# NTSB CHI08LA071: Airbus Industrie A319-114, N349NB, Detroit, MI, January 9, 2008 - Type: NTSB accident investigation - Classification: Accident · No injuries · Limited investigation · Final report - Date: January 9, 2008, 07:49 local (12:49 UTC) - Place: Detroit, MI - Coordinates: 42.212501, -83.353332 - Nearby events: https://openairdocs.org/map.md?lat=42.2125&lon=-83.3533&mi=10 - Phase of flight: [Approach](https://openairdocs.org/ntsb-phases/500) (OpenAirDocs' grouping) - Defining event: [Approach: Sys/Comp malf/fail (non-power)](https://openairdocs.org/ntsb-events/330) - Highest injury: No injuries - Injuries: 73 uninjured - Status: Completed, report May 28, 2008 - Report: Approved by Office Director - Parties: Federal Aviation Administration - NTSB case key (mKey): 67425 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=CHI08LA071 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/67425/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=67425 - Page: https://openairdocs.org/ntsb/CHI08LA071 ## Probable cause The separation of the engine cowling which resulted from maintenance personnel failing to follow maintenance procedures in that they did not latch the engine cowling following the maintenance inspection. A factor associated with the accident was their attention was divereted from the task when another mechanic asked for assistance. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Attention/monitoring: attention](https://openairdocs.org/ntsb-findings/02021510): Personnel issues › Psychological · Maintenance personnel (probable cause); cases with it: [Airbus A319-114, 1 case](https://openairdocs.org/ntsb-findings/02021510/cases.md?model=3940002), [All aircraft, 226 cases](https://openairdocs.org/ntsb-findings/02021510/cases.md) - [Power plant: engine cowling system](https://openairdocs.org/ntsb-findings/01057110): Aircraft › Aircraft power plant · Failure (probable cause); cases with it: [Airbus A319-114, 1 case](https://openairdocs.org/ntsb-findings/01057110/cases.md?model=3940002), [All aircraft, 11 cases](https://openairdocs.org/ntsb-findings/01057110/cases.md) - [Action: forgotten action/omission](https://openairdocs.org/ntsb-findings/02041035): Personnel issues › Action/decision · Maintenance personnel (probable cause); cases with it: [Airbus A319-114, 1 case](https://openairdocs.org/ntsb-findings/02041035/cases.md?model=3940002), [All aircraft, 440 cases](https://openairdocs.org/ntsb-findings/02041035/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Approach: Sys/Comp malf/fail (non-power)](https://openairdocs.org/ntsb-events/330) (defining event); cases with it: [Airbus A319-114, 1 case](https://openairdocs.org/ntsb-events/330/sequence.md?model=3940002), [All aircraft, 994 cases](https://openairdocs.org/ntsb-events/330/sequence.md) ## Analysis The accident flight was the first one for the airplane after having maintenance performed on the number two (right) engine during the previous evening. The first officer reported the engine cowls were flush and he did not see any "hanging" cowl latches when he looked underneath the engine cowls during the preflight. The captain reported the preflight, taxi, and takeoff were normal. During climb out the lead flight attendant informed the pilots that a passenger reported that the number two engine cowling was flapping after takeoff. The captain then began to monitor the N1 vibration indications on the number two engine. He reported that the vibration was approximately double the indication from the number one engine, but the indicator was not flashing, nor had it turned amber. The captain reported that during cruise flight the number two engine vibration decreased and about 20 minutes after they leveled off, the airplane shuddered. He reported the remainder of the flight was normal until they were taxiing after landing and the lead flight attendant called the cockpit stating that "part of the right engine had come off." Half of the engine cowl departed the airplane when it was on a one mile final. The other half departed the airplane as it touched down. Another airplane subsequently contacted this part of the cowling when it landed after the accident airplane. Contract maintenance personnel reported they changed the N1 sensor on the number two engine. They reported they shut the fan cowling, but did not latch it as they still needed to perform an engine run and check for leaks. They performed the engine run and were in the cockpit when another mechanic asked for help on another airplane. The mechanics left the accident airplane to assist the other mechanic. Neither mechanic returned to the accident airplane to either latch or verify that the fan cowling had been latched. The aircraft maintenance manual (AMM) instructions for replacing the N1 sensor states, "Close the fan cowl doors (Ref. AMM TASK 71-13-00-410-040)." This task was not completed prior to the airplane being returned to service. The separated cowling contacted the right side of the horizontal stabilizer which resulted in substantial damage to the stabilizer. In addition, the fan cowl doors, number two engine pylon, the number two engine reverser, and the right wing number one slat were damaged. ## Factual narrative On January 9, 2008, at 0749 eastern standard time, an Airbus Industrie A319-114, N349NB, operated by Northwest Airlines as flight 853, experienced an engine fan cowling separation while on approach to land on runway 27R at the Detroit Metro Airport (DTW), Detroit, Michigan. The pilot, co-pilot, 3 flight attendants, and 68 passengers on board were not injured. The airplane received substantial damage. The domestic passenger flight was being operated under 14 Code of Federal Regulations Part 121. The flight was operating in visual meteorological conditions and an instrument flight plan was filed. The flight originated from LaGuardia Airport (LGA), New York, New York, at 0618. The accident flight was the first one for the airplane after having maintenance performed on the number two (right) engine during the previous evening. The first officer reported he used a flashlight when conducting his preflight inspection of the airplane as it was still dark outside. He reported the engine cowlings were flush, and he did not see any "hanging" cowl latches when he looked underneath the engines. The captain reported that the logbooks indicated the number two engine vibration monitor had been replaced during the previous night. He reported the preflight, taxi, and takeoff were normal. The captain reported that during climb out the cockpit received a call from the lead flight attendant who informed them that a passenger reported that the number two engine cowling was flapping after takeoff. A pilot-passenger who was sitting behind this passenger reportedly did not see the cowling move, nor did the flight attendants when they looked out the window. The captain reported he then began to monitor the N1 vibration indications on the number two engine. He reported that the number two engine vibration was approximately double the indication from the number one engine, but the indicator was not flashing nor had it turned amber. During cruise flight the number two engine vibration decreased to equal that of the number one engine. The captain reported that about 20 minutes after they leveled off, the airplane shuddered as if flying through wake turbulence. The captain reported he then reviewed the logbooks and noticed previous write-ups regarding engine vibration, so he sent an AIRINC Communications Addressing and reporting System (ACARS) maintenance message regarding the current vibration. He reported the remainder of the flight was normal until they were taxiing after landing and the lead flight attendant called the cockpit stating that "part of the right engine had come off." The first officer called ground control to warn them that there might be debris on the runway. The crew then shut down the number two engine and taxied to the gate. The pilot of another airplane later reported seeing part of the engine cowling come off when flight 853 was on a 1-mile final. The other half of the engine cowling was found on the runway and was contacted by an airplane that landed after the accident airplane. Contract maintenance personnel reported they changed the N1 sensor on the number two engine during the evening prior to the accident. They reported they then shut the fan cowling, but did not latch it as they still needed to perform an engine run and check for leaks. After the engine run was performed, one of the mechanics thought that the other had latched the fan cowling when in fact he had not. While they were doing another task in the cockpit, another mechanic asked for help at another gate. The mechanics left the accident airplane to assist the other mechanic. Neither mechanic returned to the accident airplane to either latch or verify that the fan cowling had been latched. The maintenance log stated the N1 speed sensor was removed and replaced in accordance with aircraft maintenance manual (AMM) 77-11-10. This section of the AMM states, "Close the fan cowl doors (Ref. AMM TASK 71-13-00-410-040)." According to the maintenance personnel, this task was not completed prior to the airplane being returned to service. The separated cowling contacted the right side of the horizontal stabilizer which resulted in substantial damage to the stabilizer. In addition, the fan cowl doors, number two engine pylon, the number two engine reverser, and the right wing number one slat were damaged. ## Aircraft - Registration: [N349NB](https://openairdocs.org/aircraft/N349NB), registered now, S/N 1815, built 2002 (OpenAirDocs) - Reported make and model: Airbus Industrie A319-114 - Registry model: [Airbus A319-114](https://openairdocs.org/model/airbus-a319-114) (registry code 3940002) (OpenAirDocs) - Registry engine: [CFM International CFM56 series](https://openairdocs.org/engine/cfm-international-cfm56-series) (registry code 13802, turbo-fan) (OpenAirDocs) - Category: Airplane - Serial number: 1815 - Airframe hours: 15029 - Engines: CFM International CFM56-5-A5 23500 lbs thrust turbo fan - Damage: Substantial damage - Flight: Part 121 - Registered owner: Northwest Airlines Inc - Airworthiness certificate: Standard, Transport - Last inspection: Continuous airworthiness, July 1, 2007, 317 hours before - Departed: LGA, NEW YORK, NY - Destination: DTW, DETROIT, MI - Flight plan: IFR - Airport: DTW, Detroit Metro, runway 27R, 8,700 × 200 ft ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 52; injuries: none; airline transport, flight engineer; airplane ratings: multi-engine land; instrument ratings: airplane; medical: class 1, with waivers/limitations; last flight review July 1, 2006; seat: left; flight hours: 13,615 total, 8,079 in this make and model, 6,797 as pilot in command, 281 in the last 90 days, 88 in the last 30 days, 4 in the last 24 hours - Co-pilot; age 46; injuries: none; airline transport, flight engineer, commercial; airplane ratings: single-engine land, multi-engine land; instrument ratings: airplane; medical: class 1, without waivers/limitations; last flight review April 1, 2007; seat: rear; flight hours: 7,161 total, 4,103 in this make and model, 232 in the last 90 days, 66 in the last 30 days, 4 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: 280° at 15 knots - Visibility: 10 statute miles - Lowest ceiling: 3,800 ft broken - Temperature: 39 °F, dew point 30 °F - Altimeter: 29.89 inHg - Observed at: DTW, 1 nm away ## FAA reports on this event (1) The FAA's own accident and incident reports, matched to the aircraft by N-number and date (OpenAirDocs). - [Accident 20080109844059A](https://openairdocs.org/incident/20080109844059A), Jan 9, 2008: Airbus A319114, Detroit, MI, Substantial damage. (-23) On January 09, 2008 approx 0800 local nwa Airbus 319 N349NB had both nr 2 engine fan cowlings depart the aircrat prior to touchdown in dtw. One cowling… ## Docket (15 files) The files NTSB released with the investigation on May 12, 2008, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=67425. 3.8 MB in all. - Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1 (item 1, .PDF, 814 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40293802&FileExtension=.PDF&FileName=Pilot%2FOperator%20Aircraft%20Accident%20Report,%20NTSB%20Form%206120.1-Master.PDF - Crew Statements (item 2, .PDF, 395 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40429472&FileExtension=.PDF&FileName=Crew%20Statements-Redacted.PDF - Mechanic Statements (item 3, .PDF, 212 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40293804&FileExtension=.PDF&FileName=Mechanic%20Statements-Master.PDF - Maintenance Procedures (item 4, .PDF, 617 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40293805&FileExtension=.PDF&FileName=Maintenance%20Procedures-Master.PDF - Maintenance Log (item 5, .PDF, 67 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40293806&FileExtension=.PDF&FileName=Maintenance%20Log-Master.PDF - Photo 1. Outboard Section of Number 2 Engine (FAA Photo) (item 6, .PDF, 79 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40293807&FileExtension=.PDF&FileName=Photo%201.%20%20Outboard%20Section%20of%20Number%202%20Engine%20(FAA%20Photo)-Master.PDF - Photo 2. Inboard Section of Number 2 Engine (FAA Photo) (item 7, .PDF, 67 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40293808&FileExtension=.PDF&FileName=Photo%202.%20%20Inboard%20Section%20of%20Number%202%20Engine%20(FAA%20Photo)-Master.PDF - Photo 3. Damage to Number 2 Engine (FAA Photo) (item 8, .PDF, 50 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40293809&FileExtension=.PDF&FileName=Photo%203.%20%20Damage%20to%20Number%202%20Engine%20(FAA%20Photo)-Master.PDF - Photo 4. Damage to Engine Pylon (FAA Photo) (item 9, .PDF, 59 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40293810&FileExtension=.PDF&FileName=Photo%204.%20%20Damage%20to%20Engine%20Pylon%20(FAA%20Photo)-Master.PDF - Photo 5. Damage to Engine Pylon Structure (FAA Photo) (item 10, .PDF, 61 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40293811&FileExtension=.PDF&FileName=Photo%205.%20%20Damage%20to%20Engine%20Pylon%20Structure%20(FAA%20Photo)-Master.PDF - Photo 6. Number 2 Engine Fan Cowling (FAA Photo) (item 11, .PDF, 59 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40293812&FileExtension=.PDF&FileName=Photo%206.%20%20Number%202%20Engine%20Fan%20Cowling%20(FAA%20Photo)-Master.PDF - Photo 7. Right Horizontal Stabilizer (FAA Photo) (item 12, .PDF, 50 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40293813&FileExtension=.PDF&FileName=Photo%207.%20%20Right%20Horizontal%20Stabilizer%20(FAA%20Photo)-Master.PDF - Photo 8. Right Horizontal Stabilizer (FAA Photo) (item 13, .PDF, 363 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40293814&FileExtension=.PDF&FileName=Photo%208.%20%20Right%20Horizontal%20Stabilizer%20(FAA%20Photo)-Master.PDF - Photo 9. Number 2 Engine Pylon (FAA Photo) (item 14, .PDF, 422 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40293815&FileExtension=.PDF&FileName=Photo%209.%20%20Number%202%20Engine%20Pylon%20(FAA%20Photo)-Master.PDF - Photo 10. Number 2 Engine Pylon (FAA Photo) (item 15, .PDF, 499 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40293816&FileExtension=.PDF&FileName=Photo%2010.%20%20Number%202%20Engine%20Pylon%20(FAA%20Photo)-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.