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Vectors For Safety - December 2022

Safety Initiative Update

Consider it!

Time is running out on the half-price offer! Enroll now for our popular Human Factors Ground School-Live for January 2023. As always, registration is limited to facilitate discussion. The course consists of three live sessions on three consecutive Thursdays, Jan. 5, Jan. 12, and Jan. 19 with each session beginning at 7:00 Eastern. Missed sessions can be made up via watching the video. Couse completion is valid for all three FAA Wings credits at the basic level. Click here to for more info and to register. Enter coupon code EARLYHALFOFF during checkout to take advantage of 50% off during early registration until Dec. 10.

Avoid the List!

On November 19, two grandparents were killed in a Winston-Salem, NC crash on their way to visit family for Thanksgiving. Every year we can compile a list of holiday-related GA travel that ends in tragedy. Please make every effort to avoid being part of that list. Please consider viewing "Holiday Travel Hazards." Our recorded webinar examines some of the factors that can increase the risks of holiday travel in general aviation airplanes. Strategies to help mitigate those risks are presented. Several recent accidents are analyzed and discussed. (Note: Watching the video is not valid for FAA Wings credit.)

Sara Update!

As of November 18, granddaughter Sara is a CFI! Next is CFII, ME, and MEI and then on to an aviation career. Grandpa is proud!

Check It Out!

I just launched a new short video series titles, "Old Pilot Tips." Each video in the series will be not more than one minute in length and will focus on a single important topic. Episode #1 focuses on fuel selectors and Episode #2 provides some thoughts on safely switching fuel tanks wile in flight. Check out the videos on my YouTube Channel and don't forget to subscribe while you are there! Videos are also available on the VectorsForSafety website Videos tab.

Take It!

Our newly revised and accredited Checklist Micro-Course. The course is free, courtesy of Avemco Insurance and is valid for 1 credit, advanced knowledge-2 in the Wings program and also for the Avemco Safety Rewards Program. Click here to check it out.

Download It!

The November/December Safety Briefing magazine that is. I think this is a particularly good issue. If you have not seen it yet, down load it here.

Avemco Insurance sponsors Gene Benson
Gene's Blog

Safety After Maintenance

Isn’t automation grand? Robots assemble cars, vacuum our houses, dispense cash from ATM machines, fly around taking photos and videos, land airliners, and much more. They rarely make errors that are not the fault of human programming. Humans are still needed for many tasks such as performing most surgeries, fighting structure fires, driving most cars, installing furnaces, and much more. Humans, on the other hand, are more likely to make errors. In fact, they even have a kind of error named for them, human error.

Maintaining the aircraft we fly is of course one of those tasks for which we require error-prone humans. As a result, many errors are made during aircraft maintenance. Most of these errors are minor. Some are detected before the airplane is released to the customer. Others, also minor, are detected by a pilot before flight is attempted. Others go undetected, but do not pose significant risk to safety. Still others cause serious situations which are detected by pilots in flight and are managed without having an accident or reportable incident. But still others produce dangerous conditions that result in a crash.

I recently asked pilots to share their anecdotal stories of their experiences with maintenance errors. I received enough response to know that maintenance errors are not uncommon. But before we condemn the aircraft maintenance community, let’s realize that the pilot community makes many mistakes also. Like the maintenance folks, most of our errors do not result in catastrophe or even in a bent airplane. We are all human and are more than capable of making errors. But as pilots, we must be diligent in doing as much as possible to detect problems before that first flight after maintenance.

We need to do a “like your life depends on it” preflight inspection. Use your preflight inspection checklist but approach it with the mindset that something is wrong and it is your quest to find it. Never assume that because a system was not the subject of the maintenance performed, it was not disassembled or adjusted in some way. Any drips of liquid, loose wires, or unattached hardware should be cause for alarm. Like any preflight, we should check for free and correct control movement, full and smooth flap movement, full and free trim movement, including rudder trim if applicable, unobstructed fuel and static vents and everything else on the preflight inspection checklist. If practical, have a look at the engine compartment with the cowling removed. Once we are satisfied with the preflight inspection, we should do an engine runup and a few minutes of taxi. Check for correct operation of gyro instruments. Turn on high-draw electrics and make sure the alternator keeps up. Before shutdown, with the throttle at idle, quickly turn the ignition switch to the OFF position and immediately to the BOTH position. The engine should begin to die when in the ignition switch is in the OFF position and quickly come back to life when returned to “BOTH.” This verifies that the P-leads are connected and that the propeller is safe to handle on the ramp.

Now it is time to shut down the engine, depart the airplane, and take a careful look around. There should be no sign of fuel or oil leaks. Also look for any evidence that something, such as an inspection panel, is loose.

Of course, there are many things we cannot check. Is the torque correct on through bolts deep inside the engine case? Incorrect torque on through bolts shows up frequently as a cause of catastrophic engine failure. Yet, it is among the many items we cannot check for ourselves.

Mike Busch of is a recognized expert in the field of general aviation maintenance. He highly recommends a test flight after any significant maintenance, especially after any engine work. Mike states that the first 10 to 20 hours after engine work is when a problem is likely to occur. He stresses that the maintenance test flight must be approached with a test pilot mentality and an expectation of encountering a problem. Some commonsense things apply, such as using a runway long enough to safely abort the takeoff, making the flight in day VFR conditions, and doing it solo. Mike has lots of sound advice and I highly recommend looking at his site’s Resources Page. From there you can find his YouTube channel with hours of free education for pilots and aircraft owners.

As part of my research, I, with the help of my colleague Tom Turner who writes the popular Flying Lessons, part of Mastery Flight Training, Inc., asked pilot to tell us about their experiences with problems after maintenance. I want to thank all those who responded to our request. Due to space considerations, click here to see excerpts from a few of the responses, click here to see the remainder of this article on our media subdomain.

broken image

The following narrative is reprinted from the NASA ASRS database.

A Piper Arrow owner has an engine failure after maintenance.

Narrative: 1

A privately-owned/flown ZZZ-based aircraft used solely by the owner, was brought to us by the owner in late 2015 to conduct some extensive maintenance, including an engine overhaul. The aircraft flew without incident after overhaul. During its annual inspection earlier this year, the owner requested a modification to the engine to replace the existing oil drain plug to a quick drain valve. The mechanic who was trying to find the quick drain valve was unable to locate the part number in our FAA-approved illustrated parts catalog for the Piper Arrow. I instructed him to give an Aviation Parts Center a call because they had been great at helping us find part numbers that are difficult to locate. When the mechanic called he gave him the aircraft tail number, make, model, engine model, and serial number. I overheard the call/conversation by the mechanic. After he got off the phone, he said they are shipping it ground. We received the quick drain valve, but due to work load at the time, we elected not to install the quick drain valve before returning the aircraft to service from the annual inspection. We decided to wait until the first oil change since we were going to change the oil and oil filter after 20 hours of flight since the engine had just been installed on the aircraft after having an overhaul.

In March 2016, the owner flew the aircraft and had just returned from his flight and told me that the aircraft had just reached the 20 hour mark and was ready for its oil change. The mechanic apprentice and I conducted the oil change, cut filter for inspection, installed the quick drain, test ran aircraft on the ground, and returned to service. At the time when the aircraft was returned to service, I believed that the work was done to standard and that the aircraft was safe for flight. The aircraft departed on a local owner-flown flight in March. After departure and near cruising altitude, the aircraft engine quit and the pilot landed on a local highway. The pilot was not injured but the airframe sustained damage due to the gear-up landing.

Based on the on-site inspections by the FAA and additional research conducted by our shop, we believe there were several factors involved in the engine quitting. While we procured the correct quick drain valve based on aircraft/engine make/model/SN, the incorrect valve was shipped and installed in the aircraft. The Aviation Parts Center nor I caught the error. Although the ground run showed no leaks after the new valve was installed, the gear retraction (in flight) may have triggered the loss of oil and the engine quitting. We would strongly recommend that Piper Mandatory Service Bulletin 965 be converted to an Airworthiness Directive.


A Piper Arrow made a gear-up landing on a highway due to an engine failure. The engine failed due to loss of oil because of an incorrect "quick drain" oil plug installed.

Accident Analysis

Accidents discussed in this section are presented in the hope that pilots can learn from the misfortune of others and perhaps avoid an accident. It is easy to read an accident report and dismiss the cause as carelessness or as a dumb mistake. But let's remember that the accident pilot did not get up in the morning and say, "Gee, I think I'll go have an accident today." Nearly all pilots believe that they are safe. Honest introspection frequently reveals that on some occasion, we might have traveled down that same accident path.

I normally do not discuss accidents until a final accident report has been issued by the NTSB. However, since this accident is very much inline with our discussion of crashes after maintenance and since it happened to one of my readers with whom I have had correspondence, I am including it here. Please note that of this writing the accident investigation is still in the preliminary phase and anything reported is subject to change in the final report.

The crash happened about mid-day on October 10, 2021 near Greeneville, South Carolina and involved a Flight Design CTLS. The NTSB preliminary accident report includes the following: "According to the pilot, an annual inspection was conducted at Twin Lakes Airport (S17), Graniteville, South Carolina and the accident flight was his first flight in the airplane after the inspection. He conducted a preflight inspection of the airplane with no anomalies noted and departed for Henderson, North Carolina. About 18 miles south of his destination, the engine oil pressure dropped to zero. The pilot turned towards Greenville Downtown Airport (GMU), Greenville, South Carolina, and declared an emergency. The engine continued to run for about 4 or 5 minutes before it seized. The pilot reported to GMU that he would not be able to reach the airport and turned towards an open clearing before deploying the airplane’s ballistic parachute about 500 ft above ground level (agl). Shortly after deploying the parachute, the airplane floated into pine trees and was suspended about 50 ft agl about 9 miles north of GMU. The pilot climbed out of the side window and was rescued by local authorities."


The NTSB preliminary accident report includes the following: "Postaccident examination of the airplane by a Federal Aviation Administration inspector revealed two engine oil hoses disconnected and substantial damage to the fuselage and left wing."


The pilot deserves great credit here for remaining calm, declaring an emergency, and activating the ballistic chute in a timely manner. He survived with a few cuts and bruises, but the outcome might have been very different, both for him and for someone on the ground had he attempted a forced landing near a populated area.

Per our discussion on crashes after maintenance and assuming that the oil lines were not properly tightened during maintenance, which has not been established by the NTSB, is there anything the pilot could have done to prevent this accident? There was probably nothing visible to reveal the problem. Perhaps an extended, high-power runup followed by another preflight inspection would have produced some evidence of an oil leak, but probably not. Perhaps an maintenance test flight with a few circles around the airport would have caused an oil line to become disconnected allowing a landing at the airport? Probably not given the fact that the crash happened more than 80 miles from the departure airport. Not all maintenance related accidents are preventable by the pilot. When an unplanned event occurs during flight, sometimes the best we can do is to remain calm, resolve to continue flying the airplane, and use all available resources. This pilot appears to have done that. His resources were declaring an emergency and finally activating the ballistic chute. No one, including the pilot, was seriously injured and that is what really matters in the end.

Accident Analysis

Accidents discussed in this section are presented in the hope that pilots can learn from the misfortune of others and perhaps avoid an accident. It is easy to read an accident report and dismiss the cause as carelessness or as a dumb mistake. But let's remember that the accident pilot did not get up in the morning and say, "Gee, I think I'll go have an accident today." Nearly all pilots believe that they are safe. Honest introspection frequently reveals that on some occasion, we might have traveled down that same accident path.

This crash involved a Cessna 182 and occurred in Ohio on October 28, 2020. Neither the pilot nor the passenger were injured but the airplane was substantially damaged. The NTSB accident report includes the following: "The pilot and passenger were on a cross-country flight after maintenance personnel installed new avionics in the airplane. While at cruise altitude, the engine began to knock and vibrate and subsequently the engine lost all power. The pilot was unable to maintain altitude or reach an airport and landed the airplane in a field. The airplane overran the field and impacted trees; the wings and fuselage sustained substantial damage."


NTSB Photo

The accident report continues: "The wreckage was examined, and a plastic cap was found installed on the engine crankcase breather port; the engine crankcase seal was found dislodged. Oil was found on the underside of the engine compartment and cowling. The blocked breather port likely allowed excessive pressure to build up inside the engine and resulted in the dislodged crankcase seal and a loss of oil."

NTSB Photo

And still more from the NTSB accident report: "The investigation determined the mechanic who installed the avionics on the airplane also performed maintenance on the engine, which was outside of the repair station’s operations specifications. The mechanic did not have technical data for the work performed on the engine, did not document the work performed, and did not remove the plastic cap from the crankcase breather port following the installation of avionics. The accident is consistent with a total loss of engine power due to oil starvation as a result of improper maintenance."


NTSB Photo

The NTSB the probable cause(s) of this accident to be: "Improper maintenance that resulted in a blocked crankcase breather port and a subsequent total loss of engine power."

The pilot stated the following recommendation in the Pilot-Operator-Report submitted to the NTSB: "As an operator of an aircraft returning to service all initial flight, regardless of the type of service will be performed under the following conditions;

1) Daylight VFR hours

2) VFR

3) Within distance of the airport"

As we saw in an earlier accident analysis, a maintenance test flight in the vicinity of the airport will not reveal all impending problems, but in this case it most most likely have prevented this accident. Again, we credit the pilot for continuing to fly the airplane, maintain control, and avoid loss-of-life or serious injury.

Click here to download the accident report from the NTSB website.

Accident Analysis

Accidents discussed in this section are presented in the hope that pilots can learn from the misfortune of others and perhaps avoid an accident. It is easy to read an accident report and dismiss the cause as carelessness or as a dumb mistake. But let's remember that the accident pilot did not get up in the morning and say, "Gee, I think I'll go have an accident today." Nearly all pilots believe that they are safe. Honest introspection frequently reveals that on some occasion, we might have traveled down that same accident path.


NTSB Photo

This unfortunate crash happened on the first flight after a lengthy restoration. It involved a Piper Tri-Pacer and happened In Cortland, New York on July 13, 2020. The crash resulted in just one minor injury. The NTSB accident report includes the following: "The pilot was performing a post-maintenance test flight after a "lengthy restoration" of the airplane had been completed by a mechanic, who accompanied him on the flight. After takeoff, the airplane did not respond in accordance with the pilot’s control inputs, so he elected to immediately land the airplane. The airplane impacted the ground off the departure end of the runway, which resulted in substantial damage to the wings and fuselage. Post-accident examination of the airplane revealed that the aileron control cables had been rigged opposite of the proper orientation prescribed in the airplane’s illustrated parts catalog. Both the pilot and the mechanic stated that when they conducted flight control checks prior to the flight, they confirmed deflection of the ailerons, but that they each failed to confirm that the aileron deflection corresponded correctly to the input at the control yoke."

Warren Idaho Airport

NTSB Photo

The NTSB probable cause finding states, "The mechanic’s incorrect rigging of the aileron control cables, which resulted in a reversal of aileron control inputs applied by the pilot during the takeoff. Also causal was the mechanic’s inadequate post-maintenance inspection and the pilot's inadequate preflight inspection and before takeoff check, which failed to detect the misrigging"

There is not much to say about this accident except I believe we were all taught to check "free and correct" control movement before takeoff. I always taught my students to put their thumb up as they gripped the control yoke. When moving the ailerons with the yoke, their "up" thumb should point to the "up" aileron. It is also necessary to verify correct elevator movement. It is sometimes difficult to crank your neck around to see the elevator from in a control position, but the check is essential. If your airplane makes it extremely difficult or impossible to see the elevator from inside the airplane, just make sure to check it during the preflight inspection.

Click here to download the accident report from the NTSB website.

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