I’ve flown my share of first flights after maintenance. Most went well; some didn’t. My first bad experience involved retrieving a Piper PA-28-181 Archer II from a scheduled inspection. The run-up and takeoff were nominal. Soon after, ATC reported my transponder wasn’t working and gave me identifying vectors before I flew around the Bravo between me and the destination.
Once parked on the ramp, I pulled the mixture to idle cutoff and…nothing happened. I shut it off with the magneto switch (when I should have just turned off the fuel valve). Turned out the transponder’s spike antenna on the belly had been snapped off, and the mixture control linkage wasn’t connected.
Stuff can happen in the typical aircraft maintenance facility. While there are checks and balances to ensure work is correctly performed and documented, it can take only a cellphone call to interrupt the workflow, and things can go off the rails.
As an aircraft owner, I can attest to how demanding it can be to manage its maintenance. It’s different when considering flying an airplane I don’t own, but for different reasons, mainly because I don’t know as much about how it’s been maintained. Logbooks often tell a part of the story, but not all of it.
Ultimately, it’s up to the mechanic who works on and signs off the airplane to verify the work was completed correctly. The pilot likely isn’t trained to evaluate what work was performed or how well it was done. But there are things we can do to verify the work was performed correctly. The sidebar below offers a few suggestions.
In this case, the airplane hadn’t flown in more than a year. The last time it had been aloft, it failed to make full power, and its pilots had trouble climbing out after takeoff. Ironically—or perhaps not—both accident pilots were aboard that flight 13 months earlier.
Mechanics are human. Humans make mistakes. A pilot’s job is to presume someone made a mistake and find it. Here’s an example of why.
Background
On October 21, 2022, at about 1845 Eastern time, a 1970 Beechcraft A24R Sierra 200 was destroyed when it failed to climb after takeoff and collided with a storage building in Keene, New Hampshire. The flight instructor (male, 60) and commercial-rated pilot in the left seat (male, 41) were fatally injured. Visual conditions prevailed.
At about 1844, the airplane took off from Keene’s Dillant/Hopkins Airport (KEEN) Runway 02. Several witnesses (including pilots and a mechanic) who were located on the airport reported the engine did not sound normal, with one reporting that it “never sounded smooth the entire time the airplane was on the runway or while airborne.” After takeoff, the flight continued in a very shallow climb, climbing to between 50 feet and no higher than about 200 feet agl. Several witnesses located northwest of the departure end of the runway reported that the “poor” engine sound continued. A witness about 0.5 nautical mile north-northeast from the runway’s departure end reported hearing “pop pop pop” sounds in quick succession, like backfiring, but did not observe the collision.
Investigation
The airplane impacted a storage building attached to an apartment building about 0.54 nm north-northeast of the runway’s departure end. A post-crash fire ensued, causing extensive damage to the airplane and the structures.
Before the accident flight, the accident airplane last flew on September 4, 2021, over 13 months before the accident flight. On that flight, the airplane performed poorly, forcing the pilot to climb by making “zig zag” turns up a valley until they cleared a ridge before landing uneventfully at the destination airport, KEEN. The airplane’s owner/operator indicated the performance issue during that flight was a plugged fuel injector.
(The right front-seat pilot during the September 4th flight was the accident flight instructor, and a passenger in one of the rear seats was the left-seat pilot during the accident flight.)
The airplane’s last annual inspection was completed two days before the accident flight. A post-maintenance check flight was not performed after the annual inspection; the accident flight was the first flight flown after the annual inspection.
The mechanic who performed the annual inspection reported cleaning the fuel injector nozzles, replacing five spark plugs and re-timing the magnetos. Each cylinder’s differential compression check was greater than 75 psi when checked at 80 psi. The mechanic who performed a full-power post-maintenance engine run earlier on the day of the accident reported the maximum rpm attained was between 2300 and 2375 rpm.
Visual examination of each two-piece fuel injector nozzle revealed none of them had an insert or restrictor installed. Each fuel injector nozzle was flow checked as found in the engine at the accident site, i.e., without an insert or restrictor fitting installed. The testing could not be completed due to excessive leakage from the bleed hole, which stopped when an exemplar insert was installed.
Testing of a four-cylinder engine from the same manufacturer was performed with and without the nozzle insert(s) or restrictor(s) installed. Testing with all inserts or restrictors installed resulted in the greatest power output. With either all or some of the inserts/restrictors removed, reduced power output and fuel leaks resulted.
There was no evidence of pre-impact failure or malfunctions involving the propeller or propeller governor.
Probable Cause
The NTSB determined the probable cause(s) of this accident to include: “Improper maintenance of the fuel injector nozzles and the pilots’ failure to abort the takeoff during the takeoff roll. Contributing to the accident was the mechanic’s decision to return the airplane to service with the engine unable to attain its full rated power.”
Acoustic analysis indicated that the engine was only turning at about 2400 rpm, when it should have been 2700 for full power. The NTSB speculated the mechanic who ran up the engine for the propeller rpm test was satisfied with the result, which would be typical for a fixed-pitch propeller. But this Sierra had a constant-speed prop, and should have been able to reach full power—2700 rpm—in a static test.
There are two things about this accident I really don’t understand. First is that the two pilots were aboard the airplane the last time it was flown and knew from that experience the airplane wasn’t making full power. There’s nothing in the NTSB report indicating the two pilots took any extra precautions for this takeoff. They seemed to accept the owner’s assurance it was a dirty injector but made no real effort at verification. The other thing is the engine should have leaked fuel when it was running. Did no one notice this? Did the mechanic in fact do the run-up or did they pencil-whip it?
Bottom line, though: The pilots didn’t do much in the way of takeoff planning. Witnesses reported it lifted off at midpoint of the 6201-foot-long runway.
