Pilots learn that little problems crop up all the time. Experience tells you which problems are serious and which are mere annoyances. On most flights, a simple problem or two wont threaten the safety of the flight. Even serious problems are within the scope of pilot training.
There are flights, however, when every card dealt plays into the dealers hand. A simple cross-country flight becomes an obstacle course of risk on top of risk, where the prize at the end isnt fame or riches, but mere survival. In this high-stakes game, sometimes you win a little wisdom. Sometimes you dont.
Consider the 18-year-old pilot of a Piper Warrior, who planned a trip one January Sunday for a grievous occasion. He and his passenger were flying from Brainerd, Minn., to Rochester, Minn., to attend a funeral on Monday. The pilot originally planned to fly into nearby Dodge Center Airport, but the weather report indicated fog would make landing there impossible. However the weather reports were clear for two nearby airports, Owatonna about 20 miles to the west and Rochester, about 30 miles to the east.
The passenger called his mother at about 9:15 p.m. and advised her that they would arrive at the Owatonna airport shortly after 11 p.m. She arrived at about 11:10 and waited until about midnight. When the flight did not arrive, she drove into town and called her daughter in law, who advised her that, as far as she knew, plans had not changed.
The mother drove back to the airport and waited another anguished hour. The airport was foggy and there was a light mist falling, but the runway lights and beacon were operating. There was no moon. Once she thought she saw an airplane to the west of the airport, but wasnt sure. Finally she gave up and went home.
In fact, the Warrior didnt depart on the planned 165 nm trip until about 10:30, which would have put it in at about midnight. But even then the flight was far from over.
A witness in Northfield, some 20 miles north of the intended destination, said that he observed a single-engine, low-wing plane resembling the Warrior fly overhead at about 2:30 a.m. The airplane was headed south at an estimated altitude of about 300 feet agl. He said the engine sounded fine, but that visibility was less than a mile with light snow falling. The altitude was very low, he told investigators. [I] wondered why he was flying.
The next morning, a young woman in Faribault, Minn., was on her way to school when she saw a downed airplane by the side of the road. She returned home and notified her brother, a Rice County Deputy. He went to the scene and found the Warrior, with the two occupants lying face-down in the maroon-stained snow.
The evidence suggests that the plane crashed about 4 a.m., more than four hours after it should have reached its destination and more than five hours after takeoff. The weather overnight had been ceilings of 700 feet, visibility 2.5 miles with ground fog. The temperature at the time of the accident was 24 F and the dewpoint was 21.
Despite the long flight, the aircraft apparently did not run out of fuel. Although the tanks were destroyed, the carburetor contained fuel and the engine controls appeared to show a normal cruise configuration. Investigators could find no evidence of a mechanical problem that would have brought the airplane down.
The Plot Thickens
The young pilot had received his private license only five months before the accident. During those five months he had added another 20 hours to his log book, bringing his total to about 75 hours. He had seven hours total time at night and four hours of simulated instrument time.
All the signs were there for continued VFR flight into poor visibility, followed by spatial disorientation and a crash. Cut and dried pilot error. A rookie mistake.
The biggest question that remained, then, was why the pilot apparently droned around for several hours looking for a fog-shrouded airport instead of turning back to his point of origin.
The coroner, however, discovered another twist to the story.
The pilots blood showed about 26 percent carbon monoxide, and the passenger showed about 13 percent. A test of the pilots car, parked at the Brainerd airport, showed no carbon monoxide contamination. The Warriors wreckage, however, pointed to a likely culprit.
The airplanes 26-year-old muffler was found riddled with pinholes and corrosion. The heater shroud had oil baked on its inside surface.
The muffler had flown about 1,200 hours since its installation. Two Piper Service Letters outlined inspection procedures for the exhaust system in general and the muffler specifically. The airplanes logs contained no entries that suggested the advisories had ever been followed.
The muffler also had a repetitive AD for inspections every 50 hours once the time in service exceeded 950 hours. Another AD required that the heater shroud be removed and the exhaust system inspected every 50 hours. Again, no entries in the airplanes logs mentioned compliance with either AD.
The Warrior had passed an annual inspection about two months before the accident. During the inspection, mechanics did not keep a written checklist of the results, but did give investigators a handwritten list of discrepancies found. The list shows 18 squawks and eight upgrades that were being made at the time. The pilot assisted with the annual as an apprentice mechanic.
Some of the squawks were minor, such as warnings that several hoses and seals appeared original and should be replaced. A few ADs were listed, and checked off as the work was completed. Two items, however, were marked with a Df where the others were checked. One was for a landing light seal. Next to that entry, someone wrote next 100 hours or LL change. The other entry stated simply Muffler condition.
The mechanics who performed the annual said the Df referred to the initials of the mechanic who performed the work, despite the fact that none of the mechanics identified as having worked on the annual had those initials. One mechanic said he checked the muffler by removing six screws around the shroud, then looking inside with a mirror and flashlight. He said he did not notice any rust, only a few very small holes at the end of the muffler. He said he did not think they were serious or would cause a problem.
The mechanic who conducted the actual inspection said he completely removed the shroud and inspected the muffler, but did not notice anything unusual, including any holes, corrosion or cracks. He signed off the annual and returned the aircraft to service.
Investigators also discovered that the shroud was incorrectly installed because portions of the metal were missing.
Heavy Duty Chain
If you think of accidents as a chain of misfortunes, as aviators are wont to do, then this was a stout chain indeed. Consider the cast of villains: inexperience, dark night, fog, get-thereitis, the questionable condition of the muffler and, finally, the carbon monoxide.
Had any one of these factors been omitted, the outcome of this flight may have been decidedly different. A little experience would have told him not to go. A moon may have lit up the landscape enough for him to find the runway. A less-pressing reason to go may have led him to postpone the trip. A healthy exhaust system would have prevented the CO poisoning that dulled his mind as he wandered through the night sky.
Those are a lot of maybes, but somehow it always seems to come back to the annual inspection. Df. Deferred? Didnt fix? Dont [mess] with it?
Although there are many uncertainties about the role maintenance played in this accident, the event does underscore the need to stay on top of whats happening to the planes you fly. If you own your plane, make sure the mechanic is clear on the fact that problems should be prevented, not just fixed. If the mechanic assumes that gives him carte blanche to ruin your credit, find another mechanic. It shouldnt take a rocket scientist to realize that a 26-year-old muffler is not to be trusted.
Know the ADs that apply to your airplane and make sure theyre addressed. Read the service letters with your mechanic and decide together whether each one addresses a real safety problem or whether the manufacturer is trying to erect a liability shield.
If youre a renter, insist that the operator give you access to the maintenance records. Many will balk at this, but its your life on the line, and you deserve the right to know what risk youre assuming.
The unfortunate reality in aviation is that it often takes a tragedy to be a wake-up call to the rest of the pilot population. Dont oversleep on this one, or you may end up wishing youd taken up skiing instead.
-by Ken Ibold
