Flying Between a Rock and a Hard Place

Andy, 83, had built the airplane with help from his friend Barry, 38, a commercial SMEL pilot with a little less than 1,000 hours. The airplane was completed in 2021, and Andy logged some of the 40 hours of “Phase 1” flight testing required for the airplane to be licensed as an experimental. He then moved to another state, leaving the airplane behind. In 2023, having lost his medical and desiring to sell the airplane, he arranged with Barry to complete the Phase 1 flying. Barry was joined by Chuck, 52, also a commercial SMEL pilot with 1,355 hours, who would take on some of the flying.

Between them, Barry and Chuck had already put 14 hours on the airplane, bringing its total flight hours to 22, when, on a clear, sunny April day, Barry made a short pattern flight, then landed and moved to the right seat. Chuck took the left seat. They taxied to Runway 35, where surveillance video recorded the airplane beginning a takeoff roll, slowing to a stop, back-taxiing, and then executing a normal takeoff. (Barry would later tell investigators that although the first takeoff appeared to have been aborted, it wasn’t; the engine “never ran rough.”) 

Everything remained normal until, at 400 feet, the engine partially lost power. Chuck made an immediate left 180-degree turn. A four-lane divided highway ran parallel to the runway, some 400 feet west of it. Chuck flew along the highway on what amounted to a close-in downwind leg. Both pilots adjusted fuel pumps, throttle and mixture, trying to troubleshoot the engine problem. Nothing worked. The airplane was slowly losing altitude. By the time they were abeam the south end of the runway they were at treetop level, too low to attempt the 180-degree turn back to the runway.

Now a new problem confronted them. An overpass crossed the highway a short distance ahead, and, to compound their bad luck, a semitruck was stopped under it. Just beyond the overpass, power lines crossed the highway, barely higher than the overpass itself.

As is often the case with accident victims, Barry could not remember the last moments before impact. He thought Chuck tried to thread the narrow gap between the overpass and the wires, but a witness on the highway described the airplane banking steeply to the left, wings nearly vertical. It struck the overpass, fell to the embankment on its northeast side, and burst into flames. Motorists stopped to help and extricated the seriously injured Barry from the burning airplane. Chuck died in the wreckage.

National Transportation Safety Board (NTSB) investigators tore down the engine in search of the reason for the loss of power. They found that the spark plugs in two of the four cylinders were severely damaged and would sustain a spark only at low cylinder pressures, that is, at low power settings. They attributed the damage to a previous episode of preignition or detonation, either of which can be caused by excessively high temperatures or by fuel of excessively low octane.

The engine handbook stated in one place that automotive fuel of 89 or higher octane should be used and in another that if auto fuel of 90 octane or higher were not available, 100LL could be used. For storage, however, different rules applied: The engine should never be stored for more than three months with automotive fuel in its fuel pump and other plumbing; the approved fuel for long-term storage was 100LL.

Andy, the owner-builder, reported that he had “felt comfortable” using 87 octane auto fuel during the engine’s initial hours of operation two years before the accident, because it was a “small car engine.” He said, furthermore, that during the two years of inactivity—the engine was started and run from time to time, without difficulty—the tank and engine had contained automotive fuel. Barry and Chuck, on the other hand, used 93 octane auto fuel during their 14 hours of flying. The NTSB concluded that the damage to the spark plugs must have occurred, or begun, at some time in the past, presumably when the engine was being run on 87 octane fuel.

In its finding of the probable cause of the accident, the NTSB cited the “owner/builder’s inappropriate use of a lower grade fuel than that required by the airplane and engine operations manual…” A contributing factor was the “pilots’ decision to continue flight at a low altitude following a partial loss of engine power instead of performing an immediate precautionary landing…” 

In its narrative of the event, the NTSB noted that it was likely the fact that the loss of power was partial, not complete, “exacerbated the confusion and indecision by both pilots on whether an immediate precautionary landing should be made.” Instead, “they overflew more than 4,000 feet of a multilane highway with a wide grass median.”

In an unusual epilogue to its accident report, the NTSB acknowledged the difficulty pilots encounter when making decisions in those emergencies—whether mechanical or related to weather, low fuel, being lost, and so on—in which the threat is uncertain or ambiguous. Quoting a 2013 publication of its Australian counterpart, the agency noted that “partial engine power loss presents a more complex scenario to the pilot than complete engine power loss. Following a complete engine failure, a forced landing is inevitable, whereas in a partial power loss, pilots are faced with making a difficult decision whether to continue flight or to make an immediate [precautionary] landing.”

Procedures for dealing with complete engine failure are drilled into pilots from the very outset of their training. But it is impossible to train for every scenario in which pilots must weigh the uncertainties of a dynamic threat (like will the engine continue as it is or will it get worse) against the risk of damaging the airplane or, sometimes, much more trivial inconveniences like missing an appointment or being stuck at a strange airport without an easy way to get home.

In some kinds of emergencies human beings, not just pilots, may unconsciously make use of optimism to stave off paralysis or panic. When this optimism enables a soldier to dash through a hail of bullets and toss a grenade into an enemy machine gun nest, it is called “heroism.” 

People who fear flying think pilots are all irrational optimists, but we know that we are coldly rational beings who weigh risk and reward precisely and anticipate future events with insight and discernment—until we aren’t, and don’t. And then the best rule of thumb is: Expect the worst, and act accordingly.

This column first appeared in the January Issue 954 of the FLYING print edition.