Now for my question. As an instructor, I'd like to know if there is a single, preferred technique that students can use to calculate the ETA and fuel burn for the first checkpoint.
One rule-of-thumb method I've seen is to use the planned cruise airspeed and fuel rate for the entire first segment, and then add one minute for each thousand feet of climb, to account for the reduced airspeed and increased fuel burn during the climb. However, it would also be practical to use the performance charts to perform a more detained calculation, and there are flight-planning programs that will actually do so. The question is, what do examiners really want to see?
Sincerely,
M. Wilson
Greetings M. Wilson:
Here's my rule of thumb regarding rules of thumb: Use a rule of thumb on anything you desire except fuel burn, otherwise you'll be all thumbs when it comes to calculating the precise amount of fuel in your tanks.
Yes, I know there are several rules of thumb floating around regarding fuel usage and time to climb. The problem is that many of these rules of thumb get a thumbs down for their accuracy. While accuracy may not be an issue when it comes to estimating required descent rates and cloud bases, it nevertheless makes sense to strive for petrol precision with fuel calculations. Here's what I suggest you teach your students.
Have them check the airplane's POH (pilot's operating handbook) for a chart that allows them to compute fuel usage during a climb. Most POHs have such a chart. The Cessna 172, for instance, has a chart titled Time, Fuel and Distance to Climb. This chart allows you to estimate with great precision the time, distance, and fuel required to make a climb to cruise altitude. For example, the chart shows that you'll cover 12 nm in 10 minutes and use 1.9 gallons of fuel as you climb through an altitude difference of 6,000 feet at 60 knots IAS. With this information, as well as any headwind or tailwind component you've calculated, your student can easily estimate his or her arrival time and fuel usage at the first checkpoint.
For instance, suppose that the first checkpoint is 15 miles away. Under a no-wind condition, you only need to compute the time to fly three additional miles at cruise speed to find the ETA at the first checkpoint. If there's a wind involved, so what? These calculations should be child's play for anyone who's passed - or is preparing to take - the private pilot knowledge exam. I can make these calculations in seconds with one hand while using the E6B computer. Typically, however, it often takes two hands and a bit more time when using the standard electronic aviation calculator.
If the Time, Fuel and Distance to Climb chart isn't available for your student's specific airplane, then make one. Do so by determining that particular airplane's average fuel burn rate in a climb and the average rate of climb during climb to cruise altitude. This is how airplane owners come to know their airplane's precise fuel burn. Sure, it will require a few hours of experimentation, but you can do this during the course of training. There's no good reason why you shouldn't create an approximate Time, Fuel and Distance to Climb chart for your student when one isn't available for his or her particular airplane.
What do examiners like to see regarding precision with checkpoint computation? All I can say is that your students can't go wrong if they strive for precision. The above methods of calculation are certainly more precise than the rule of thumb you mentioned.
Consider the following. It's unlikely that your students will create elaborate flight logs for future flights once they are certificated. Nevertheless, your insistence that they use flight logs early in their training will at least force them to think in terms of checkpoints after they become private pilots.
This is also why you should insist on precision when your students compute time and fuel usage during private pilot training. You want to leave them with the impression that precision is important when it comes to knowing the amount of fuel in their tanks. As they strive to become experienced aviators, this type of training will serve them well.
Scary stalls
Dear Rod:
I have a question for you. I am into my second flight lesson, which is stalls. The way my instructor explained it to me seems horrifying. First the nose pitches waaaaay up, then the stall horn activates, then the nose drops waaaaay down. I do not like the way this sounds.
Do you have any advice about how I can expect to feel when I get into a stall? My instructor says it is just like on a roller coaster when it is about to drop. Any suggestions?
Thanks,
Norm
Greetings Norm:
Wow, stalls on your second lesson? No continuing or advanced practice of climbs, turns, descents? No slow flight practice yet? You must be on the accelerated program. I hope this isn't a crash course.
From your description, it sounds like your instructor will also have you throw your hands up over your head and scream as you go "roller coaster-like" over the stall hump. Unfortunately, the situation you describe is one of the main reasons we have trouble keeping people in aviation. In my opinion, we'd never have to worry about increasing student starts in aviation if we could just keep the students we have without scaring some of them off. As flight instructors, we'd be better off if we were just a little more cautious about the words we choose to use during flight training.
First, the airplane's nose doesn't go waaaaay up when entering a stall unless the pilot pulls the controls waaaaay back with waaaaay too much force. Even then, an airplane can stall at any attitude and any airspeed, which means the airplane can stall when the nose is pointed straight down, too. Furthermore, the nose doesn't necessarily drop waaaaay down when the airplane stalls. Geesh, I know combat pilots who'd get scared by listening to stall talk like this.
A more sensitive flight instructor (no, I don't mean one who cries at weddings, either) might choose to talk his or her students though their first stall in such a way that these students barely realized they stalled in the first place.
For instance, this might be done from level flight by reducing the power and gently applying elevator back pressure sufficient to keep the nose just barely above the horizon. As the airplane approaches its critical angle of attack, a stall is surely imminent. At the first sign of wing buffet, however, elevator back pressure is released and the nose gently lowered to just a few inches below the horizon. Power is also applied to accelerate stall recovery. This is an excellent way for an instructor to introduce anyone to a stall.
It's also an introduction that can be done from a power-off descent. In this case, the airplane's nose is held a bit above the normal glide angle until it stalls. Then the nose is lowered a bit below the normal glide angle to reduce the angle of attack below critical. Imagine that, a stall recovery without power. If you didn't know better you'd think glider pilots do the same thing.
Neither of these two introductory stall methods should scare anyone. Once a student is introduced to a stall this way, he or she is less likely to become frightened when practicing more advanced versions of stalls and recoveries.
So, have a chat with your flight instructor and request that you be introduced to stalls by the method described above. It will go a long waaaaay in making the process of learning more fun.
Rod Machado is a flight instructor, author, educator, and speaker. A pilot for 32 years and a CFI for 28, he has flown more than 8,000 hours and owns a Beech A36 Bonanza. Visit his Web site ( www.rodmachado.com ).
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