N24CVCessna 172N · 1977

Hawaiian Airlines flight 70 (HAL70), N2165HA, an Airbus A321, and a Textron Aviation, Inc. C172N, N24CV, were involved in a near mid air collision (NMAC) over the point where runway 30 and the final approach path for runway 26L intersect at Long Beach (Daugherty Field) Airport (LGB).

At the time of the incident, the local control 1 (LC1), local assist, and ground control positions were combined to the LC1 position in the LGB air traffic control tower and staffed by a single certified professional controller. According to ATC transcripts and a post-- event interview, the LC1 controller turned N24CV on a base leg to runway 26L and cleared N24CV to land on 26L when the aircraft was approximately one mile from the runway. About this same time, the LC1 controller also cleared HAL70 to land on runway 30, when the flight was on a four-mile final. The LC1 controller did not realize that N24CV continued another half mile before starting their base turn, an event which led to both aircraft arriving at the airport at nearly the same time. In the three minutes leading to the incident, the LC1 controller received multiple calls on the ground control frequency from aircraft requesting push-back. He also initiated a call to the Traffic Management Unit (TMU) to request a release for another aircraft. These events distracted the LC1 controller from the local control operation at the time of the incident. This duty prioritization was not consistent with guidance contained in FAA Order JO 7110.65AA, Air Traffic Control, 2-1-1, ATC Service and 2-10-3, Tower Team Position Responsibilities.

The controller in charge (CIC) stated in the post event interview that he heard the LC1 controller calling TMU for the release and said he should have made the call instead, and this was a failure on his part. This would have allowed the LC1 controller to concentrate on traffic. The CIC also stated he was not actively monitoring the LC1 controller frequencies and stated he should have been a second set of eyes for the LC1 controller. This was not consistent with guidance contained in the LGB7110.3G SOP, Chapter 3-1-1, Clearance Delivery, Chapter 7-1-1, Front Line Manger/Controller in Charge and 7-2-1, subsection f.

On February 13, 2010, about 2015 central standard time, a Cessna model 172N, N24CV, piloted by a commercial pilot, was substantially damaged during a forced landing following a loss of engine power near Genoa City, Wisconsin. The personal cross-country flight was being conducted under 14 Code of Federal Regulations Part 91 without a flight plan. Night visual meteorological conditions prevailed. The pilot sustained minor injuries. The flight departed Aurora Municipal Airport (ARR), Aurora, Illinois, about 1945, with an intended destination of Austin Straubel International Airport (GRB), Green Bay, Wisconsin.

The pilot stated that during cruise flight he heard a “loud metallic clicking” sound, followed by a “bang” and a vibration. He noted that a few seconds later there was another “bang” and the propeller stopped rotating. He subsequently executed a forced landing to a corn field. The airplane sustained damage to the firewall, nose landing gear, and wings.

A post-accident examination of the engine revealed crankcase fractures in the area of the #3 and #4 cylinders. The engine sump contained approximately 5 quarts of oil at the time of the exam. The oil filter contained metallic fragments. Teardown examination of the engine revealed that the #3 and #4 connecting rod bolts had failed. All four bolts (two common to each connecting rod) failed above the threads, in the shank portion of the bolts. Two of the bolt fragments included the corresponding nuts; however, they were backed off to the end of the bolts. These bolt fragments appeared to have separated from the #3 connecting rod. The remaining two nuts had separated from their corresponding rod bolts. One of the nuts was deformed and scarred consistent with mechanical damage. The other was fragmented.

The remaining two sets of connecting rod bolts appeared intact. However, the nuts securing the #1 connecting rod bolts were loosened by applying minimal torque from a wrench, and the nuts securing the #2 connecting rod bolts were finger tight. The #2 connecting rod and cap were not mated, but were separated approximately 1/8 inch.

Metallurgical examination of the failed connecting rod bolts revealed features consistent with overstress failure. No evidence of a fatigue fracture was observed on any of the fracture surfaces.

Maintenance records indicated that the engine was overhauled on January 12, 2010. It was subsequently installed on the accident airplane on January 28, 2010, at a recording tachometer time of 419.5 hours. The records noted three engine oil changes since overhaul. The most recent oil change was completed on February 11, 2010, at 48.4 hours operation since overhaul. The recording tachometer indicated 487.8 hours (68.3 hours since overhaul) at the time of the post-accident examination.

Documentation provided by the engine manufacturer noted that the connecting rod nuts should be tightened to 480 inch-pounds at the time of installation.

Overhaul records included a Build Up Check Sheet. The sheet included a line item entitled “Rod Nuts Torqued & Safetied.” For this line item, initials had been placed under both the “Technician” and the “Inspector” columns.

A representative of the overhaul facility stated that all connecting rod bolts are replaced and installed as new bolts on overhauled engines. He added that rod bolts are procured directly from the engine manufacturer and not from any third-party manufacturers.