Friday, 24 March 2017
A further article on the subject of spins, quoted from MUROC EAA CHAPTER 1000/Larry Wright (June 1993)
“This may be a big "so what?" for all the "test pilot types", but to those of us who got our license the "old fashioned way," it may be of interest.
In an attempt at currency prior to flying my newly built Lancair 360, I decided to enrol in an Emergency Manoeuvre Course at Santa Paula. The course was taught in a Super Decathlon (180 HP, C/S prop), a very stable, fun platform, or as I now affectionately call her, "The Death-A-Con."
Back in 1976 when I started my commercial rating, instructors were still teaching spin and unusual attitude recovery training, so I figured this would be a nice refresher and a piece of cake ……. wrong! I had never done fully developed spins and had no idea how elevator, aileron, and power accelerated the spin if used at the wrong time or out of sequence.
During one of many fully developed spins, while dropping out of the sky at 7000 feet a minute, at a spin rate of less than one second per turn, and waiting for Joe (my instructor) to tell me, "Okay, that's enough, recover", I saw his reflection in the canopy, hands above his head, screaming like a teenager on an E-ticket ride a Disney Land - what a job!
Then there's the crossover spin - a nice gentle manoeuvre which reminds you that you haven't neutralised the rudder on recovery, by snapping the spin back in the opposite direction at twice the speed - a real fun ride! Now that I'm completely disoriented, Joe tells me "You're doing a fine job, but now I'd like you to anticipate your recovery 180 degrees and recover on a heading of ..…." --– oh yeah, you bet!
After three days of fun flying and confidence building, it turns out the acronym to remember is PARE:
P - Power to idle, flaps up
A - Ailerons neutralised
R - Full rudder, opposite direction
E - Elevator forward of neutral, or aft depending on whether or not you're inverted
During the 1980's NASA published several research papers on the stall, spin, and recovery characteristics of typical general aviation airplanes. An analysis of the data collected during the NASA research identified important considerations about spin recovery methods.
The most poignant observation was that no recovery control input was identified which would always stop the spin. The only 100% guaranteed solution is to prevent the spin before it occurs.
This is accomplished by dealing with roll and yaw appropriately near and above the critical angle of attack. NASA research has shown that the PARE recovery technique is the most effective method of spin recovery, and found that the published aircraft manual spin recovery procedures may not recover an aircraft from developed spin modes.
Other than being a little green around the gills on the drive home, it was a great experience, and I highly recommend such a course to anyone who has not had this type of training. The ground school is excellent, the flying fun, and most importantly, it may save your life someday!”
Thursday, 23 March 2017
Acknowledgements: FAA P-8740-36
The private pilot is master of his or her own destiny, but perhaps the coldest hard fact of all in our world is that proficiency can be linked directly to your financial resources. With fuel and maintenance costs continuing their upward spiral, the cost of general aviation flying grows higher and higher. Spare cash is something we seem to have less of these days, and many necessities compete for it which means much less is left over for private flying.
So does the private pilot really need to fly a lot to maintain proficiency? General aviation airplanes are relatively simple creatures, but it would be foolish to believe that an airplane can’t kill you. It can and it does, as accident statistics point out each year. So, what are we general aviators to do, faced as we are with limited funds and, in many areas of the world, limited good weather in which to fly?
What you must do is to fly smarter, and you can do several things to make the best use of the time you fly. Below are some of those things, but the list is by no means complete; feel free to expand it as you see fit.
· Read the Aircraft Owner’s Manual (POH). Inside you will find all sorts of good information about the aircraft. There are important sections on landing irregularities, crosswind landings, and the stall characteristics of the particular aircraft you will fly. This section will include stall speed for various aircraft configurations and angles of bank, particularly those most used when you fly traffic patterns and landing approaches. It is a good idea to commit the speeds to memory, but if yours is not so good write the speeds down on a note card for ready reference when you fly. You can review the speeds just before you enter the traffic area. Stalling can be extremely hazardous at the low altitudes of the traffic pattern and can place you in a situation from which you cannot recover before hitting the ground. You should read and thoroughly understand the emergency procedures and operating limitations of the aircraft, which are designed to help you safely recover the aircraft when it performs less than advertised. The manual allows you to ponder the manufacturer’s recommendations while you are safe and sound on the ground. If questions arise, it is much better that they arise on the ground than in the air.
· Get out your Logbook. Having read the owner’s manual you now know things you never knew before, and you can’t wait to take off. But take a few minutes to further analyse your proficiency, which is an individual thing. When was the last time you flew? What manoeuvres did you accomplish? Are you embarking on a journey with passengers? There is nothing worse than not being in complete command of every situation when you have an audience watching. If it has been awhile since you last flew, you might consider a flight with an instructor. Nothing major - maybe just a few trips around the pattern - but it can be well worth it. The instructor will ensure that you are flying “by the book,” and if you have developed some bad habits will demonstrate the right way to do things. That is tough to do solo.
· Proficiency Flying Practice. Maybe you decide that a solo flight is more appropriate, but instead of just droning around doing air reconnaissance, take a little time to practice a few stalls here, a steep turn there. You will be surprised at how little time it takes. When you come back to the traffic pattern for landing, practice those short and soft field patterns and landings instead. Try to get in some crosswind practice. Maybe there are some airfields in your local area where a crosswind prevails. This practice will be beneficial when that cold front moves in and the winds kick up. It is also great practice for going cross country to a strange field when you are not exactly familiar with the surroundings or wind patterns. Cross-country flying introduces more variables to go wrong, and you must be prepared. The longer it has been since you flew cross country, the more preparation you need to do. Make sure that you know everything there is to know about your aircraft, the route of flight, and the en-route weather.
· Weather. Weather is an important factor. It is the primary cause of many GA accidents which would have been avoided if the pilot had just turned around and returned home. Often the pilot didn’t have the instrument rating to fly in bad weather, but continued anyway. Clouds make it tough to see mountains and other obstructions. They also contribute to carburettor icing and reduced aircraft performance. So take a good hard look at the weather while you are still on the ground. Consider alternative routes of flight, or delay the trip a day or two until the weather gets better. Consider the field pressure altitude of your intended destination, as a high density altitude can drastically reduce your aircraft performance. If not accomplished properly, take-off and subsequent climb out of ground effect may be impossible. The winds can do interesting things in high altitude areas - from creating turbulence on finals to gusty crosswinds in the flare. If it has been a while since you flew in a similar environment, then postpone the trip until fair weather prevails. Meanwhile, when the winds kick up at your home field call your friendly CFI and get some good crosswind experience.
· Survival. Pack a survival kit in case you have an unexpected forced landing. The items that you choose to include are up to you, but it is a good idea to include water, something energy-producing to eat and, most importantly, some type of first aid.
· Watch for Traffic. So now you’re ready to go, but there’s one more planning factor to remember: know where the major traffic congestion will occur (that is, other airport traffic patterns, airways, navigation aids, and so on). It is great to know all that we have discussed so far, but it can mean nothing if you get too close to another aviator. Be especially watchful and courteous while in the traffic pattern at non-towered or UNICOM fields, as there is nobody else available to watch out for you.
· Professionalism. You must decide what proficiency means to you but remember, you are a pilot-in-command, and so have total responsibility for your fellow aviators, your passengers, and yourself.
So in an era in which cost is a limiting factor in the decision to fly, the above should show you how to get the most out of the money you spend. Put them all together and you have a method for flying smarter, and therefore safer. Give it a try.
Acknowledgements: FAA Advisory Circular 60-22
The Circular explains that ADM is a systematic approach to the mental process used by all involved in aviation to consistently determine the best course of action for a given set of circumstances. It has the following elements:
· Perceive: Information affecting the outcome of a flight is all around you. How you perceive and manage that flow of information will have an effect on each and every flight.
· Process: The second step is to process the information that you perceived.
· Perform: How you perform will be based on the perceiving and processing you did. At the most basic level, you perform in one of two ways: action or inaction. In the perform step, you need to eliminate or at least mitigate any hazard and risk that you perceived and processed.
· Evaluate: The relative success or failure of the flight may hinge on how well you have perceived, processed, and performed in the ADM process. Question your judgment and your action (or inaction) at every step, and then start the 3-P process all over again. The ADM process should not stop until your airplane is parked, shut down, and securely tied down.
Experience, education, and intuition enable us to fill in “gaps” in information received through our five senses. You may not have heard exactly every single word of the ground controller’s taxi instructions, but your expectation helps you fill in the missing words. The problem, of course, is that you might fill in the gaps incorrectly.
Suppose you are in a rented airplane with a scratchy radio, and you have passengers on board who are chatting among themselves. You are tired, but the airport is your home base, so you know exactly what that taxi clearance from your parking spot to the active runway is likely to be. The bad radios and the noise from your passengers cause you to miss a few words of the ground controller’s instructions. Your brain is expecting a certain sequence, so it automatically fills in the missing words. Today, however, the ground controller gave you different instructions, which you “heard” as the normal taxi clearance.
The problem is clear, and it escalates at each step of the ADM process: because you perceived incorrectly, you process & evaluate the taxi clearance and judge it to be “routine,” even though it is not. The mistake becomes greater, and possibly more dangerous, when you perform on the basis of the incorrect information.
The example above begins with a perceptual error in which you simply do not see, hear, or notice a particular piece of information. Human beings are also vulnerable to procedural errors, such as when you correctly perceive and mentally process the controller’s instruction to change to a new radio frequency, but you enter it incorrectly in the radio itself. Forgetting to lower the landing gear is another example of a procedural error.
There are also decisional errors, such as when a pilot elects to continue VFR flight into IMC when neither pilot nor aircraft are equipped for it. Errors in how you perceive and process information can also lead to decisional errors, which in turn affect your performance. Other factors that play a part in decisional error include:
• Framing the alternatives: alternatives can be “framed” in positive terms to support a higher risk decision; e.g. “I know that the weather at my destination is marginal, but I can get there so much faster in the airplane than I can in the car.” But framing in negative terms can help bring a much-needed touch of reality into the ADM process; e.g. “If I find that I cannot land at my destination, I will be stuck at another airport, which would make me late for this appointment.”
• Judgmental heuristics: This term simply means that we sometimes jump to a conclusion too quickly without considering all available or relevant) input.
• Bias: There are several types of bias at play in human decision-making processes. One is confirmation bias, which is the human tendency to look for information to confirm a decision already made, perhaps erroneously as in the taxi clearance example above.
• Expertise, training, experience: Two pilots faced with the same situation will very likely make different decisions, based on past experience and training. In the taxi clearance example, a pilot who is new to a particular airport has no experience with local procedures and, thus, has no preconceived ideas about what the clearance “should” be. That pilot’s lack of experience with the airport can lead to a very different perception of the situation than that of the pilot whose aircraft is based there.
A realistic evaluation of each situation on the basis of ADM should result in a simple “go or no-go” decision, or if already in flight, a “continue or discontinue” decision.
Acknowledgements: FAA Safety Briefings/James Williams
You’ve dutifully downloaded your weather briefing, called Flight Service with a few questions, and filed a flight plan. Now what?
Concerns are not limited to the weather: They also involve the aircraft and the pilot. So, there are other things that should affect your decision making.
Personal minimums should change depending on the environment. If it’s your home airport, you are more likely to have less restrictive minimums because it is familiar - you know where the rocks are.
Wind is a key weather factor, but that really depends on how much of a crosswind is present. A good question is this: What runways are available? In the case of a take-off, you are limited to the runway (or runways) at the departure airport. But, you may have nearby alternatives at your destination. A 15-knot quartering tailwind on one runway could be a headwind on another.
Another question should be what approaches are available. This means both at your departure point (in case you have to turn round and come back in a hurry) and destination, again considering alternates for that destination. If you have multiple instrument landing systems (ILS), you might be more comfortable with less-restrictive minimums than if there were just a lone non-directional beacon (NDB) approach within 50 miles of your destination or departure.
There is another important factor - technology. GPS has not made it to every aircraft yet. If you don’t have GPS, you don’t have as many options. Moreover, if you don’t have a WAAS- (wide area augmentation system) capable GPS receiver, you don’t have access to all the new WAAS approaches.
Another consideration arises from the recent loss of an Intelsat WAAS satellite, one of only two existing at the time. What if WAAS isn’t available? Satellite losses are uncommon, but not impossible. With an extremely limited supply of satellites and the long replacement lead time, services could be compromised. WAAS is more sensitive to this issue, but even basic GPS has only a limited number of spares in orbit. You can’t control these factors, but you should be aware of them. So make sure your old-fashioned nav skills remain an option.
The Bottom Line
This is hardly a comprehensive list of the decision-making factors to consider; rather, it is more of a starting point. The idea is to weigh these and all other factors and balance the risks, wherever possible eliminating or mitigating as much risk as you can.
- · Can you switch destination airports for one with more approaches or better weather?
- · Can you find a route that has more possible diversion airports along the way than the first one your planning software produced?
So Take a good look at your proposed flight and ask: Is there anything I can do to make it safer?
Wednesday, 8 March 2017
Acknowledgements: AIR FACTS (Abridged from an article by Richard Collins)
There should be no mystery…
On the NTSB’s 2017-2018 most wanted list of transportation safety improvements: “From 2008 to 2014, nearly 48 percent of fatal fixed-wing GA accidents in the United States resulted from pilots losing control of their aircraft in flight.”
The sad thing is that this has been forever true. The low altitude, low speed loss of control has always dominated and this was often dismissed with the comment: “He ran out of airspeed and ideas at the same time ………...”
Do pilots know enough about spins?
Spins used to be part of the private pilot training syllabus, but even after the requirement was dropped most instructors included spin demonstrations before first solo and spin training before stalls solo; because students could accidentally spin while practicing stalls and they needed to know how to recover. In 1953, precision spins were a requirement for an instructor. They were done three ways: straight ahead, out of the bottom of a turn, and out of the top of a turn. The spin out of the top was the most difficult.
· Most pilots usually spin to the left, and out of the bottom of left turns I used about 45 degrees of bank, slowed to the stall in the turn and at the stall gave it full left rudder and full right aileron.
· Out of the top, the same left turn, the same slowing, but a different technique approaching the stall. The stick was brought back smartly as full right rudder was applied. Any other way, and the airplane just wallowed into the spin. I didn’t use full opposite aileron because it didn’t seem a natural thing to do.
In the early 1950s we knew the airplane would spin and we knew how to spin and recover, but we really didn’t know why the airplane would spin. We did know that it took stalling and yawing to make the airplane spin and that the corkscrew motion was caused by the angle of attack on the bottom wing being greater than that of the top (outside) wing. What a lot of pilots didn’t know was that in some airplanes you could get enough adverse yaw out of just the ailerons to cause an airplane to spin. Most pilots thought it took full rudder.
When an airplane is spinning it is stalled, so the airspeed is stable just below the stalling speed. Some airplanes will fly out of a spin and into a spiral, with the airspeed building. This needs to be noted quickly and a recovery started from the dive. When spinning, the nose of some airplanes seems to be quite low, others even lower. Some NASA research found that in a steep (nose-down) spin the angle of attack is 20 to 30 degrees. That is not too far from the stalling angle, which averages about 18, and what this means is that the airplane should recover quickly. In a moderately steep spin it is 30 to 45 degrees which would make recovery slower, and in a flat spin the angle of attack is from 65 to 90 degrees. Flat spins are unrecoverable without a spin chute.
Is your aircraft spin-certified?
The Cessna 172 is approved for spins when operated in the Utility Category. Piper certified at least one model of the Cherokee for spins, to be competitive with Cessna trainers, and designed the Tomahawk to have more active spin characteristics than the Cessna 150/152. Cautionary note: The location of the airplane’s centre of gravity is quite important. The further aft it is, the easier the airplane is to spin but recovery is more difficult. With the CG too far aft, recovery will be impossible. The Cessna P210 has a certified aft CG limit of 52 inches, but most have had to put the limit at 50 inches (in learning this at least two airplanes were lost in unrecoverable spins).
How much altitude is lost in a spin?
Lighter wing loading means a lower stalling speed and correspondingly less altitude loss in a spin. The loss in an accidental spin would include loss in the departure from controlled flight and as the airplane entered the spin. Then loss in the time to recognize what happened, then the loss when breaking the spin, then the loss recovering from the dive after the spin. I’ve seen numbers on this ranging from 1,000 feet to 1,500 feet for airplanes in the PA-28/172 class. What that means is that if you stall below that altitude, all those stalls you practiced at altitude, and any spins you have done up high, won’t do you any good. In the spin itself, each turn might account for 400 to 500 feet of loss but again, the entry and recovery have to be considered. When an airplane departs controlled flight and crashes, witnesses on the ground often say “it wobbled and then rolled over and dived into the ground”. If it had been a little higher they would have probably seen the spin start to develop before it hit the ground.
So should we? …..
I always enjoyed spins and think that all pilots would benefit from an exposure to them. That’s the best way to learn that with enough altitude in the right kind of airplane they are fun and relatively benign. But without enough altitude they are a really quick way to snuff out your lights!