redding to just south of Red Bluff, but in that short time my student learned several important lessons:
1) Flying underpowered aircraft in bad weather can be both time-consuming, exhausting, maybe even impossible.
2) There are weather conditions in which you can't rely on the autopilot to fly the plane.
3) NEXRAD radar images, whether received in the air or on the ground, only provide a rough idea of what to expect.
Later in the flight our route was going to take us over a small mountain range near Lake Berryessa and the tops of the clouds suggested that slight mountain wave activity might be present. I suspected the controller was eventually going to have us climb to 8000 feet, so I asked if we could start sooner rather than later. Even with the head start, we found the plane just wouldn't climb above 7,200 feet at Vy. There was a clear break in the clouds beneath us and perpendicular to our assigned route, so I looked at the map to see what VOR was in that direction.
I told the controller we couldn't climb and that we'd likely encounter turbulence on our current course. but suggested that we could proceed south, direct to the Travis VOR, then back on course direct to SABLO intersection if that would work for him. He agreed and this provided another lesson:
4) If you can't do something ATC has asked you to do, be ready to offer one or two alternatives that you could do instead.
Approaching Oakland, the temptation was to cancel IFR and get underneath the clouds for a VFR arrival. I suggested we delay that decision until we got a closer look at the clouds over the hills between our current position and Oakland. Sure enough, the cloud cover was thick and it wasn't at all clear if the bases of the clouds would give us enough terrain separation to get into Oakland VFR. We asked for vectors to the ILS and broke out on the other side of the hills at 2500 feet with plenty of visibility. Looking to the north, it appeared that we could have flown VFR under the clouds if we approached from San Pablo Bay, but that wasn't obvious to us while we were above the clouds. This drove home another important lesson.
5) Never cancel IFR unless you are absolutely sure that VFR will work.
Relating this story to acquaintance of mine, he offered this observation: This single flight was likely all my student needed to develop a respect for flying a small plane in bad weather, but as an instructor I must re-experience that situation over and over with each new student.
I guess that's why I make the big bucks.