Simulating Emergencies

Practice of technique on your home computer flight simulator may enhance real-world skills.

0

Given all the time that homebuilders invest in completing their projects, its sometimes surprising how little time is spent preparing for their first flights. There are ways to initiate this process, even before one sets foot in the cockpit, thanks to sophisticated flight simulators that allow users to create homebuilt-type aircraft and situations one would never hope to experience during actual flight.

Proof of the value of flight simulator training is found in aviation accident data. Over the last several years NTSB statistics reflect that in a million trips, there are 700 times more fatalities involving general aviation planes than airliners. (Note: According to the recent studies, Experimental/Amateur-Built aircraft have a slightly higher accident rate than the GA fleet, but that rate is dropping.) Why the disparity between GA and airliners? A number of differences between the two modes of flying may suggest some answers.

Commercial captains re-train every six months, while private pilots have only a biannual check every 24 months.

Airline pilots average about 900 hours per year. The FAA reports that GA pilots average 70 hours per year, and pilots of homebuilt planes fly only 35 hours per year on average.

Airshow coverage sponsor:

Airlines have two pilots in the cockpit, while flying solo is common in general aviation.

The result is that GA pilots are not as prepared to handle emergencies as are their commercial counterparts. The regular flight simulation training that commercial pilots complete helps maintain proficiency. The main idea is to allow pilots to practice how to handle emergency procedures that they may never encounter in the air. It is impractical to try to simulate most equipment failures during actual flight, but it is extremely useful to be able to do so on the ground under controlled conditions. Most GA pilots do not have this luxury, but now some flight simulators can come close to providing the same kind of training that commercial pilots practice.

Simulating Failure

The most popular flight simulators, Microsoft and X-Plane from Laminar Research, have the capability to simulate certain types of failures. Both programs can simulate loss of any of the basic six panel instruments (airspeed, artificial horizon, altitude, turn coordinator, heading or directional gyro, and vertical speed). Any of the several types of radios can cease functioning. Several things can go wrong with the engine system including fires and fuel leaks. The new FS-X from Microsoft has more failure options than does the previous version, Flight Simulator 2004.

Versions of X-Plane are being used to control several FAA-approved training devices and have the ability to simulate a much wider variety of aircraft failures than those triggered by an assortment of events controlled by the instructor. As a matter of fact, using X-Plane, more than 300 potential causes of accidents can be invoked. These features are carried over to the version of X-Plane that is available for private individuals.

I made a study of a couple of months of NTSB reports to find the main causes of accidents. By far, most crashes are caused by pilot error. Lets forget about the ones that involve only running off the end of the runway, failing to negotiate a good crosswind landing, or flying into IMC. These can be simulated also, but lets concentrate on the problems that arise in the air and are a complete surprise to the pilot. Of those remaining, here is the rough distribution:

Fuel exhaustion or lack of carb heat: 40%

Miscellaneous parts of the plane failing: 30%

Mechanical engine failures: 25%

Instrument failures: 5%

While the first category may properly be related directly to pilot error, I include it here because it can be simulated to occur at unexpected times. Failures of various parts of the plane are usually due to poor maintenance, structural damage or fatigue, as are the engine failures. Although loss of an instrument accounts for a relatively small fraction of the accidents, it is one of the issues that the professional simulation companies emphasize in their training, and the simulators handle it well.

Microsofts simulators have a nice feature that allows the program to select which items will fail. Under each tab you can select how many randomly selected items from each category will fail at randomly selected times bounded by time limits you specify. For instance, you can ask for two instruments to fail between 4 and 5 minutes and then one system to go out between 1 and 3 minutes. This might result in the pitot tube failing at 2.1 minutes, losing the airspeed indicator at 4.2, and the artificial horizon at 4.8. Using this process you would never know which item would go bad or when. An interesting point is that there are sometimes two instruments of the same type in the list, say, two altimeters as there would be on some larger planes. The random failure mode may select an instrument that is not on the plane you are flying.

Under the NAVAIDs tab, X-Plane shows all of the nav radio stations within the local area, which is a rectangle 3 longitude by 2 latitude. Any of these VORs, DMEs, etc. can be set to stop working when the airplane reaches a certain speed, altitude or elapsed time, in the same way that instrument and mechanical failures are specified.

The Equipment tabs allow for failure of rudder, ailerons, elevator and flaps in either or both directions. Using the Flying Surfaces page, individual parts of wings, empennage, and struts can fall off of the plane completely.

Try It Out

The results of flying without control of rudder, ailerons, or elevator are predictable, but they can be simulated well. Loss of elevator to control pitch means that you must use trim, throttle and flaps, assuming that they are still working. If the rudder jams you can do a fairly good job using just the ailerons, although turns will be slightly uncoordinated. On the other hand, if the aileron control is lost, extremely uncoordinated turns result with only the rudder available. Incidentally, in the simulators, if a control surface stops working it returns to the neutral position. In X-Plane, if you have specified that the ailerons fail when trying to turn left, they will be centered if you try a left turn but will work properly for right banks.

Inactive instruments are more important in IFR flying than in VFR. In VFR if the attitude indicator is gone, you can use the real horizon, which you should be doing anyway. Loss of the altimeter can be tolerated if you keep the wings level and keep one eye on the vertical speed indicator and the other on the ground. Similarly, an experienced pilot who cant read airspeed can judge it by the feel of the controls and the sound of the wind and the engine. With your simulator, fail some of these instruments and try a bit of cross-country and a few landings. Instructors cover instruments in actual flight training and examination. True, you cant see the instrument, but in using the simulators you can still see the dials, and it takes a while to notice that they are not behaving properly. This is more like the actual situation.

A Real-World Simulation

Heres a real case described in an Internet newsletter recently. A Learjet 36 was flying off the coast of San Diego. After joining up with another plane and doing a cross-under maneuver, the pilot lost sight of the other ship due to sun glare. When normal sight was recovered he discovered he was in a 70 bank and 50 nose down. The pilot reduced power, leveled the wings, and returned to the airport where it was discovered that the right elevator was missing and the left one was damaged. It must have been a midair collision, but the report did not go into that much detail.

I tried to replicate this situation with the simulators. The Microsoft version comes with a Lear 45, and I downloaded from http://www.x-plane.org/ a Lear 35 created by Shade Tree Micro Aviation. These folks do a remarkable job of matching the appearance, panel, specs and performance of a wide range of airplanes not included in the X-Plane stock “hangar.” While Flight Simulator 2004 will not fail flying or control surfaces, FS-X will fail the entire elevator. X-Plane will fail pitch-up or pitch-down control, or you can remove the left or right horizontal stabilizers completely.

With X-Plane I opted to eliminate the right stabilizer and see if I could still fly back to base. I forced the ship into the unusual attitude and then triggered the failure using a button on my joystick. This simulated emergency was probably more serious than the actual Learjet event, because not only was pitch control compromised, but pitch stability suffered with half of the stabilizer missing. Still, I was able to handle the plane reasonably well and get it back on the ground.

At http://www.strangemilitary.com  you can find the story and pictures of an Israeli fighter that lost a wing in a collision and was still able to make it back to land. You can also use your favorite Internet search engine to look for “Grob SPn Crash” to see what happened when some control surface design changes were tested.

Simulating with Homebuilts

Although not many homebuilt and vintage aircraft models come with the simulator packages, third party experts have made models of many, and these are available free or for a small fee. You can actually create your own, but this is easier with X-Plane than it is with the Microsoft products. X-Planes flight model is based on the shape of the plane, while virtually all other simulators use empirically gathered tables of data. I downloaded a Cozy Mark IV designed by Curt Boyll from http://www.X-plane.org and failed part of the right wing with disastrous results.

Another plane from X-plane.org is the Kitfox, modeled by Michel Verheughe and based on the one he owns and flies. After determining that the maximum lift-to-drag ratio was just over 11:1 with the flaperons extended, I placed the plane over the fjord near Verheughes home in Norway. At 3000 feet and about 6 miles from ENFB (Oslo Fornebu), I disabled the engine and glided to a landing only to find another X-Plane hazard: a flock of birds. Verheughe later informed me that I would have had a great deal of trouble landing at ENFB because it was closed in 1998, and buildings occupy the space where the runways once were. Its worth noting that almost all fuel exhaustion accidents reported by the NTSB are the result of the pilot not finding a suitable landing place.

Where to Get Simulators

Information about FSX can be found at www.microsoft.com/games/flightsimulatorx/  where you can download a free demo version. It has only a few planes, 12 airports in the West Indies, and no failure capability. The full product sells in stores or from Internet vendors for $40 to $70. The Microsoft Windows operating system is required.

Go to www.x-plane.org  for facts about the X-plane simulator and a free full functioning download. The only restriction for the demonstration is that the joystick control cuts out after 6 minutes if you have not purchased the product. For only $49 or $69 (depending upon how much world scenery is desired) a pilot with a computer can practice both VFR and IFR emergencies. X-Plane runs on Windows, Macintosh or Linux operating systems, and both of these simulators now require DVD capability on your computer.

LEAVE A REPLY

Please enter your comment!
Please enter your name here

This site uses Akismet to reduce spam. Learn how your comment data is processed.