Point Of Diversion 3 — Lessons Learned

Bad things can happen when a pilot flies without understanding the complete situation that surrounds them. Last week we learned from three pilots who did not have complete awareness and because of it, each had an accident on takeoff. Let’s recap…

LESSON #1</strong>
The first pilot was a student flying a Grumann AA-A5 and was unhurt even though his airplane hit trees. The accident investigator wrote a statement of what he thought was the probable cause: The student pilot’s delayed decision to abort the takeoff, resulting in his inability to stop the airplane in the remaining runway. Factors were the pilot’s lack of total flying experience, and the high outside air temperature at the time of the accident.

Critical Point: The temperature at the time of the accident was 100 degrees F. The student must not have considered the fact that extremely high temperatures make the air less “flyable.” High temperatures make the air molecules more sparse (less dense) and when there are fewer molecules the wing does work as well, the propeller has less to grip and pull us forward, and the engine has less air to compress into power.

POD: A POD (point of diversion) took place the moment the pilot taxied onto the runway without allowing for the conditions that were present at that time. When the student faced this takeoff, he must have counted on a regular takeoff, but conditions were not regular. The pilot thought the airplane would act normally, but in reality the airplane could not act normally under those conditions.

The second pilot also asked an airplane to do what the airplane could not do: takeoff while overweight. The accident investigator in this case wrote this as the accident’s probable cause: The pilot’s improper planning/decision, and his attempt to fly the aircraft while it was loaded over its maximum allowable gross weight.

Critical Point: The airplane’s wings can only produce so much lift. For easy comparison, the amount of lift a wing can create is calculated in pounds. In other words, how many pound of force in the “up” direction can the wing generate? Weight is the force in pounds in the “down” direction. If the airplane’s “down” force is greater than its “up” force, the airplane will not fly.

POD: This pilot suffered a POD even before he got in the aircraft. Weight and balance is too often replaced with “Whatever, it worked last time, it’ll work this time.” When a pilot loads the airplane improperly and knowingly or in ignorance attempts to defy one of the laws of physics, the stronger force always wins.

The third pilot took off in Alaska during extremely cold conditions and into frozen precipitation. The Probable Cause: The icing of the induction/intake screen and the pilot’s improper planning/decision by electing to takeoff into suspended snow and ice crystals.

Critical Point: As pilots, we worry about running out of fuel, but what about running out of air? The engine must have both fuel and air to operate and it must be in the proper ratio. This pilot did not realize that the cold temperatures and frozen precipitation in the air could block the flow of air to the engine. Without air, the engine quits just like the flame goes out when you sit a glass upside down over a lit candle. Next time you preflight, I am sure you will check the fuel level – but you must also check the fuel’s companion for combustion: air. Is the air intake dirty, oily, blocked with a bird’s nest?

POD: This pilot experienced a POD when he failed to recognize that air is just as important as fuel. Remember: for every gallon of fuel you burn, you must bring in about 12 “gallons” of air through the intake to go with it.

Understand the concepts of density altitude, airplane weight, and engine operations. These are common topics for pilots, and most pilots know quite a great deal about each. But when pilots fail to apply this knowledge in practice, accidents happen. Learn to police your own thoughts and apply what you have learned to what you see. That means learning to apply knowledge to every situation — not just the one presented in the book or by your instructor — and make informed judgements. Learn to do it or nature will enforce its own laws and pass judgement on you.

Can you see where the pilots in the next two examples went wrong? Can you spot the POD that they missed?

#1 NTSB Report Number: ATL89LA202

The airplane engine experienced a loss of power during final approach, and the airplane subsequently crashed into trees short of the runway. The student pilot was on a local, unsupervised solo flight and had concluded several touch and go landings prior to the power loss. The total flight time of this flight was about one hour. The operator reported that post-crash examination of the airplane revealed no fuel remaining in the fuel tanks. The operator noted that the airplane had been operated a total 4.6 hours since its last refueling. He also noted that the pilot who had flown the airplane on the previous flight reported that he had estimated the tanks were about 1/2 full when he preflighted the airplane prior to this flight.

#2 NTSB Report Number: ATL96LA091

The pilot reported that the fuel gauges were inaccurate, registering less fuel than was actually in the fuel tanks. According to his accident report, the pilot took off with five gallons of fuel in the airplane. He flew to a local airport and made a low pass. He then proceeded to another airfield and made a touch and go landing. The pilot then contacted approach control at his destination for final landing. According to the pilot, traffic was unusually heavy and the flight was vectored in sequence for landing. On final approach, the pilot advised the controller that the engine had quit, due to lack of fuel. Subsequently, the airplane collided with a powerline, then crashed to the ground in a residential area, about one-mile north of the airport. During examination of the wreckage, approximately eight ounces of fuel were found in each fuel tank. The fuel caps were in place, and there was no evidence of fuel leakage from either tank.

Next week see if your evaluation of what went wrong matches the evaluation of the accident investigator.