The Drowsy Syrups of the World

In the spring of 2002 a Beech D-45, the civilianized version of the Bonanza-derived T-34 Mentor military trainer, crashed while attempting a landing in gusty conditions at Minden, Louisiana. Both occupants of the tandem two-seat airplane were killed.

The Mentor's owner, a private pilot, had flown over 1,000 hours in it since acquiring it in 1983. He suffered from a benign but gradually progressing condition called essential tremor-excessive involuntary shaking of the head and hands - and the medications he took to control it, Klonopin and Inderal, together with some "unusual behavior" that he had displayed "during operation of an aircraft," had led to his FAA medical certificate being suspended in 1996. In 2000 he had applied again for a medical, reporting that he was now taking only the cholesterol-lowering drug Lipitor. He also stated that he did not suffer from any neurological disorders, though his essential tremor was alluded to in the "Notes" section of the application. The third-class medical certificate was issued, but withdrawn a week later when his blood tests came back with an abnormally elevated glucose level that suggested possible diabetes. He had not subsequently applied for an aviation medical. Despite the pilot's having lost his medical certification, he continued to maintain his airplane and probably to fly it at least occasionally. The engine, which was majored in 1996, had clocked 118.6 hours when the last annual was performed in September 2001. It is unclear how many, if any, of these hours were flown by the owner, but he could have continued to fly as long as he had another pilot aboard.

For a few days before the accident, the airplane had been hangared at Minden; the owner had taken a position at a hospital there. During that time he had made the acquaintance of the airport manager, and they had discussed flying the airplane. The manager held a commercial certificate with an instrument rating; he was also a flight instructor. He had 321 hours, but no experience in the D-45.

Minden has a 5,000-foot asphalt runway running north-south, with a stand of 45-foot trees beginning about 120 yards to the west. There is no control tower. On the day of the accident, a gusty wind was blowing from the east, either at 10 to 20 or at 15 to 25 knots, depending on what part of the accident report you believe. The two pilots took off at three in the afternoon and after performing a series of maneuvers at 2,000 to 3,000 feet above the airport, perhaps to familiarize the airport manager, who was in the back seat, with the feel of the airplane, they re-entered the traffic pattern for a series of touch-and-go landings on Runway 01.

Witnesses on the ground reported that the pilot - which of the two it was is unknown - was "having problems" correcting for the variable right crosswind. On the fourth approach, the airport manager radioed the Unicom operator to "come out and watch [my] landing." The airplane, its flaps fully extended, drifted west of the centerline. The ensuing sequence of events is confusing, but witnesses reported that it stalled, full power was applied, and the airplane pitched up and rolled to the left before diving into the wooded area west of the runway.

No mechanical malfunction was apparent from examination of the wreckage, but the flaps, which witnesses had reported to have been fully extended during the approach, were found in the retracted position. The flaps are electrically operated; it appears that one of the pilots, on initiating the go-around, must have raised the flap switch to the "up" position.

The usual procedure for a crosswind landing is to use no flap, or only a small flap deflection, in order to keep the airplane's speed up and its drag down, and thereby to reduce the proportional influence of the wind. Standard crosswind landing technique involves approaching with the controls coordinated and the airplane's heading adjusted into the wind to eliminate drift. Shortly before touching down, the pilot performs a "de-crab" maneuver to align the airplane with the runway; the upwind wing is lowered and opposite rudder is used to hold heading. For a pilot unaccustomed to the tandem seating of the D-45 with its limited visibility from the aft seat, this might be a difficult maneuver to perform accurately without practice. Normally, the pilot in command (or the student pilot) occupies the front seat. In this case, the pilots' roles were ambiguous; the pilot-owner in the front seat was the de facto instructor, while the instructor pilot in the back seat was the de facto student. At the same time, the back seat pilot, whom the National Transportation Safety Board called "the pilot-rated passenger," was technically the pilot in command, because the front seat pilot did not hold a valid medical certificate.

Autopsies of the pilots disclosed diazepam - Valium - and diazepam metabolites in the owner, as well as two other anti-anxiety medications, oxazepam and

temazepam, which may have helped to control his essential tremor. Propanolol (also known as propranolol) was also found; this is the chemical name of Inderal, another anti-tremor agent. The NTSB subpoenaed the pilot's medical records from his neurologist. They alluded, as recently as the month before the accident, to his regular use of Valium with "minimal side effects … especially considering the doses he is taking," and to his having previously complained of daytime drowsiness.

The NTSB straddled the ambiguities surrounding the actual control of the airplane at the time of the crash. The cause of the accident, it found, was "the [owner-pilot's] failure to maintain aircraft control during a go-around. Contributing factors were [his] impairment due to drugs, the pilot-rated passenger's lack of experience in the airplane and the prevailing gusty crosswind conditions."

The evidence for a causal connection between drugs and any given accident is always circumstantial. The NTSB noted that diazepam would have "substantial adverse effects on judgment, alertness and performance," and that propanolol "may result in dizziness, fatigue and decreased G-tolerance." On the other hand, it does not take superhuman alertness or skill, as a rule, to go around from a balked landing; and, whatever deficits his medications may have produced in the pilot, he had 19 years and 1,000 hours of experience in the airplane to compensate for them. When an accident occurs and the pilot is not found to have any drug, licit or illicit, in his system, the NTSB never expresses astonishment that the mishap could simply have occurred in the normal course of events, because from time to time people make unexpected mistakes and things happen that really shouldn't. If the autopsy finds drugs, on the other hand, they are assumed to be responsible for the accident.

If we simply subtract the Valium and Inderal from this accident, we are left with a fairly classic-looking case of uncertainty about who is in charge. The NTSB blamed the accident on the owner-pilot, presumably because he was the one who was experienced in the airplane and was sitting in front. But it was apparently the back-seater who was actually flying, and who was, incidentally, the certified flight instructor. If the airplane drifted to the left, it was being carried toward the trees; possibly one of the pilots suddenly became aware of that fact and reacted by pulling up too abruptly. Possibly the retraction of the flaps was premature and coincided with a gust from the rear quarter that robbed the airplane of some of its airspeed. Possibly the owner-pilot's medications had something to do with all this, and possibly they did not.

You can search the NTSB's query page (ntsb.gov/ntsb/query.asp) for accident reports containing the word diazepam (to pick one popular drug at random). For the period from the beginning of 2000 to the present, a dozen or so accidents pop up in which diazepam was present in the pilot's remains. As a general rule, however, these pilots did not report on their applications for medical certification that they took any drug whose regular use would have disqualified them from flying. This is to be expected; if they had been honest, and had been grounded, they would not have found their way into the NTSB accident reports.

This article is based solely on the National Transportation Safety Board's report of the accident and is intended to bring the issues raised to the attention of our readers. 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.