When you rent a car, you do not receive instructions for operating it, nor are you expected to study the 300-page owner’s manual before turning the key. It is assumed that all cars work similarly, all drivers are familiar with the important controls, and there are few, if any, operating limitations to worry about.
Not so with airplanes. There are much greater differences in the performance, limitations and systems among different models. Some important information is encoded on the instruments; the airspeed indicator, for instance, is a particularly eloquent instructor, brimming with tips on how to handle the machine to which it is attached. Placards provide additional information and warnings deemed important for safety. But you can’t put everything there is to know about an airplane on placards; some of it remains in the POH, and it is, in principle, the duty of the pilot to go there to find it. Experience in one type does not necessarily carry over to others; nor is mastery of a larger, more complex airplane evidence of a general ability to fly smaller, simpler ones.
From time to time an accident occurs because of something the pilot did not know about the airplane or knew but failed to think of. Here is an example. Last summer in Michigan, a pilot perished with his mother, his stepfather and a cousin when the 1976 Cessna 172M in which they were going for a pleasure flight failed to gain altitude after takeoff, mushed and eventually stalled. The pilot, 19, had gotten his private ticket a month earlier, having logged 52 hours, 42 of which were dual instruction, in Cirrus SR20s. (It was possible, but was not confirmed, that he had flown a few hours in a 172 elsewhere.)
They took off from Runway 9L; the wind was 130 degrees at 6 knots. The Cessna climbed to around 150 feet but did not climb any farther. The pilot told the tower, in a calm voice, that he was “a little overweight” and needed to return and land. The tower cleared him to return to the runway or to land on any of the grass areas surrounding it. Over the departure end of the runway, however, the airplane wallowed unsteadily and then dropped to the ground, where it exploded in flames.
One witness reported hearing the engine sputtering and seeing the airplane crabbed 30 degrees as it proceeded down the runway, but the National Transportation Safety Board found no evidence of any mechanical problem. A pilot who was landing on a parallel runway as the 172 took off gave a detailed description of its movements; they did not include a 30-degree sideslip, which is probably a physical impossibility in a 172 anyway. The reason for the failure to climb, investigators found, was quite simple: The flaps were set at 40 degrees, the maximum. Investigators attributed the mistake to the pilot’s lack of familiarity with the aircraft and to the dissimilarity between the flap actuation procedures and protocols of the 172 and the SR20.
The SR20, with a 200 hp engine and a constant-speed propeller, has a gross weight of 3,050 pounds as well as a gross-weight rate of climb slightly superior to the 172’s. In the training role, however, the Cirrus could be a few hundred pounds below gross and climb considerably better. Flaps 20, or half flap, is normally used for takeoff. The Cessna 172M, whose gross weight is only 2,300 pounds, has a 150 hp engine. Its wing area is larger than that of the Cirrus and normally no flap is recommended for takeoff; for a soft or rough field 10 degrees of flap can get the airplane airborne a little sooner. At gross weight, a clean 172M will climb at around 700 fpm.
Although both types have electric flaps, the actuation procedures are different. In the Cirrus, the pilot selects one of three positions — zero, half and full — and the flap moves to that position. Cycling the flap is part of the pretakeoff checklist. In the 172, the pilot runs the flap motor by holding the flap switch up or down until the flap indicator reaches the desired point. A functional check of the flaps is not part of the pretakeoff protocol. At gross weight, a 172M is barely able to climb with full flap; the POH specifically advises against takeoff with more than flaps 10, but that warning is not placarded on the instrument panel where, incidentally, the flap switch and gauge occupy inconspicuous positions. In fact, apart from repeated calls for “Flaps: UP” in several checklists in the POH, the only hint that using more than 10 degrees might cause a problem is the statement, in a brief paragraph on the subject of high-altitude takeoffs, that “flap settings greater than 10 degrees are not approved for takeoff.”
The NTSB’s finding of probable cause attributes the pilot’s “failure to retract the wing flaps before attempting to take off” to lack of familiarity with the airplane. The implication of “failure to retract” — since the airplane would not normally be parked with its flaps down — is that the pilot followed the Cirrus procedure of cycling the flaps to full as part of the preflight check but must then have forgotten to retract them. The NTSB investigators appear not to have interviewed the instructor who checked the pilot out in the rented 172, but from some letters included in the online docket it appears that the young man was conscientious and tried to inform himself about various details of 172 operation. He was aware of the weight issue and intended to limit his fuel load in order to keep the airplane legal. He succeeded; investigators calculated that the Cessna’s weight was a few pounds under gross.
The pilot’s failure to retract the flaps was in all likelihood not due entirely to “lack of familiarity with the airplane make and model,” as the NTSB says. Neither the Cirrus nor the Cessna, nor any other remotely similar airplane, takes off with full flap. If the pilot had been merely using a Cirrus procedure in the Cessna, he would have taken off with half flaps and probably gotten away with it.
A more likely explanation, it seems to me, is a combination of two elements. One is the sort of nervousness and stage fright that a new pilot — or even a new driver — feels when under the scrutiny of other eyes, particularly those of family members. Consider the passenger list: mother, stepfather and a cousin nearly twice his age. The presence of observers whose esteem one values is distracting when one is doing something that has not yet become second nature. The young man had just turned 19, was bound for the Naval Academy, and was showing off his newly acquired pilot’s license. It would be remarkable if he had not felt some performance anxiety.
The other component was an aspect of his very conscientiousness. He had been concerned about flying the Cessna at gross weight; he realized that this would be different from his experience in the more powerful Cirrus. His attention was focused upon weight, and when the airplane failed to climb as expected, he jumped to the conclusion that excess weight must be the cause.
Now, it is noteworthy that the airplane did climb to 150 feet — well out of ground effect — and stay there for a while. It should have been possible to slowly raise the flaps — “bleed them up” — while carefully maintaining speed. Once at half flap the airplane would have begun to accelerate and climb. But the young pilot was thinking about weight, and that idea seems to have eclipsed any thought of the flaps, of whose setting — much drag, little lift — he was most likely completely unaware.
This article is based on the NTSB’s report of the accident and is intended to bring the issues raised to our readers’ attention. It is not intended to judge or to reach any definitive conclusions about the ability or capacity of any person, living or dead, or any aircraft or accessory.