Aviation Accident Summaries

Aviation Accident Summary MIA07LA076

Fort Lauderdale, FL, USA

Aircraft #1

N4946R

Piper PA-46-350P

Analysis

The pilot reported that he confirmed all landing gears were down and locked before landing. After a reported normal touchdown, the airplane started veering to the left. He applied right rudder input but the airplane traveled off the runway onto grass, and collided with a runway light. The nose landing gear collapsed and the airplane came to rest upright. Examination of the airplane following recovery revealed the right two (2) piece foot was fractured at the nose landing gear actuator attach location. NTSB examination of the right foot revealed evidence of fatigue, which covered a 90-degree arc and approximately 55 percent of the .07 inch wall thickness of the foot. Service Bulletin (SB) 1103B, which is not mandatory for the operator of the accident aircraft and had not been complied with, calls for repetitive inspections of the engine mount for cracks in the area where the fatigue crack was located.

Factual Information

"THIS CASE WAS MODIFIED APRIL 16, 2008." On April 16, 2007, about 1337 eastern daylight time, a Piper PA-46-350P, N4946R, registered to Lizard Group, experienced collapse of the nose landing gear during the landing roll at Fort Lauderdale Executive Airport (KFXE), Fort Lauderdale, Florida. Visual meteorological conditions prevailed at the time and a visual flight rules (VFR) flight plan was filed for the 14 Code of Federal Regulations (CFR) Part 91 personal flight from Treasure Cay International Airport, Treasure Cay, Great Abaco Island, Bahamas, to FXE. The airplane was substantially damaged and the private-rated pilot and one passenger were not injured. The flight originated about 1215, from Treasure Cay International Airport. The pilot stated that when the flight was approximately 25 miles from the destination airport, he listened to the automated terminal information service (ATIS) which indicated the wind was from 310 degrees at 12 or 14 knots. The flight continued to the destination and after establishing contact with the KFXE air traffic control tower (ATCT), he was cleared to land on runway 31. He turned onto final approach for runway 31, and confirmed all landing gears were down and locked. He maintained approximately 85-87 knots on final, and landed with two notches of flaps extended. The landing at the "numbers" was smooth, and during the landing roll, the airplane started veering to the left. He applied right rudder to correct but was unsuccessful. The airplane continued uncontrolled to the left off the runway onto grass and collided with a runway light. The nose of the airplane then went down and the propeller contacted the ground. After coming to rest, he secured the airplane then he and the passenger evacuated. Examination of the airplane following recovery by an FAA airworthiness inspector revealed the right foot of the engine mount was fractured at the nose gear actuator attach location. Damage to the firewall and left wing were noted. The airplane was equipped with a two (2) piece foot style engine mount P/N 89137-41. Sections of the engine mount were submitted to the NTSB Materials Laboratory located in Washington, DC. The results of the examination revealed the mount was painted black in the area of both nose actuator attach feet, indicating non compliance with The New Piper Aircraft, Inc., Service Bulletin No. 1103B. No cracks were noted in the weld joint for the left attachment foot and support tubes, but the right attachment foot was separated. The fracture surface was covered by an oxide layer, and the fracture at the forward edge had smooth crack arrest markings on multiple planes consistent with fatigue cracking from multiple origins. The fatigue cracking initiated along the edge of the weld joining the right attachment foot to the two forward tubes in the assembly. The fatigue cracking was evident over an arc of approximately 90 degrees, and at its deepest penetration propagated through approximately 55 percent of the estimated .07 inch wall thickness of the foot. The New Piper Aircraft, Inc., prepared Service Bulletin (SB) Nos. 1103B, dated November 25, 2003, which is not mandatory for 14 CFR Part 91 operations, but is applicable to the accident aircraft by make, model, and serial number. The SB occurred because of previous occurrences involving engine mount cracks in the area of the nose gear actuator attach feet, and specified repetitive inspections each 100 hours time in service or annual inspection, whichever occurs first, to identify cracks in the specified areas of the engine mount. Compliance with the SB required removal of paint for inspection, followed by application of a corrosion inhibitor in the area where the paint was removed. The airplane was manufactured in 1997, had accumulated 923 hours since manufacture at the time of the accident, and was last inspected in accordance with an annual inspection on May 1, 2006.

Probable Cause and Findings

The inadequate design of the engine mount by the manufacturer, resulting in collapse of the nose landing gear.

 

Source: NTSB Aviation Accident Database

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