Thursday, June 1, 2006
Training Tips: A Good Profile
For a new pilot or veteran, the best takeoff relies on managing initial airspeed and altitude--and a judicious first hover.
Good habits and techniques are essential elements of safe and competent performance in flight.
Experienced flight instructors cite lapses in sound takeoff practices and techniques among the most common and troublesome mistakes they observe in pilots, whether they are new to the cockpit or have been flying for years. In the last edition of Rotor & Wing's Helicopter Training special report, we offered a round-up of common mistakes that bore that out ("Common Mistakes in Training (and Flying)," April 2006, page T6). This issue, we focus on one of those: managing takeoffs. We turned to a top flight instructor to enlighten us on the subject.
Tim Tucker spent 27 years instructing for the U.S. Army, first as an active-duty aviator, then as a reservist and civilian. Back in 1979, he bought the first Robinson R22 sold on the market, Serial No. 3. R22 No. 1 crashed into the Pacific during the certification flight test program, Tucker explained. It was recovered after three days in the drink, but was unsalvageable. Frank Robinson had No. 2 built to complete the type certification work. No. 3 was built to prove to the FAA that Robinson Helicopter Co. could manufacture aircraft true to the type certificate, and therefore gain the production certification Robinson needed to start selling the aircraft. When he got it, Tucker was waiting.
"I've been flying the R22 ever since," Tucker said.
When Robinson kicked off its safety course, the company tapped Tucker as chief instructor for it. He's been teaching the course ever since. Tucker was named the Helicopter Assn. International's Flight Instructor of the Year in 2000. In 2004, he won HAI's Joe Mashman Safety Award for "outstanding contributions in the promotion of safety and safety awareness throughout the civil helicopter industry." Among the many plaudits it contained, the Mashman Award citation noted that Tucker authored the Robinson R22 Flight Training Guide, "which has become the foundation for R22 flight training around the world," and has since 1984 "been one of the country's most active FAA designated pilot examiners, and one of only a handful authorized to conduct tests in 10 different makes and models."
Tucker has accumulated more than 18,000 hr. flight time. All things considered, he sounded like a good source for tips on a proper takeoff.
Many of the things that catch his eye about takeoffs, he said, are really matters of preference in techniques or practices. "Like in many things, there are perhaps a number of different techniques that could be used," he explained. "Some techniques are better than others, and people's reasons for certain techniques vary."
There are a few things that don't fall into that category but rather are practices every pilot should use. No. 1 among them is flying a prudent takeoff profile for every normal takeoff.
"The most important thing is to make the takeoff in accordance with the recommended takeoff profile on the height/velocity diagram," Tucker said. (Height/velocity diagrams for the R22 and R44 are printed here).
The hitch, of course, is that not every aircraft type's documentation includes a recommended takeoff profile. The profile is a requirement of FAR Part 27, which took effect in the mid-1970s. Aircraft certificated before then, such as the Bell JetRanger, may have height/velocity diagrams with no dashed line for the recommended takeoff profile. That should not be an impediment, Tucker advised.
"I still think one can look at the height/velocity diagrams and very easily discern what a recommended takeoff profile would be," he said. "It would be a profile to keep one out of the shaded area of that height/velocity diagrams."
Basically, what every pilot should do, he said, is find a combination of airspeed and altitude for the helicopter he or she flies that will keep the aircraft out of the shaded area.
"For whatever helicopter you're flying, you could come up with one airspeed and altitude," he said. "If you made sure on your takeoff that your skids stay below that altitude until you reach that airspeed, that would keep you on that profile." Once you get to that airspeed, you can safely allow the aircraft to climb.
As an example, for the R22 taking off at sea level and a gross weight of 1,370 lb., that combination might be 25 ft. agl and 40 kt. indicated airspeed. You can see on the R22 height/velocity diagram that the intersection of those airspeed and altitude lines is on the upward-curving line at the base of the shaded area of the diagram (for sea-level performance and the other specified conditions). So keeping the skids below 25 ft. would keep you out of the shaded area.
Tucker stressed that this practice assumes you have no obstacles or barriers in front of you on takeoff. You could not do this taking off from a confined area, with trees around you, for instance.
As for preferred techniques, Tucker said, one he stresses to pilots he instructs is to take off with the power setting at which you can just hover. "Not every single time," he said. "But a substantial number of your takeoffs should be made with just hover power, where you just kind of have to nurse the aircraft into flight, so to speak."
The advantage of this is that if you find yourself in a situation in which you are hovering at all the power you have available, you're familiar with the situation and know you are capable of flying the aircraft. Many pilots get sloppy, Tucker said, and routinely pull more power than they need to fly. Placed in the same situation, they would be uncertain of their ability to fly.
To demonstrate this--and Tucker emphasized that this is an instructional technique, not something you should try often or alone--he will have a student put his left hand in his lap so he can't increase the collective, then have him make the takeoff with cyclic alone.
"That is a demonstration, first of all, that it can be done and, two, to develop the discipline to slowly edge it into flight rather than pull power and go."