When a new Cessna 172, 182, or 206 is rolled out for its first test flight at the Cessna Aircraft Company in Independence, Kansas, how long would you guess the preflight lasts? Thirty minutes? An hour?
"One week," said Dan Andrew, the chief pilot for single-engine production flight testing. Subsequent preflights are shorter — more like those that most pilots do, but more thorough. The daily work done by Andrew's crew of four pilots — and by the experimental test pilots in Wichita — offers quite a few practical tips for not only preflighting, but also for everyday flying.
You don't need to be a daring test pilot with nerves of steel to use their advice, although they do a few things that should not be tried at home. One of the first steps in the production test flight, for example, is called the wing flex. A level turn is initiated using more than 60 degrees of bank (yes, you need a parachute for that, and they wear one). Andrew explains what happens after that.
"It is done to settle everything [fittings] in. Basically we put the aircraft in a bank beyond 60 degrees and just maintain altitude. That pulls 2.5 to three Gs. It pops, bangs, creaks. I do it twice, once to the left and once to the right. Usually the second one doesn't have those bangs to it," Andrew said. The wing flex is done to verify the integrity of the airframe.
Another test is a dive — not straight down as in the movies, but enough to test the aircraft's performance. In an acceleration to redline speed, VNE, the test pilots look for any abnormal wing-heavy conditions. On rare occasions, a skin will "oil can" (flex and make a popping sound as when the bottom of a small oil can is pushed to apply oil to a surface), and in that case a replacement of the skin is necessary. Experimental test pilots — flying aeronautical engineers like Doug Bassett and Alan Shepherd — take their aircraft to about 20 percent past VNE. This is done when any significant aerodynamic changes have been made, such as adding a cargo pod to the Cessna 206, or modifications to the engine cowling design to accommodate the new engines.
But those tests are best left to the test pilots. The most important thing that you can imitate is the test pilot preflight.
"There's an airplane out in the hangar that I have been flying since it was new in 1979," Bassett said. "I preflight it every time like I have never seen it before. You have to do that all the time so that you eliminate the little things that can happen to you. Dan [Andrew] is taking an airplane that has just been put together. We take a test airplane that we are very familiar with. I always tell Dan, 'You've got a harder job than I do.'"
Andrew took AOPA Pilot on a typical production test flight, although in a Cessna 182 demonstrator that was previously certificated. He was asked for preflight tips. We all know the importance of a thorough preflight after an airplane comes out of maintenance. Then, you want to make sure prior to takeoff that every button and switch works, and that every cable is attached. Andrew's running commentary during his preflight sounded like this:
"Do the tires have air in them? Is the strut inflated for the nose wheel? Are the propeller blades in the right direction? Ailerons — when you push one down, does the other come up? Flaps — when they are up, are they all the way in the cove? When you push inward on the flaps when they are retracted, are they seated against the stop? Be sure the rudder is rigged properly. Do you have the right fuel quantity? Do the doors close?"
For owners, or for any pilot who flies the same aircraft frequently, Andrew suggests that you act as your aircraft's physician, and give the aircraft a continual flight physical.
"We look for trends," Andrew said. "We keep the flight-test reports so we can go back and look at our data. That same concept can be carried over to the guy with just one airplane. Jet pilots do it every time they fly. They record fuel flows, fan speeds, temperatures, and use the information for future reference. Record manifold pressure or rpm, depending on whether you have fixed- or variable-pitch propeller. Give it a flight physical — that's what it amounts to.
"Track things like cylinder-head temperature at a given altitude on a given day. If you start to see them going up and down, start looking for the cause. There is something going on. Also, watch your fuel flows.
"Check your stall speeds from time to time to make sure the warning is working as it should. Bugs go in there all the time. Rainwater, too. Check your alternate static source, and run your trim tab from stop to stop to keep it loose and limbered. You may need it some day.
"Calculate true airspeed and watch the trend over time. The airplane is talking to us, if we'll just listen," Andrew added.
Andrew and Bassett also suggested that pilots do a tuneup of their skills from time to time, just as they do for their airplane. Those skills start with basic knowledge of the pilot operating handbook.
"Just follow the handbook," Andrew said. "Most people try to. Be very, very familiar with it and know what your airplane will and won't do. Keep your pilot-skills envelope expanded out to the edges. Don't let it shrink on you. For example, if you don't feel comfortable doing power-on stalls, get out there and do power-on stalls. If you don't feel comfortable doing them alone, get a flight instructor and take the stall to the limit."
Bassett has had an opportunity to observe the skills of customers during stall recoveries, and he has a few suggestions.
"They seem to be very hesitant, a lot of times, in using full control travel — even when they need it," Bassett said. "They seem to think, 'There is a limit there, and I shouldn't go to that limit.' Not true. Use everything at your disposal, if you need it. This applies during stall recovery and during crosswinds or gusty wind conditions when you're landing. I also see a mindset early on during final approach that 'I've got my correction set.' They don't want to change that. You have to be constantly reevaluating that."
Speaking of reevaluation, you may wonder what Bassett and Shepherd do all day. After all, aren't the 172, 182, and 206 known quantities? And in production? What experimental test flying could possibly remain?
"Now we do sustaining engineering," Bassett said, "testing a lot of optional equipment, such as the horizontal situation indicator and cargo pods. The 172 and 182 are fairly well fixed. However, we have been adding things on those as well: a two-axis autopilot, flight-control systems. We just finished an HSI for the 172 and 206. There are a lot of new avionics as well — multifunction displays — things that will just blow your mind."
They are also involved in correcting problems found by the production test pilots.
"When our production guys come up with something [a problem], we get involved in that, as well," Bassett said. "We have been working with McCauley on a few issues. No, you are never idle. We have some drag cleanup we are working on — product improvement — and just have completed a two- to three-week session in the wind tunnel at Wichita State University. It is just general drag cleanup." (On its campus in northeast Wichita, the university operates the National Institute of Aviation Research, which is a major source of testing and analysis for general aviation manufacturers.)
So even experimental test pilots assigned to docile single-engine Cessnas still have plenty to do, and they approach their flights carefully.
"What you'll find is that engineering test pilots are pretty much old ladies when it comes right down to it," Bassett said.
For more information on test piloting, see " The Mercury 13," February 1997 Pilot. Links to all Web sites referenced in this issue can be found on AOPA Online ( www.aopa.org/pilot/links/links9911.shtml). E-mail the author at [email protected].
Want to Be a Test Pilot?
The qualifications are rigorous
Essentially, experimental test pilots are flying engineers, and production test pilots are flying inspectors.
Production test pilots normally have a good mechanical background. Dan Andrew, Cessna's chief single-engine production test pilot, has experience in engineering and as a mechanic. He can fly and trouble-shoot at the same time. Another production test pilot was an ag plane operator before joining Cessna.
As for experimental test pilots, Cessna's Alan Shepherd was a design engineer who learned to fly in the Cessna employees' flying club. He rose to chief flight instructor of that club before getting the call to become an experimental test pilot. He designed the firewall for the new Cessna 172 and seats for the Citation X.
Doug Bassett, another of Cessna's experimental test pilots, helped to design the Cessna 150 and the Cessna 188 Ag Wagon, as well as the Cessna O-2A. He flew for several airlines, but when the last of those went out of business he returned to Cessna where he spent five years as a flight-test observer.
"Nobody steps into being a test pilot without going up through some sort of ranks," said Shepherd.
"Mainly, we didn't have a test-pilot school [when I was hired]," Bassett said. "Now we have the National Test Pilot School in Mojave, California. That is becoming more and more an acceptable route for some companies, if they can foot the bill. The FAA endorses it very highly and sends its own pilots to the school from the FAA small-aircraft certification office." — AKM
To learn more about the National Test Pilot School, visit the Web ( www.ntps.com). To learn about U.S. Air Force test pilots and the Air Force Flight Test Center, visit http://afftc.edwards.af.mil. Links to additional information about test pilots and flight testing may be found on AOPA Online ( www.aopa.org/pilot/links/links9911.shtml). E-mail the author at [email protected].
Cirrus Procedures Are Rigorous
Here are a few extra tips from Cirrus
Here are a few tips from Cirrus Design test pilot Gary Black:
During the takeoff and climbout, check for proper engine acceleration, operation and values, proper flight-control operation, and absence of any leakage from the fuel caps.
When at high power settings, such as when breaking in a new engine, check for lateral and directional trim.
You can check compass headings against section lines, assuming you live in the right area of the country. Check flight instruments for operation and precession. Don't forget the alternate-static and alternate-air systems. Like Cessna, Cirrus performs a dive to VNE so the pilot can listen for air leaks, check for proper propeller governing, and check flight-control operation.
A typical aircraft is expected to require three to five flights before everything on the 14-page production flight-test checklist is checked off. In addition to the functional and airworthiness checks of the aircraft, the production test pilots inspect for cosmetic flaws just as if they were to be the new owners of the aircraft.
At Cirrus Design, production test pilots are required to have a commercial certificate with an instrument rating and a second class medical. While not a requirement, having 2,000 or more hours in a wide variety of aircraft and an engineering degree are desirable. Experimental test pilots at Cirrus have several years of experimental and production flight-test experience with other aircraft manufacturers, and an aeronautical engineering degree. — AKM
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