# NTSB CEN10IA554: Diamond Aircraft Ind DA 20-C1, N409AM, Bloomington, IL, August 26, 2010 - Type: NTSB incident investigation - Classification: Incident · No injuries · Incident investigation · Final report - Date: August 26, 2010 - Place: Bloomington, IL - Coordinates: 40.476943, -88.915832 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=40.4769&lon=-88.9158&mi=10 - Phase of flight: [Prior to flight](https://openairdocs.org/ntsb-phases/100) (OpenAirDocs' grouping) - Defining event: [Prior to flight: Sys/Comp malf/fail (non-power)](https://openairdocs.org/ntsb-events/330) - Highest injury: No injuries - Injuries: 1 uninjured - Status: Completed, report May 16, 2011 - Report: Approved by Office Director - NTSB office: Central Region - Parties: Transportation Safety Board of Canada, Diamond Aircraft Industries Inc., Federal Aviation Administration - NTSB case key (mKey): 77382 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=CEN10IA554 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/77382/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=77382 - Page: https://openairdocs.org/ntsb/CEN10IA554 ## Probable cause The cracked nose landing gear fork assembly found during the preflight inspection. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Landing gear system: nose/tail landing gear](https://openairdocs.org/ntsb-findings/01023220): Aircraft › Aircraft systems · Failure (probable cause); cases with it: [Diamond Aircraft Ind DA20-C1, 3 cases](https://openairdocs.org/ntsb-findings/01023220/cases.md?model=2990001), [All aircraft, 185 cases](https://openairdocs.org/ntsb-findings/01023220/cases.md) - [Landing gear system: nose/tail landing gear](https://openairdocs.org/ntsb-findings/01023220): Aircraft › Aircraft systems · Design (probable cause); cases with it: [Diamond Aircraft Ind DA20-C1, 3 cases](https://openairdocs.org/ntsb-findings/01023220/cases.md?model=2990001), [All aircraft, 185 cases](https://openairdocs.org/ntsb-findings/01023220/cases.md) - [Safety programs: adequacy of safety program](https://openairdocs.org/ntsb-findings/04035015): Organizational issues › Support/oversight/monitoring · FAA/Regulator; cases with it: [Diamond Aircraft Ind DA20-C1, 2 cases](https://openairdocs.org/ntsb-findings/04035015/cases.md?model=2990001), [All aircraft, 24 cases](https://openairdocs.org/ntsb-findings/04035015/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Prior to flight: Sys/Comp malf/fail (non-power)](https://openairdocs.org/ntsb-events/330) (defining event); cases with it: [Diamond Aircraft Ind DA20-C1, 2 cases](https://openairdocs.org/ntsb-events/330/sequence.md?model=2990001), [All aircraft, 994 cases](https://openairdocs.org/ntsb-events/330/sequence.md) ## Analysis A student pilot found a cracked nose landing gear (NLG) fork, which was the third cracked fork the operator reported in the previous 17 months. A Federal Aviation Administration (FAA) Service Difficulty Report (SDR) query revealed there were 12 SDR reports on the NLG forks, which included the three from the incident operator. Another operator had a fleet of 44 airplanes. This fleet’s airplanes accumulated 13 cracked NLG forks in 17 months. According to a fleet representative, their normal procedure for reporting failed parts was to submit the information directly to the manufacturer, instead of submitting a SDR. The airplane’s manufacturer recommended the installation of screws in the bolt holes used to secure the fairing to the NLG fork, which reportedly reduced a stress concentration point. The airplane manufacturer published a Service Information Letter (SIL), which depicted a replacement NLG fork assembly, and described the installation process. The SIL also referred owners to the maintenance manual for new inspection requirements that require the NLG to be inspected every 100 hours as opposed to the previous 6,000-hour inspection cycle. The National Transportation Safety Board issued recommendations to the FAA to encourage "all persons or organizations that operate under 14 CFR Parts 43 and 91 to submit Malfunction or Defect Reports ... and to ... encourage foreign regulatory agencies to provide service difficulty data from resident operators and manufacturers to the FAA for incorporation into the FAA service difficulty data base." ## Factual narrative On August 26, 2010, at time unknown, a Diamond Aircraft Industries Inc. DA 20-C1 airplane, N409AM, exhibited minor damage when a student pilot found a crack on its nose landing gear (NLG) fork during a preflight inspection at the Central Illinois Regional Airport at Bloomington-Normal, near Bloomington, Illinois. Visual meteorological conditions prevailed all day in the area. The operator reported no injuries. The instructional flight was to be operated under 14 Code of Federal Regulations Part 91. This cracked NLG fork, found by the student pilot during the preflight of the incident airplane, was the third cracked fork that the operator reported since March 30, 2009. The two previous cracked NLG fork occurrences were reported on April 7, 2009 and on March 30, 2009. This recent NLG fork accumulated 573.6 hours of total time before the crack was observed and the two previous forks accumulated 1,306.0 hours and 1,926.7 hours respectively. The incident airplane’s last inspection was a 100-hour inspection and it was completed on July 23, 2010. The cracks were in similar locations for all three occurrences. The NLG forks’ arms exhibited cracking near the bolt hole that is used to secure the fairing to the NLG fork. The NLG forks' part number (p/n) were: 20-3220-08-00. The Federal Aviation Administration Service Difficulty Report (SDR) query page was queried to determine how many Diamond Aircraft Industries Inc. cracked NLG forks were reported. There were 12 SDR reports on the NLG forks, which included the three from the incident operator. Another operator of DA 20-C1 airplanes was contacted in reference to NLG fork cracking. This operator had a fleet of 44 DA 20-C1 airplanes which were also used for flight instruction. A representative for this operator reported that his fleet’s airplanes averaged about 60 hours of flight time per month and that the fleet accumulated 13 cracked NLG forks between February 24, 2009 and July 14, 2010. He said that the NLG forks are replaced and a condition report is submitted directly to the manufacturer, which is their normal procedure for failed parts. Their total time on the forks before the cracks were observed ranged from 595.9 hours to 2,253.9 hours with an average of 1,371.09 hours. The representative further stated that the airplane’s manufacturer recommended the installation of screws in the bolt holes that are used to secure the fairing to the NLG fork. The installation was indicated to reduce a stress concentration point. Diamond Aircraft Industries Inc. had been working on a design change at the time of the incident with N409AM and subsequently published a Service Information Letter (SIL) 20C1-005. The SIL advised owners, worldwide, that the old NLG fork assembly P/N 20-3220-08-00 had been replaced with the new fork assembly, P/N 20-3220-08-00_1. The SIL further advised customers to install machine screws, pan head, P/N MS35207-282, with Loctite 242 when the wheel fairings are not used to avoid any potentialcracking that also may occur at that location. Lastly, the SIL refers owners to the Aircraft Maintenance Manual (AMM), Revision 17, dated November 1, 2010, for new inspection requirements for the NLG. The airplane inspection schedule in the AMM indicated that the NLG is now to be inspected every 100 hours as opposed to the previous revision’s 6,000-hour inspection cycle. The National Transportation Safety Board, in a letter dated June 3, 1993, to the FAA Administrator, issued recommendations in reference to SDRs. The letter, in part, stated: The Federal Aviation Administration's Service Difficulty Reporting (SDR) program is often used during aviation accident/incident investigations to research the history of aircraft failures, malfunctions, and defects. However, attempts to effectively use the SDR data base in recent Safety Board investigations have revealed that the current program is incomplete and of limited value in identifying accurate service defect histories because many reportable service difficulties are not reported to the FAA. ... The Safety Board is also concerned that the current efforts to improve the SDR system do not address the problems with general aviation Malfunction or Defect (M or D) Reports. Current Federal Aviation Regulations (FARs) require that holders of certificates under 14 Code of Federal Regulations (CFR) Parts 21, 121, 125, 127, 135, and 145 submit reports of service difficulties to the FAA for entry into the SDR system. Service difficulty reporting is currently not required under Parts 43 and 91. This factor may be contributing to low reporting, which significantly reduces the value and effectiveness of the program. Encouraging those who operate under the provisions of 14 CFR Parts 43 and 91 to submit M or D Reports, and providing appropriate guidance to them, would improve the quality and content of the general aviation SDR data base. The letter included the following recommendations to the FAA: Review the reporting items and establish standardized reporting formats for Malfunction or Defect Reports and Service Difficulty Reports that include the capability for electronic submission. Encourage all operations under 14 CFR Parts 21, 43, 91, 121, 125, 127, 135, and 145 to use electronic reporting methods for submission of service difficulty information. (Class II, Priority Action) (A-93-61) Encourage all persons or organizations that operate under 14 CFR Parts 43 and 91 to submit Malfunction or Defect Reports and provide appropriate guidance to improve the quality and content of the general aviation service difficulty data base. (Class II, Priority Action) (A-93-62) Ensure that prompt analysis of service difficulty reports and dissemination of alerting information is being accomplished in accordance with Federal Aviation Administration policies and procedures. (Class II, Priority Action) (A-93-63) Encourage foreign regulatory agencies to provide service difficulty data from resident operators and manufacturers tothe Federal Aviation Administration (FAA) for incorporation into the FAA service difficulty data base. (Class II, Priority Action) (A-93-64) The status of these recommendations, at the time of publishing of this incident report, are closed-unacceptable action for A-93-61 and closed-acceptable action for A-93-62, A-93-63, and A-93-64. ## Aircraft - Registration: [N409AM](https://openairdocs.org/deregistered/N409AM-2016-07-06), registration cancelled 2016-07-06, S/N C0343, built 2005 (OpenAirDocs) - Reported make and model: DIAMOND AIRCRAFT IND INC DA 20-C1 - Registry model: [Diamond Aircraft Ind DA20-C1](https://openairdocs.org/model/diamond-aircraft-ind-da20-c1) (registry code 2990001) (OpenAirDocs) - Registry engine: [Continental IO-240-B](https://openairdocs.org/engine/continental-io-240-b) (registry code 17177, reciprocating) (OpenAirDocs) - Category: Airplane - Serial number: C0343 - Airframe hours: 1801 - Engines: CONT MOTOR IO-240-B 125 horsepower reciprocating - Damage: Minor damage - Flight: Instructional, Part 91 - Operator: Image Air Of Southwest Florida Lc - Registered owner: Image Air Of Southwest Florida Lc - Airworthiness certificate: Standard, Normal - Last inspection: 100 hour, July 23, 2010 - Departed: BMI, Bloomington, IL - Destination: BMI, Bloomington, IL - Flight plan: Unknown - Airport: BMI, Central Illinois Regional ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; injuries: none; student; medical: class 3, unknown ## Weather - Conditions: Visual (VMC), Not reported - Visibility: 10 statute miles - Observed at: BMI ## Docket (5 files) The files NTSB released with the investigation on January 10, 2011, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=77382. 2.6 MB in all. - Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1 (item 1, .PDF, 2.3 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40339204&FileExtension=.PDF&FileName=Pilot%2FOperator%20Aircraft%20Accident%20Report,%20NTSB%20Form%206120.1-Master.PDF - Other Pertinent Forms and Reports - Service Difficulty Report (SDR) Query (item 2, .PDF, 25 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40339293&FileExtension=.PDF&FileName=Other%20Pertinent%20Forms%20and%20Reports%20-%20Service%20Difficulty%20Report%20(SDR)%20Query-Master.PDF - Photo - Incident Airplane (item 3, .PDF, 104 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40341456&FileExtension=.PDF&FileName=Photo%20-%20Incident%20Airplane-Master.PDF - Photo - Incident Nose Landing Gear Fork (item 4, .PDF, 175 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40341455&FileExtension=.PDF&FileName=Photo%20-%20Incident%20Nose%20Landing%20Gear%20Fork-Master.PDF - Correspondence - E-mail excerpt (item 5, .PDF, 51 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40339838&FileExtension=.PDF&FileName=Correspondence%20-%20E-mail%20excerpt-Master.PDF From the NTSB's public API. Aircraft are matched to registry aircraft by N-number and event date, checked against the reported serial number, make and model; the registry's history has gaps, so older matches can be wrong. Compare the reported make and model. --- OpenAirDocs.org is an independent research project of [Contrail Labs](https://contraillabs.com/). It is not affiliated with the FAA or the NTSB. Source documents are U.S. government works in the public domain.