It was a warm spring day at Flagstaff. The wind was down Runway 21 at 16 knots with gusts to 22. The density altitude at the airport, 7,000 feet above sea level, was 9,000 feet; but that would not be a problem for the lightly loaded A36 Bonanza that taxied away from the FBO a few minutes before noon.
A Cessna 172 took off a little more than a minute after the Bonanza. The Cessna pilot, a 3,000-hour flight instructor and former naval aviator, called the tower to report that he was about to turn crosswind.
“Making my left turn,” he said. “I’ve got the other guy in sight. Is he OK? He is awful low.”
The tower asked the Bonanza pilot whether he needed assistance.
“Yeah,” he replied, “I’m climbing very slowly and staying close to the airport.”
“That boy’s about to get a lesson in density altitude,” the Cessna pilot said. “I don’t understand why he didn’t stay over the interstate, but …”
Thirty seconds later, the Cessna pilot, who had not continued his turn but instead had followed the Bonanza, transmitted, “Tower, we’ve got a plane crash, the guy’s in the ground. I’m gonna circle the area. We’ve got a plane crash. We’ve got fire and smoke.”
The Cessna pilot continued to circle to help rescuers locate the site, which was among a small group of houses in a forest of tall pine trees a few miles southeast of the airport. Witnesses who had seen the Bonanza pass low overhead and heard the crash rushed to the scene and tried to extinguish the fire with handheld fire extinguishers and dirt. The two occupants of the airplane, a physician, 59, and his wife, 54, died in the crash.
Evidently, there had been some sort of problem with the engine. The A36 was several hundred pounds below gross, but even at gross weight it should have climbed out of Flagstaff that day at 700 fpm. According to several witnesses, one of whom was a pilot, the Bonanza’s engine sounded as though it was missing, and it made an irregular popping sound — “audible but not overwhelming” — as it passed low overhead.
Tearing down the engine revealed nothing to explain its failure to deliver the expected power.
Investigators could only speculate. They postulated, without evidence, that the pilot had rotated prematurely and remained “behind the power curve,” unable to climb without first descending to gain speed. Premature rotation typically occurs, however, either when a runway is too short or an airplane is too heavy. But the runway was long and the airplane was light, and there was no reason for the pilot not to use his customary rotation speed.
Since there was no evidence of a mechanical failure, the loss of power could have been due to an incorrect mixture setting, either excessively lean or excessively rich. The NTSB’s analysis favored excessively lean, perhaps because the investigator in charge linked a discolored exhaust valve in a single cylinder to a chronically lean mixture. However, it is difficult to see why the pilot would have made his mixture overly lean, when leaning for a high-altitude takeoff, as recommended by the POH, required consciously seeking and identifying the setting for best power, which is well to the rich side of peak EGT.
An equally plausible explanation might have been a mixture that was too rich. But this, like the other theories, is mere supposition. The wreckage was too badly burned for the positions of the mixture control and the boost-pump selector switch to be determined.
Apart from the mystery of the airplane’s failure to climb, there are two other issues that are perhaps more instructive to think about.
According to the owner of the FBO, the pilot, who had asked him some questions about how to get from Flagstaff to Bryce Canyon, did not seem well prepared for the trip. He was apparently unaware of the Grand Canyon special flight rules area and the Sunny Military Operations Area, both of which lie between Flagstaff and Bryce. Perhaps he was also unaware of the north-south highway that runs right past the departure end of Runway 21. However, the Bonanza actually followed the highway south for a little way before veering eastward.
Several witnesses described the airplane as seeming to bank indecisively back and forth; perhaps the pilot, whose first impulse seems to have been to try to return to the airport, was wavering between turning back and continuing straight ahead, and he simply could not decide what to do. If that was the case, it was unfortunate that his indecision led him farther from the highway.
It’s not always possible, but it’s desirable before takeoff to form some plan of action in case of power loss during the initial climb. A look at a sectional chart may provide useful clues about the locations of roads, bodies of water and obstacles, and the general slope, if any, of the surrounding terrain. In this case, the terrain descended to the south; the Bonanza would have needed to climb just to return to the runway.
From his vantage point 1,500 feet above the ground, the Cessna pilot probably could not tell whether the Bonanza was climbing or descending. He likely assumed that it was climbing, although slowly; he could not have known or expected the Bonanza might actually crash. But in his statement to the NTSB, he expressed regret that he did not explicitly direct the Bonanza pilot toward the highway. “I wish I had piped up on the radio and said, ‘Put it down on the highway. You won’t make it back to the airport.’ But I did not.”
After a disaster occurs, it is common to feel one did not do enough to prevent it. Our knowledge of the outcome distorts our judgment of the preamble, and we chide ourselves for not having recognized what seems obvious in hindsight. In fact, the Cessna pilot had mentioned the highway on the open frequency — a tactful way of calling the other pilot’s attention to it without directly telling him what to do. Either the Bonanza pilot did not register the hint, or he was too startled, flustered and confused to act upon it. At times like this, even simple choices become unexpectedly difficult to make.
