Squawk Box

The following information is derived from the FAAs Service Difficulty Reports and Aviation Maintenance Alerts.

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A recent fatal accident of a single-engine aircraft involved the apparent separation of the tailpipe assembly from the turbocharger, which allowed hot exhaust gases to be expelled into the engine compartment.

The pilot reported smoke and fire in the cockpit before the aircraft crashed short of the airport, killing both aboard. The NTSB investigation is targeting an exhaust clamp failure due to fatigue cracks found in the turbocharger to tailpipe clamp. A review of the FAA Service Difficulty Report (SDR) database reveals similar incidents involving this clamp as…

The following information is derived from the FAAs Service Difficulty Reports and Aviation Maintenance Alerts. Click here to view “Flight Control Hardware.”

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During an aircraft accident investigation, an investigator discovered that the starter and the generator 6-gauge wires had numerous lateral splits in the wire insulation. The accident was not related to the defective wire insulation.

Splitting of the wire insulation appears as small, fine dark scratches on the outer covering of the wires and runs lengthwise along the wire. In some cases, the wire insulation splitting has penetrated the covering and exposed the center elec…

The following information is derived from the FAAs Service Difficulty Reports and Aviation Maintenance Alerts.

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Control cables are a critical component of most aircraft flight control systems. The cables are usually manufactured from carbon steel or stainless steel and are lubricated during the manufacturing process.

Both types are susceptible to the effects of corrosion, especially if the lubrication is wiped away by fairleads, stuck pulleys, or is oxidized away over long time periods. Moisture accelerates the process.

The FAA has received reports of corrosion in Cessna 172 aileron control cables in the area at the top of the rear doorpost. Corrosion is most likely i…

The pilot of an M20J noticed sloppy aileron response and observed the right aileron vibrating and not responding to control inputs. The pilot landed safely.

Technicians found the right control link rod assembly had cracked at a factory weld and then through the tubing weld. The break along the weld showed signs of age, while the break in the tubing looked more recent.

There was no indication that the ailerons had been subject to abuse, and the technician noticed that the replacement part was identical except that reinforcing gussets had been added at both 90-degree corners in the link.

Another incident, also in an M20J, had the same characteristics, leading the FAA to issue AD 98-…

When visiting a parachute jump zone airport, an FAA Aviation Safety Inspector discovered the operator was using K1 kerosene to fuel its turbine-powered aircraft.

K1, sold for home heating use, does not meet the American Society for Testing and Materials standards for aviation turbine-engine fuel. It also does not meet FAA requirements specified in aircraft type certificates.

Using such unapproved fuel creates a situation in which the airplanes performance may not be predictable. Although the kerosene may work for a long time in routine operations, quality control is not nearly as stringent, increasing the possibility that the airplane will be filled with bad fuel.

ASTM D-3699-98 an…

Reports several months ago of a tailwheel spring clip coming off of an Aeronca has lead to a spate of reports of similar problems on different makes of taildraggers. Many mechanics encourage operators to safety-wire the retention clips.

An amateur-built Thorpe T-18, for example, suffered substantial damage while landing on a rough runway surface. The aircraft had just been completed and had been test flown at an airport with a paved runway.

The two test pilots then flew back to the home airport, which had a rough landing surface, and the tailwheel bounced hard. The spring retention clip rotated and came off of one of the tiller springs. The pilot applied brakes, but the other tiller s…

The following information is derived from the FAAs Service Difficulty Reports and Aviation Maintenance Alerts. Click here to view “Airworthiness Directives.”

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The FAA has issued a Special Airworthiness Information Bulletin addressing Textron Lycoming piston plug wear. The bulletin aims to help identify abnormally worn piston pin plugs and describes appropriate inspection/maintenance actions.

Lycoming engines have plugs that center the piston pin in the cylinder, which ensures that the piston is centered within the cylinder barrel. The plugs, by design, experience some wear on the plug face, which contacts the cylinder barrel. This…

The following information is derived from the FAAs Service Difficulty Reports and Aviation Maintenance Alerts. Click here to view “Airworthiness Directives.”

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The FAAs Aircraft Certification Office in Atlanta has received reports of problems with oil filters manufactured by Champion. The problems include collapsed elements, rubber gasket material inside the filter canister, and other one-time events. The reports were serious enough for the manufacturer and the FAA to launch an investigation, which revealed that the collapsed elements were caused by the engine oil bypass valve that is installed in some Textron Lycoming engines.

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The following information is derived from the FAAs Service Difficulty Reports and Aviation Maintenance Alerts. Click here to view “Airworthiness Directives.”

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An FAA avionics inspector in the Scottsdale, Ariz., FSDO reported that he has found the ELT remote switch circuits to be defective on two separate new Cessna 172s.

The Pointer 3000-11 model ELTs were both factory installed as original equipment by Cessna. An investigation by the manufacturer determined that the internal fuse had failed, but the manufacturer claimed the problem had been traced to Cessnas post-production test procedure several years ago.

The problem was fi…

The following information is derived from the FAAs Service Difficulty Reports and Aviation Maintenance Alerts. Click here to view “Airworthiness Directives.”

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Fuel bladders in a variety of aircraft may be substandard.

The FAAs Manufacturing Inspection Office in Fort Worth says unapproved fuel bladders were sold and repaired by Duraflex Fuel Cells Corp. and Fuel Cells Maintenance Inc., both of Little Rock, Ark., for use in Twin Commanders, Raytheon Beech 65 and 90 series, Cessna 300 and 400 series, Piper PA-23s and PA-24s, and possibly other aircraft as well.

The FAA says the production and repair of these fuel cells do not m…