T.H.ursdays with Tom Hill
I was talking with a non-aviation friend about thunderstorms earlier this week. I was on the phone describing a storm cell developing over the mountains to the east of where I live and observed, "You can see it rising." "Really, you can see it rise from where you are?" "You sure can." I explained newly developing cells can rise thousands of feet in minutes. We aviators know this can result in a bad situation if you incorrectly estimate your aircraft's performance versus the storm's. This discussion reminded me of doing exactly that, putting myself in a bad situation due to overestimating my aircraft's performance. I remember saying to myself, in the middle of the situation, "... I promise, I will never do this again!"
The image was taken at Whitesands National Monument
About 20 years ago, I was flying as an instructor in Lead In Fighter Training at Holloman AFB, flying AT-38's. My Operations Officer asked me to take an aircraft part up to Terre Haute, Indiana, to help fix a broken jet sitting up there. This was a good deal for me as I was volunteering for anything, including flying anywhere. The plan was to two-hop up to Terre Haute through Tulsa, Oklahoma, to get there by the end of the day. Then, I would work my way back home by Sunday. It was a good deal because I got the extra flying and I got to land places I'd never been before.
The first leg up to Tulsa was a complete non-event. The second leg, that's when it got interesting.
Back then, we used to fly T-38's in the mid-to upper 30,000 ft. for two reasons. The first was due to the substantial improvement in fuel economy when flying a turbo-jet aircraft. The second reason was you were usually above the clouds when flying that high... unless there are thunderstorms. Flying above the weather was really important because the T-38 didn't have a weather radar. It certainly didn't have the cool portable satellite radio feeds you can get nowadays. All you had was a Mk-1 eye-ball to stay clear of storms.
I remember blasting off out of Tulsa and immediately encountering a wall of storms building over the Mississippi River. At the time, I was in the mid-thirties and didn't see an obvious path through the wall. But I thought the tops weren't much higher than my altitude. I requested Flight Level 410 from Center, thinking flying over the top would be easy-peasy. As I approached 410, I recognized this wasn't going to hack it. I needed to be a little bit higher. I requested Flight Level 450, which is really high for a T-38, especially when it was configured with an external travel pod like I was to carrying those parts for the broken airplane.
What's the big deal with flying that high in the T-38? If you're flying too slowly and you're really high, you're in the Engine Susceptible Flame-Out Region. This means, at best, you could move the throttles very slowly--one inch every three seconds--without risking snuffing out an engine. Or, if you were in a very slow condition, selecting afterburner could cause an engine flame-out. The engines were very sensitive at those conditions.
I was holding 45,000 ft and 0.85ish Mach in the Soup. No, I did not clear the clouds. I was flying the best instruments I knew how (the T-38 doesn't have an auto-pilot), with no awareness of the building weather cell, barely holding on.
Here's the thing that bugs me to this day about that situation: I allowed circumstances to develop so that I was left with little or no good second options. I couldn't descend at the risk of flying into thicker weather and potential badness. I couldn't climb - the jet had no more thrust. I couldn't turn to get out of the weather because I didn't know which way to go. All I could do was press forward and hope for the best. I try always to keep a good back-up option open in anything I do. In this case, I failed in that respect.
Of course, it got worse. The plane began to buck and jolt a bit with turbulence associated with the storm. Such bumps wouldn't have been that big of a deal except my speed seemed to decrease a little with every one, more into that bad region for the engines. As I was willing my speed to increase, I considered my options. Then, I remember saying a prayer to myself: "God, I promise. I will not try to out-climb a thunderstorm again. Ever!"
Long story short, I broke out of the clouds. The turbulence ended. I didn't get a lot slower though I asked Center for a lower altitude into thicker air. The situation passed without more drama.
Technology is a lot better nowadays. I get a feed of radar data right into my cockpit. I can see where the thicker weather cells are. Integration with Center controllers is a lot better, allowing them to give us better advice when needed. We aren't nearly as blind as we used to be. To this day, though, my lesson is still valid. Remember: even the most experienced aviators have bitten it due to an encounter with severe weather. No one is immune from the wrath of Mother Nature if you put yourself in her cross-hairs.
Cheers
Tom
The first leg up to Tulsa was a complete non-event. The second leg, that's when it got interesting.
Back then, we used to fly T-38's in the mid-to upper 30,000 ft. for two reasons. The first was due to the substantial improvement in fuel economy when flying a turbo-jet aircraft. The second reason was you were usually above the clouds when flying that high... unless there are thunderstorms. Flying above the weather was really important because the T-38 didn't have a weather radar. It certainly didn't have the cool portable satellite radio feeds you can get nowadays. All you had was a Mk-1 eye-ball to stay clear of storms.
I remember blasting off out of Tulsa and immediately encountering a wall of storms building over the Mississippi River. At the time, I was in the mid-thirties and didn't see an obvious path through the wall. But I thought the tops weren't much higher than my altitude. I requested Flight Level 410 from Center, thinking flying over the top would be easy-peasy. As I approached 410, I recognized this wasn't going to hack it. I needed to be a little bit higher. I requested Flight Level 450, which is really high for a T-38, especially when it was configured with an external travel pod like I was to carrying those parts for the broken airplane.
What's the big deal with flying that high in the T-38? If you're flying too slowly and you're really high, you're in the Engine Susceptible Flame-Out Region. This means, at best, you could move the throttles very slowly--one inch every three seconds--without risking snuffing out an engine. Or, if you were in a very slow condition, selecting afterburner could cause an engine flame-out. The engines were very sensitive at those conditions.
I was holding 45,000 ft and 0.85ish Mach in the Soup. No, I did not clear the clouds. I was flying the best instruments I knew how (the T-38 doesn't have an auto-pilot), with no awareness of the building weather cell, barely holding on.
Here's the thing that bugs me to this day about that situation: I allowed circumstances to develop so that I was left with little or no good second options. I couldn't descend at the risk of flying into thicker weather and potential badness. I couldn't climb - the jet had no more thrust. I couldn't turn to get out of the weather because I didn't know which way to go. All I could do was press forward and hope for the best. I try always to keep a good back-up option open in anything I do. In this case, I failed in that respect.
Of course, it got worse. The plane began to buck and jolt a bit with turbulence associated with the storm. Such bumps wouldn't have been that big of a deal except my speed seemed to decrease a little with every one, more into that bad region for the engines. As I was willing my speed to increase, I considered my options. Then, I remember saying a prayer to myself: "God, I promise. I will not try to out-climb a thunderstorm again. Ever!"
Long story short, I broke out of the clouds. The turbulence ended. I didn't get a lot slower though I asked Center for a lower altitude into thicker air. The situation passed without more drama.
Technology is a lot better nowadays. I get a feed of radar data right into my cockpit. I can see where the thicker weather cells are. Integration with Center controllers is a lot better, allowing them to give us better advice when needed. We aren't nearly as blind as we used to be. To this day, though, my lesson is still valid. Remember: even the most experienced aviators have bitten it due to an encounter with severe weather. No one is immune from the wrath of Mother Nature if you put yourself in her cross-hairs.
Cheers
Tom
www.tom-hill.biz
Tom... Thank you for a great story! We all do. Some live to tell about it. Others don't.
Tom... Thank you for a great story! We all do. Some live to tell about it. Others don't.
What is the worst weather you have experienced?
