Controlled Flight Into Terrain

Background

We all find it difficult to imagine flying an airplane into the ground or an obstacle. As strange as it may seem, it happens way too frequently. According to the FAA, 17% of all general aviation fatalities are a result of Controlled Flight Into Terrain, or "CFIT".  The FAA provides the following definition:  "CFIT occurs when an airworthy aircraft is flown, under the control of a qualified pilot, into terrain (water or obstacles) with inadequate awareness on the part of the pilot of the impending collision." The statistic and the definition were taken from the Advisory Circular, AC61-134 which was prepared to address the problem.

Another FAA production, one of the "Safer Skies" series of DVDs, also addresses CFIT. In it, risk factors which may lead to a CFIT accident are presented. They are omission of an action or an inappropriate action, lack of positional awareness, flight handling, "getthere-itis", and poor professional judgment or airmanship. In this discussion, we will take the first risk factor, omission of an action or an inappropriate action, and see how it contributed to two recent accidents, one IFR and one VFR.

IFR Example

Our IFR example occurred near Ithaca, NY in October of 2005. The pilot of a Mooney struck trees and crashed into a residential neighborhood while attempting to execute a VOR/GPS approach into the Tompkins County Airport in Instrument Meteorological Conditions (IMC). Though dramatic, it had a relatively happy ending with the pilot escaping with only slight injuries and no injuries or serious property damage on the ground.

Miraculously, the airplane made initial contact with the ground in the backyard of one house, traveled between two houses, only slightly nicking one of them, and came to rest inverted in the driveway of the other. Various parts, including one wing were shed along the way.

According to the approach chart, that would have put the airplane 373 ft. above the terrain, or at least 323 ft. above the trees.

The pilot stated, "I can not really explain why I let the airplane descend too low. I felt comfortable with the approach throughout. I simply was too low, too far away from [the] airport." The official probable cause finding of the NTSB is as follows: "The pilot's failure to comply with the published instrument approach procedure, which resulted in an in-flight collision with trees."

VFR Example

Our VFR example occurred near Fullerton, CA in December of 2004 at about 0948 local time. The significance of the time will be evident later. This accident had a very unhappy ending, resulting in two fatalities and the destruction of a major radio transmission tower.  The Cessna 182 was en route to Fullerton on a perfect flying day with clear sky, visibility 10 miles, and the wind out of the north at 5 kts.

The tower controller stated that pilot made contact indicating that he was northwest of the airport. The pilot was cleared for a left base entry for runway 06. The pilot was cleared to land when he was about three miles north of the airport. shortly thereafter, the controller observed an explosion west of the airport and watched as the KFI tower collapsed.

The tower was struck only about fifteen feet from the top. In the IFR accident previously discussed, tragedy was narrowly averted by the airplane's flight path taking it just a few feet from either of the houses that it careened past. In this case, a few feet difference in the flight path, either right, left, or higher, would have avoided the entire accident. But, that wasn't to be so let's take a look at the causal factors and what could have been done to prevent the accident.

During the investigation, questions were raised regarding the actions of the tower controller. Radar was available in the tower and it was being used at the time of the crash. The radio tower was depicted on the radar screen. It was suggested that perhaps the controller contributed to the accident by instructing the pilot to enter a left base leg from his position. This argument has some merit considering that the AIM suggests that pilots enter the traffic pattern on a 45 degree angle. From the position that the pilot was instructed to enter the left base leg, recommended procedures dictated a path very close to the radio tower.

But, a check of the Airport Facility Directory states that the recommended traffic pattern altitude (TPA) for Fullerton is 1100 ft. MSL and the top of the tower was 819 ft. MSL. The tower was located two miles west-northwest of the airport center. The collision occured approximately 300 ft. below TPA. However, since the airplane is usually descending while on base leg, we would expect the airplane to be below TPA. To put all that in perspective, the airplane hit a radio tower when it was about 700 ft. above the ground tow miles from the airport. That is probably a little too low for normal operations, but would not be considered as reckless. It should be noted that the pilot was initially rated in helicopters and had only recently begun to fly airplanes. Helicopters routinely fly lower than airplanes so this altitude would probably seemed rather high to the pilot.

So what caused the collision? It seems to go back to our risk factor "omission of an action or an inappropriate action." The pilot omitted the action of studying the airport  information available and and being familiar with the hazards present. On a clear, sunny day, it sometimes seems unnecessary to determine a safe minimum altitude for operation in the vicinity of an airport.

Certainly the radio tower was quite visible. But, when the pilot turned southeast to enter the base leg, the airplane was headed right into the sun, effectively making the forward visibility near zero.

The lesson to be learned from this is simply that pilots must always research the the hazards in the vicinity of an airport or any other location where low altitude maneuvering is necessary. A minimum safe altitude must be established and followed.

The KFI radio tower before.

In summary, these two accidents would be classified as CFIT, but they are typical of many accidents where a relatively minor oversight, omission of an action, or an inappropriate action has very unfavorable results. Most of these accidents involve pilots with at least moderate levels of experience. These accidents are not necessarily a result of poor training. In our IFR example, the pilot most certainly had been trained in the importance of maintaining MDA until the runway is in sight. He most certainly possessed the flying skill to control the altitude within 50 ft. But still he failed to properly brief the approach in his mind and have a minimum altitude firmly established. In our VFR example, the pilot most certainly knew about the radio tower. He had visited the same airport several times before. He probably failed to take all the precautions one would take on a marginal weather day such as know the height of all the obstacles in the vicinity of the airport and establish a minimum safe altitude in his mind. As pilots we have a responsibility to not only know the proper procedures, but to follow them on each and every aspect of each and every flight