Thirsting for Fuel

Fuel system contaminated by drilled-out rivet heads grounds experimental


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


The pilot of a single-engine amateur-built aircraft was at 2,400 feet when he experienced a partial engine failure. Shortly thereafter, the engine became erratic, and then failed completely. The pilot landed in a soybean field.

Investigation disclosed two drilled out rivet heads lodged in the fuel line that had apparently caused fuel starvation and engine stoppage. The aircraft had been in service for approximately three years.

Although the source of the rivet heads is unknown, they may have inadvertently fallen into the open fuel tank filler during construction or maintenance activity. The investigator recommends that experimental aircraft builders consider installing a finger screen at the outlet of the fuel tank to catch and retain debris before it enters the fuel line.

Periodic inspection and cleaning of the finger screen may eliminate debris from the tank, preventing it from clogging the fuel line.

American Champ 7-, 8-, and 11-Series
Rudder Control

A Champion 7KCAB lost rudder control and departed the runway.An investigation determined that the rudder pulley assembly, located in the baggage compartment, was missing the pulley guard. The rudder cable dislodged from the pulley, relieving cable tension, and resulted in a loss of rudder control. Further investigation revealed numerous Service Difficulty Reports that indicated these and other control-system pulleys might seize, causing the control cables to deteriorate and become unserviceable. The majority of the SDRs also reported frayed flap-control cables running over the upper pulleys located in the wing root.The maintenance manual requires a 100-hour inspection of the control system. Inspectors performing annual/100-hour inspections need to ensure the aircraft is being operated in accordance with an approved type design and place special emphasis in the critical fatigue areas of the control system as established in AC 43.13-1B.

Beech P35 Bonanza
Broken Landing Gear Bushing

The landing gear motor seized. Investigation revealed the bushings at the handle end of the worm drive shaft were severely worn and had broken. The locknut had backed off enough to allow the worm gear shaft to move enough to cause the worm gear to bind. The electric gear motor locked up and the emergency gear extension was rendered inoperative as well.

Beech V35 Bonanza
Sheared Fuel Pump Drive Shaft

The engine quit during takeoff and the airplane was damaged.Investigation revealed the drive shaft for the engine-driven fuel pump had sheared, due to a small piece of wire jamming the rotor and vane. Tracing the foreign object to its source revealed the low pressure fuel pump had failed internally at some point and the fragments had contaminated the fuel system. The injector pump on the airplane had recently been repaired due to the damage caused by the fuel pump failure.

Bellanca 14-19-3
Elevator Trim Inoperative

The pilot reported the elevator trim tab became progressively tight and hard to use until it finally became inoperative. The technician found the part containing the movable trim tab is encased in a tight tube and is difficult to access because its between the cockpit headliner and the outer skin. The original lubricant had congealed within the tube.

Cessna 172M
Failed Main Gear Inner Tube

During a preflight inspection, the pilot noticed the right main tire was flat.The wheel assembly was removed and the tube was found to have two quarter-inch tears about seven inches apart on the outboard center seam. There was no evidence of foreign material inside the tire that could have caused the damage.The failed tube and four previous tubes were sent to Michelin for inspection.

Cessna 180
Corroded Gear Leg

During a scheduled inspection, the outer gear leg bracket for the left main gear was found to be severely corroded.The corrosion, which caused severe exfoliation, may have come from engine exhaust. The outside cover was not sealed.

Cessna 210 Centurion
Improper Propeller Blade Angles

After installing a new McCauley propeller under STC SA00920CH, technicians discovered the airplane would only run up to 2,300 static RPM rather than the specified 2,600 RPM.Upon investigation, they discovered the blades low end stops had been incorrectly set and returned the propeller to McCauley for correction. An error in the manufacturers engineering approval system was blamed for allowing the propeller to be shipped with improper blade angles.

Cessna P210N Pressurized Centurion
Main Landing Gear Support

During an inspection, the technician discovered the left and right main landing gear down-lock support shell bumpers had debonded. The bumper edges had curled over preventing the main gear strut from making full-down travel. This condition prevented the main landing gears from properly locking.

Cessna 310Q
Cracked Nose Steering Bellcrank

During an inspection, the technician found the nose gear steering bellcrank cracked along its radius in several locations.The technician noted the new bellcrank is of heavier construction.

Grob G120A
Failed Aileron

During a scheduled inspection at 640 hours total time, the technician noticed a strange sound coming from the ailerons.Inspection revealed the bearing on the left aileron system was coming apart. This may represent a design flaw, given the nature of the lever assembly and the amount of use it gets.

Maule M5-235C
Worn Elevator Control

During a scheduled inspection, the technician discovered a broken strand in the elevator down cable at the forward bellcrank. The problem was found while complying the Maule service bulletin No. 64.

Maule MX7-180
Faulty Ceconite Covering

The 3-inch seam tapes could be stripped off the full length of the airplanes fuselage by holding it lightly and walking away from the aircraft. The tape on the empennage were found hanging to the ground.Inspection revealed poor dope penetration and adhesion. In addition, the paint was very brittle and did not appear to contain any elastic additive.

Mooney M20J
Cracked Engine Case

Tracking an oil leak, the technician discovered a crack in the engine case near the propeller.The crack was unrepairable. The engine had 689 hours since overhaul, and at the time of overhaul the stock 2-blade propeller was replaced with a 3-blade prop in accordance with an STC.

Mooney M20J
Loose Magneto

The aircraft suffered an engine failure after takeoff, and it was damaged in a gear-up landing.Inspection revealed the magneto was disengaged from the accessory case and all the mounting hardware was missing. The magnetos had last been inspected 180 hours earlier and an oil change had been done three months prior to the accident.

Piper PA-28-140 Cherokee
Failed Exhaust Valve

The aircraft suffered a sudden loss of power and was landed on a road.Inspection revealed the No. 3 cylinder had lost about 75 percent of its exhaust valve face, which traveled through the induction system and contaminated other cylinders. Both plugs in the No. 1 cylinder were crushed and showed no gap. One plug in the No. 2 cylinder had no gap. The engine was replaced, and monitoring showed inadequate cooling to the No. 3 cylinder, perhaps because of faulty baffling. Temperatures in excess of 420 degrees may have shortened the life of the valve.

Piper PA-32-300 Lance
Conflicting Engine Specs

The engine data plate calls for magneto timing to be 20 degrees BTC and the airframe manual stipulates 25 degrees BTC.There are several Lycoming service bulletins regarding engine damage from incorrect timing. Indications are that Piper will change the airframe service manual to reflect Lycoming specifications.

Piper PA-44-180 Seminole
Nose Gear Trunnion

During a takeoff roll and when the aircraft was at about 79 knots, the pilot heard a loud pop and saw a piece of the nose gear fly off the aircraft. He aborted the takeoff. While steering the aircraft back to the ramp, he noticed a difference in the steering.During an inspection, the technician discovered that the lower rear section of the nose landing gear trunnion assembly had broken off. When the trunnion assembly separated, it caused the shimmy dampener shaft to shear and bent the bracket on the shimmy dampener body.

Piper PA-46-310P Malibu
Wing Flap Control

The pilot reported that the aircraft rolled when he selected flaps down.The technician inspected the system and found the left flap bellcrank was broken. The failed part was previously inspected in accordance with Piper Service Bulletin 1062. At the time of the inspection, the aircraft was in compliance with the S/B.The breakage was located in the shaft area of the bellcrank, which was not included in the S/B.

Cessna Prop Planes
Fuel, Oil & Hydraulic Hoses May Be Suspect

The FAA issued Airworthiness Directive (AD) 97-01-13 on certain Cessna Models 100, 200, 300, and 400 series airplanes that were equipped with fuel, oil, and hydraulic hoses shipped from Cessna Parts Distribution between March 28, 1995, and June 28, 1996.Subsequent to the issuance of AD 97-01-13, the FAA became aware that suspect hoses may have been installed on additional 200 and 300 series airplanes. The FAA initially planned to supersede AD 97-01-13 by the issuance of additional regulatory action. However, it has been determined that enough time has elapsed since the suspect hoses were shipped by Cessna that routine maintenance should have encouraged the replacement of any suspect hoses that might still be in the fleet or available from spares support facilities in the field. Therefore, the FAA is merely alerting owners, operators, and repair facilities that any remaining S51-10 hoses shipped by Cessna between March 1995, and June 1996 – and possibly installed between March 1995 and February 1997 – should by now be removed from service.


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