Aviation stories and tips to help you stay sharp.
By Dan Sobczak
Editor's note: This content does not constitute flight instruction. Consult a certified flight instructor in your area for proper flight instruction.
The Four-Inch Flight: The Mercury-Redstone 1 launch, November 21, 1960. Source: NASA
In the early days of manned spaceflight, America and the Soviet Union were racing to be the first to launch a man into space. NASA had just been established in July 1958 as America's response to Sputnik, the first man-made satellite in space, courtesy of the Soviet Union.
To meet the goal of putting a man in space, that same year NASA began Project Mercury, a program that had to invent itself. Many rocket and space capsule components had to either be invented or adapted from existing aviation and rocket technologies.
Essentially, the NASA engineers were making it up as they went. They weren't experienced enough yet to know what they really needed to know.
Two years later in 1960, it came time for the first test launch of the Mercury-Redstone rocket that would soon take an American into space.
Precisely at zero on the launch countdown clock, the Redstone rocket came to life, smoke billowing out from its Rocketdyne A-7 engine. The rocket lifted a few inches off the launch pad, and within two seconds of ignition the engine shut itself down.
An almost comical chain of events all occurred in the next few seconds: the rocket fell back to Earth and settled onto its launch pad, still upright. The launch escape tower attached atop the Mercury capsule ignited its engines and launched itself thousands of feet skyward away from the Mercury capsule, which was still attached to the rocket. The capsule's drogue, main and reserve parachutes were then ejected from the top of the capsule and hung over the side of the rocket blowing in the light breeze. Strips of chaff, or tinfoil, popped out the top at the same moment.
The entire rocket was now live on the pad, fully pressurized, with the booster's destruct system armed and no way for the engineers to safely secure the vehicle. A light breeze began to inflate the limp parachutes, threatening to topple the now-live rocket into a massive explosion. No one had any idea what to do next.
The failure, now dubbed "The Four-Inch Flight", was a blow to both the rocket engineers and America's confidence in its fledgling space program. The entire NASA team was behind the power curve -- they didn't yet have the experience to anticipate what could happen rather than just react to what was happening.
The expression "ahead of the power curve" has its roots in aviation. In very simple terms, the meaning of the saying usually refers to someone who is able to keep up with what's going on. Conversely, someone who is "behind the power curve" is not quite up to the task or not keeping up with expectations. An example of this idiom could be a person who laughs at a joke minutes later after everyone else gets the punchline.
The saying's true definition and meaning, however, comes from the world of airplanes. Stephen Pope, Editor-in-Chief at Flying Magazine and a commercial pilot who is multi-engine, instrument, and seaplane rated, expertly explained the power curve in his pilot proficiency post Power Curve Blues:
"Every airplane has a power curve. And every power curve has a backside. It's an area of the performance envelope in which induced drag rises dramatically, necessitating considerably more power to maintain a given airspeed and altitude.
"Venturing into this 'region of reverse command' on approach can be particularly hazardous because as you 'drag it in' on final your sink rate will begin to increase precipitously unless you pour in the power. Pulling back on the yoke will only exacerbate the problem, and at some point you might be amazed at how much power is required just to keep you from falling out of the sky.
"The way to remain safely on the front side of the power curve is to lower the nose and add power. This is a bad idea, however, if you don't have sufficient altitude to keep from slamming into the ground. The goal, then, is to avoid venturing into the power curve's backside by maintaining proper airspeed on approach.
"If you don't have a good feel for your airplane's power curve, climb to a safe altitude and experiment by reducing airspeed in 10-knot increments. Once you start to notice that it's taking more and more power to fly more slowly and maintain altitude, you know you've crossed from the front side of the power curve to the backside."
When I was learning to fly, my instructor was relentless on reminding me to always be thinking ahead of the airplane. What are the next two things that need to happen? In other words, be mindful and mentally prepared for what's coming next.
For example, if you're in the before-landing checklist, are you mentally prepared with a contingency plan or course of action should your engine quit unexpectedly?
If you're on a long cross-country flight, what are the next two waypoints that you expect to pass? What is the next set of radio frequencies that you expect ATC to pass you on to?
If you're on take-off, what will you do if you suddenly lose airspeed moments after you take off?
Years ago on a hot July morning at Falcon Field (KFFZ) in Arizona, I was practicing touch and goes in a Cessna 172. On my second take-off I noticed the aircraft wasn't climbing well at all. I initially thought my poor climb performance was due to density altitude.
I scanned instrument panel gauges -- engine instruments were all in the green, carburetor heat was off as it should have been, fuel mixture was properly set, the flaps lever was up where it was supposed to be, and the engine sounded fine. I continued my climb-out, gaining very little altitude as the seconds ticked by.
Orange trees at the approach end of Runway 4R and departure end of Runway 22L at Falcon Field (KFFZ) in Mesa, Arizona. Photo by Dan Sobczak.
I wondered if carburetor ice had formed inside the engine. Carb ice would have restricted the proper amount of fuel and air mixture the engine requires at full power and could have caused the poor climb performance I was experiencing. But it was much too hot that morning and unlikely that carb ice would be present.
Without anything else to go on, I started thinking about the possibility of an imminent engine failure, and what my options would be. I was no more than 500' above ground, well past the end of the runway.
I realized my airplane's climb performance was so poor that -- if this situation deteriorated further -- I might have to land on a city street off to my right -- or worse, land in a grove of orange trees directly in front of me. I knew I didn't have enough altitude to make a 180-degree turn back to the runway.
My eyes scanned the instrument panel gauges a second time. Again, everything looked normal, and the engine sounded fine.
Puzzled, I glanced back over my shoulder toward the airport and discovered my flaps were still fully extended, even though I'd retracted the flap lever on take-off roll. The flaps in their extended position were causing excess drag on the aircraft, which severely limited its climb performance.
The aircraft was flying behind its power curve.
I recycled the flap lever and the flaps moved back to their fully-retracted take-off position. Just as soon as the flaps were retracted, the Cessna began gaining precious altitude, and the rest of the flight occurred without incident.
It wasn't until I changed my perspective that I could see the big picture, and realized my problem of not being able to gain altitude was due to a small stuck micro-switch.
On another flight, I received take-off clearance from the tower and I began the take-off roll. The Cessna 172's gauges were in the green, airspeed was alive and I rotated.
Within moments of beginning my climb and about 50 feet off the runway, my headset became full of static. I couldn't hear a thing. I considered an aborted take-off to put the aircraft back down on the runway.
As I was already halfway down the runway, I decided I didn't have enough concrete ahead of me to abort the flight that quick and manage to roll to a stop on the remaining runway. I had no idea if the tower controller could even hear me. All I could hear was static, and I wasn't sure if he would hear me make my abort call or understand why I had to put the aircraft back down.
Golf courses at the approach end of Runway 22L and departure end of Runway 4R at Falcon Field (KFFZ) in Mesa, Arizona. Photo by Dan Sobczak.
This decision-making flashed through my head in a matter of moments, so I decided to continue on with the flight, hoping the static would clear up.
Moments later still on climb-out, now past the end of the runway, I made a call to tower saying I couldn't hear anything, and could he hear me okay? I couldn't hear any reply through the static.
Seconds later I noticed my airspeed was about 10 knots lower than it should be (76 knots on climb-out is recommended). I was so bothered with the communication problem I hadn't noticed my airspeed dropping.
This time I was flying behind my mental power curve.
With golf courses straight ahead, I considered having to put the Cessna on a fairway because now I'm losing airspeed. "Is this the real thing?" I thought to myself.
Then a thought popped into my head: just fly the airplane -- forget about the radio problem for the moment! Get your airspeed back on track and get back onto the flight profile to make the crosswind turn and onto downwind. Then I can start troubleshooting the static problem.
I verified I was still at full power, trimmed the nose down and gained back airspeed. Turning downwind, I made another call to Tower saying I couldn't hear a thing.
Flying with a headset of static was not what I had planned, so I quickly altered my plan and decided to abort the flight and request a full-stop landing whether he heard me or not. Through the static I heard my call-sign and was confident I heard "cleared to land 4-Right." I read back his clearance and made sure to clarify my full-stop request due to the static.
As I reduced power to make my descent and approach, the static magically disappeared. I heard a clean call back from ATC approving my full-stop request. I made the landing without incident. I thanked the controller for his help, he responded in kind, and complimented me with a good job at handling the situation, which I appreciated him saying.
The lesson I learned through experience that day? If unexpected problems come up, always fly the airplane first! When the airplane is confirmed flying and under control, troubleshooting can begin.
Performing ahead of the power curve or behind it can happen at any time, whether in aviation or life.
With "The Four-Inch Flight", NASA engineers realized they were behind the power curve because they were reacting to what was happening instead of anticipating what could happen. A defective micro-switch caused me to let my airplane get behind its physical power curve, while I let a radio communication problem get me behind my mental power curve.
Training, practice and knowledge will help you stay ahead of the power curve and be proactive rather than reactive when flying, especially when an unexpected chain of events might be developing.
The Flight Chain App team
Dan Sobczak is the founder of www.FlightChainApp.com, a mobile app that helps pilots learn from accident chains by making NTSB reports more convenient and easier to digest. Dan received his private pilot certificate in 2003.
Flight Chain App and its companion blog www.AheadOfThePowerCurve.com are committed to reducing general aviation accidents, helping improve aviation safety, and growing the pilot population.
The only NTSB aviation accident app in the App Store that helps you see and understand the accident chain.
For iPhone and iPad.
Flight Chain App and its blog Ahead of the Power Curve are committed to reducing general aviation accidents, helping improve aviation safety, and growing the pilot population.