Embedded CBs(reprinted from "Things My Flight Instructor Never Told Me" by Michael Leighton)
In 1990 I finally had bought an airplane that was capable of serious cross-country flight and I was enjoying it. The 1977 Mooney M-20J was pretty well equipped for a light plane of its time, with dual Nav-Coms, ADF, DME, audio panel with intercom, and a Century 2 autopilot. It was a step up in performance from the Cessna Cutlass I had gotten my instrument ticket in.
I had owned the plane for several months and received plenty of dual from a very experienced instructor I had befriended when I moved to Florida. Feeling good about the airplane and myself, I decided it was time to take the Mooney cross-country. My wife and I headed off with another couple from our base in West Palm Beach, Florida toward Morristown, New Jersey. The weather was typical east coast in the early summer. Haze and low flight visibilities, surface temps in the 90s along the entire route of flight and, of course, the possibility of thunderstorms.
In Florida, if you don't fly anytime there is a chance of thunderstorms in the forecast, you may only be able to fly 25 days a year. But in Florida, thunderstorms are easy to see and avoid
, and typical flight visibilities in the summer are better than 10 miles. I completed my preflight and got an updated weather briefing. The trip, from West Palm to Morristown with a fuel stop in Florence South Carolina, would take about seven hours.
The first leg to Florence went well. Early morning skies over Florida were clear and as we crossed into Georgia we began to see the haze. The visibility at Florence was a questionable five miles, but clear of clouds. While we fueled I checked the weather. The radar was showing a small line developing west of Victor 3 on a roughly northwest-southeast line, moving east at 20 miles per hour. I elected to amend our flight plan to take us up Victor 1, which runs parallel to Victor 3 but is 80 miles to the east on average. The destination weather was good and once north of Richmond, Virginia it appeared we should have a nice trip.
As we taxied out, we were advised of a new sigmet which had just been issued for our route of flight. After takeoff I called flight watch for an update on that sigmet. The line of thunderstorms I had viewed on the radar less than 20 minutes earlier had turned nasty. We had filed for 7,000 feet and as we approached Richmond we began to hear aircraft asking for deviations from the weather. Again, I called flight watch to check on the situation, just as I had been taught. Flight visibilities were now nil, and we were in solid IMC at 7,000 feet. Flight watch reported that the line was moving as before and that we were at least five miles east of the nearest echo. Switching back on the center frequency we could now hear regional airliners frantically requesting course deviations for weather.
Less than a minute later it got really dark in the cockpit. The sky turned that grayish green color that you know is associated with nasty weather. Then I saw the first lightning flash. I turned to my passengers and told them to tighten their seat belts. Then we hit the updraft. I'll never know how strong it really was because the VSI was pinned in the 3,000 fpm up position. I turned off the autopilot, closed the throttle, lowered the landing gear and put the nose down and trimmed to maneuvering speed. Still going up. As we went through 9,000 feet, center asked me to say my altitude. I told them 9,000 and climbing. He asked if I had been assigned 7,000. I answered affirmative but that I was in a cell right now and was just trying to keep the wings level.
He cleared me to deviate as necessary and suggested a heading of 088 degrees. Just as he gave us that heading we hit the downdraft. The VSI swung around in the other direction. Full power, gear up, nose up to Vy and still going down . . . in excess of 3,000 fpm! At that point we penetrated the rain shaft. The noise was unbelievable. The turbulence wracked the plane left and right and as I attempted to turn to the right toward the assigned heading, the plane went up on the right wing at close to 90 degrees of bank. Full left aileron and rudder took nearly five seconds to recover to wings level.
All of a sudden, we popped out of the side of the towering Cu into a clear blue cloudless sky. The feeling of relief lasted on a few seconds as an horrendous sound filled the airplane. It was the sound of 2 to 3 inch hail striking the airframe at nearly 200 mph. We had penetrated the cell from behind and came out the front, under the anvil and the falling hail. We had survived the encounter with the storm only to be assaulted in clear air by ice balls the size of golf balls.
The full extent of the damage didn't become apparent until we deplaned. The entire leading edge of both wings, the tail and top of the rudder looked as if a madman had attacked us with a ball peen hammer. Blue fuel stains on the bottom of the wings indicated we had ruptured every fuel tank seam on the plane. It was a miracle we didn't lose the windshield.
That night I lay in bed replaying the day over and over in my mind. I did everything right, everything I had been trained to do. So how did I get so close to becoming a footnote on an NTSB report? Nowhere in any of my instrument training had anyone ever mentioned that you should never, ever fly in IMC in embedded thunderstorms. That thunderstorm avoidance is strictly a visual thing. And that thunderstorm avoidance gear such as Stormscope and radar (which was not that common in singles in 1990) are absolutely mandatory and still not foolproof for operating in those conditions.
What I should have done, and now do, is operate at an altitude that puts me above the haze so I can see the buildups. I fly around what I can't fly over. This often means operating at 10,000 to 12,000 feet or higher in the summertime. All my aircraft have been equipped with storm detection equipment of one sort or another and I carry a small portable oxygen bottle.
I now make it a point when giving instrument dual to take my students on a cross-country trip that puts them in this situation so they can see for themselves what you can and can't safely fly through. Even fast building Cumulus that haven't begun to spark yet can be dangerous.
The bottom line: DO NOT FLY IN INSTRUMENT METEOROLOGICAL CONDITIONS WHEN EMBEDDED THUNDERSTORMS ARE PRESENT OR FORECAST! Something my flight instructor never told me.