DCA96MA068

NTSB accident investigation · McDonnell Douglas MD-88 · Pensacola, FL · July 6, 1996

Accident · FatalClass 1 · MajorFinal report
Date
July 6, 1996, 14:24 local (19:24 UTC)
Place
Pensacola, FL
Injuries
2 fatal, 2 serious, 3 minor, 137 uninjured
Damage
Substantial damage
Phase of flight
Takeoff
Aircraft
N927DAMcDonnell Douglas MD-88
Weather
Visual (VMC) · Day
Status
Completed · report March 31, 1998
Report
Board-adopted at Board Meeting
Investigation class
Class 1
NTSB office
Major Investigations Division
Safety recommendations
Yes
FAA report
19960706016239A
Case key
11010

From the NTSB’s public API. By law, NTSB reports can’t be used as evidence in lawsuits over the accident.

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Probable cause

the fracture of the left engine's front compressor fan hub, which resulted from the failure of Delta Air Lines' fluorescent penetrant inspection process to detect a detectable fatigue crack initiating from an area of altered microstructure that was created during the drilling process by Volvo for Pratt & Whitney and that went undetected at the time of manufacture. Contributing to the accident was the lack of sufficient redundancy in the in-service inspection program. (NTSB Report AAR-98/01)

Sequence of events

NTSB’s coding before 2008: each occurrence and phase of flight, and the causes and factors under it. The codes are defined in NTSB’s coding manual.

Loss of engine power(total) - mech failure/malfTakeoff - roll/run
1 engine
Compressor assembly,rotor disc - fatigueCause
Maintenance,inspection - inadequateCompany maintenance personnelCause
Compressor assembly,rotor disc - fracturedCause
Compressor assembly,rotor disc - separation
Miscellaneous/otherTakeoff - roll/run
Misc,engine uncontained failure
Fuselage,cabin - foreign object damage

Analysis

During the initial part of its takeoff roll, the airplane experienced an engine failure. Uncontained engine debris from the front compressor front hub (fan hub) of the #1 (left) engine penetrated the left aft fuselage. Two passengers were killed and two others were seriously injured. The takeoff was rejected, and the airplane was stopped on the runway. The fan hub had fractured through a tierod hole and blade slot. Some form of drill breakage or drill breakdown, combined with localized loss of coolant and chip packing, had occurred during the drilling process, creating an altered microstructure and ladder cracking in the fan hub. Drilling damage extended much deeper into hole sidewall material than previously anticipated by P & W. Fatigue cracks initiated from the ladder cracking in the tierod hole and began propagating almost immediately after the hub was put into service in 1990. The crack was large enough to have been detectable during the last fluorescent penetrant inspection at Delta. Delta's nondetection of the crack was caused either by a failure of the cleaning and fluorescent penetrant inspection processing, a failure of the inspector to detect the crack, or some combination of these factors.

Factual narrative

On July 6, 1996, Delta Airlines flight 1288, an MD-88, N927DA, experienced an uncontained failure of the left engine during the beginning of the takeoff roll. The flightcrew stopped the airplane about 1400 feet down the takeoff runway. On board the airplane were 137 passengers, 2 flightcrew members, 3 cabincrew, and 2 non-revenue Delta employees occupying the cockpit and aft jumpseats. Engine parts entered the left side of the aft cabin resulting in 2 passengers sustaining fatal injuries and 2 sustained major injuries. Three other passengers received minor injuries during the evacuation. The captain stopped the evacuation from the emergency exits, and an airstair was brought to the airplane to evacuate the remaining passengers and the crew. The fan hub for the left engine was found fractured.

Aircraft

Registration
N927DA
Reported as
McDonnell Douglas MD-88
Category
Airplane
Serial number
49714
Airframe hours
22,031
Engine
P&W JT8D-219, 21,000 lbs thrust, turbo jet
Damage
Substantial damage
Fire
On-Ground
Flight
Part 121
Registered owner
Delta Air Lines Inc
Airworthiness certificate
Standard, Transport
Departed
PNS
Destination
ATL · Atlanta, GA
Flight plan
IFR
Airport
PNS · Pensacola Regional, runway 17, 7,002 × 150 ft, asphalt

Matched to the registry by N-number and the event date; the registry’s history has gaps, so older matches can be wrong. Compare the reported make and model.

Flight crew · 2

As NTSB recorded them. NTSB leaves out names.

Role
Pilot
Age
40
Certificate
Airline transport
Airplane ratings
Multi-engine land
Instrument ratings
Airplane
Medical
Class 1, Valid Medical--w/ waivers/lim
Seat
Left
Toxicology
Performed
Flight hours
12,000 total · 2,300 in this make and model · 142 in the last 90 days · 39 in the last 30 days
Role
Co-pilot
Age
37
Certificate
Airline transport
Airplane ratings
Single-engine land, Multi-engine land
Instrument ratings
Airplane
Medical
Class 1, Without waivers/limitations
Seat
Right
Toxicology
Performed

Weather

Conditions
Visual (VMC) · Day
Wind
210° at 12 knots
Visibility
7 statute miles
Temperature
90 °F, dew point 77 °F
Altimeter
29.00 inHg
Observed at
PNS

Docket · 183

The files NTSB released with the investigation on March 25, 1997, on NTSB’s docket system: statements, records, photos and specialists’ reports. 94.6 MB in all.

Ordering of Hearing: 1AItem 1 · .PDF · 48 KBNotice of Designation of Chairman of Board of Inquiry: 1BItem 2 · .PDF · 55 KBDesignation of Hearing Officer: 1CItem 3 · .PDF · 52 KBDesignation of Parties to the Hearing: 1DItem 4 · .PDF · 60 KBNotice of Hearing: 1EItem 5 · .PDF · 55 KBOperations 2 -Exhibit No. 2A - Group Chairman Factual Report - Operational Factors/Human PerformanceItem 6 · .PDF · 384 KBOperations 2 - Attachment 1 - Log of Aircraft N927DA MovementItem 7 · .PDF · 117 KBOperations 2 - Attachment 2 - Copy of Pilot's Trip SequenceItem 8 · .PDF · 73 KBOperations 2 - Attachment 3 - Copies of DL 1288 Flight Papers and Weight & BalanceItem 9 · .PDF · 665 KBOperations 2 - Attachment 4 - Aircraft Emergency Equipment and Seat LocationItem 10 · .PDF · 55 KBOperations 2 - Attachment 5 - Copy of ACARS LogItem 11 · .PDF · 84 KBOperations 2 - Attachment 6 - Copy of Engine Instruments and Operating ParametersItem 12 · .PDF · 281 KBOperations 2 - Attachment 7 - Copy of Normal Takeoff ProceduresItem 13 · .PDF · 73 KBOperations 2 - Attachment 8 - Copy of Pilot's Rejected Takeoff ProceduresItem 14 · .PDF · 119 KBOperations 2 - Attachment 9 - Copy of Pilot's Passenger Evacuation ProceduresItem 15 · .PDF · 147 KBOperations 2 - Attachment 10- Emergency Lights, Emergency Exits Location and OperationItem 16 · .PDF · 720 KBOperations 2 - Attachment 11- Throttle and Fuel Control Lever LocationItem 17 · .PDF · 95 KBOperations 2 - Attachment 12- Engine Fire Handle LocationItem 18 · .PDF · 102 KBOperations 2 - Attachment 13- Airport InformationItem 19 · .PDF · 438 KBOperations 2 - Attachment 14-Air Traffic Control Voice TranscriptsItem 20 · .PDF · 764 KBSurvival Factors 6 - Group Chairman Factual ReportItem 21 · .PDF · 235 KBSurvival Factors 6 - Attachment A - Crew and Passenger Seats, Restraint Systems, and Safety AppliancesItem 22 · .PDF · 404 KBSurvival Factors 6 - Attachment B - Airplane Cabin DiagramItem 23 · .PDF · 41 KBSurvival Factors 6 - Attachment C - Photographic SupplementItem 24 · .PDF · 476 KBSurvival Factors 6 - Attachment D - Flight Attendant InterviewsItem 25 · .PDF · 393 KBSurvival Factors 6 - Attachment E - Passenger and Other Witness InterviewsItem 26 · .PDF · 237 KBSurvival Factors 6 - Attachment F - Flight Attendant Training RecordsItem 27 · .PDF · 238 KBSurvival Factors 6 - Attachment G - Passenger Safety Briefing CardItem 28 · .PDF · 393 KBStructures 7 - Exhibit No. 7A - Group Chairman Factual Report - Structures/SystemsItem 29 · .PDF · 471 KBPhoto 1. N927DA on runway 17 after coming to a stop. The oil streak is visible left of the runway centerline.Item 30 · .PDF · 36 KBPhoto 2. Aerial view showing damage to left fuselage and left engine.Item 31 · .PDF · 36 KBPhoto 3. Left fuselage penetration damage.Item 32 · .PDF · 29 KBPhoto 4. Left fuselage and engine damage, including fire damage to nacelle.Item 33 · .PDF · 42 KBPhoto 5. Right fuselage exit damage.Item 34 · .PDF · 32 KBPhoto 6. Fragment damage to left wingtip.Item 35 · .PDF · 37 KBPhoto 7. Wire gundle located along right longeron 4; 146 of the 154 wires in the wire bundle had been severed.Item 36 · .PDF · 49 KBPhoto 8. Interior view of left fuselage penetration damage adjacent to row 37.Item 37 · .PDF · 52 KBPhoto 9. Interior view of left fuselage penetration damage adjacent to row 37.Item 38 · .PDF · 48 KBStructures 7 - Exhibit No. 7B - Wreckage Distribution, Hub Piece LocationsItem 39 · .PDF · 86 KBStructures 7 - Exhibit No. 7C - Wreckage Photographs (3)Item 40 · .PDF · 69 KBPowerplants 8 - Exhibit No. 8A - Group Chairman Factual ReportItem 41 · .PDF · 457 KBPowerplants 8 - Exhibit No. 8B - Figures and PhotographsItem 42 · .PDF · 466 KBPowerplants 8 - Exhibit No. 8B-1 - Volva Manufacturing Drawing 0-169282 Sheets 1 and 4 - Volvo Hub Front Drill Process HistoryItem 43 · .PDF · 232 KBPowerplants 8 - Exhibit No. 8C - Powerplants Group Chairman's Factual Report of Investigation NTSB Accident MIA82IA051 March 18, 1982Item 44 · .PDF · 685 KBPowerplants 8 - Exhibit No. 8D - Pratt & Whitney Research Report 704297-2440 April 5, 1982Item 45 · .PDF · 582 KBPowerplants 8 - Exhibit No. 8E - Technical Review of Fluorescent Penetrant Process Delta Airlines, Inc.. August 13 & 14, 1996Item 46 · .PDF · 1.1 MBPowerplants 8 - Exhibit No. 8F - ANE-180 Evaluation Report of Pratt & Whitney Quality System - September 30, 1996Item 47 · .PDF · 259 KBPowerplants 8 - Exhibit No. 8G - Attachment 1 - Phase 1 Report (Pratt & Whitney)Item 48 · .PDF · 1.6 MBPowerplants 8 - Exhibit No. 8H - Attachment 2 - Phase II Report (Volvo)Item 49 · .PDF · 886 KBPowerplants 8 - Exhibit No. 8I - Pratt & Whitney Chart Process Control/Quality Inspections of a Titanium Part (Undated)Item 50 · .PDF · 43 KBPowerplants 8 - Exhibit No. 8J - JT8D-200 Series Fan Hub Industry MeetingItem 51 · .PDF · 2.8 MBPowerplants 8 - Exhibit No. 8K - 14 CFR Parts 21 and 33 Selected PapersItem 52 · .PDF · 780 KBPowerplants 8 - Exhibit No. 8L - Volvo Aero Corporation Drill TypeItem 53 · .PDF · 5 KBPhoto 1. Drill TypeItem 54 · .PDF · 29 KBPowerplants 8 - Exhibit No. 8M - Volvo Aero Corporation Drilling with HSSItem 55 · .PDF · 6 KBPhoto 1. Drilling with HSSItem 56 · .PDF · 41 KBPowerplants 8 -Exhibit No. 8N - Volvo Aero Corporation Quality SystemItem 57 · .PDF · 4 KBPhoto 1. Volvo Aero Corporation Quality SystemItem 58 · .PDF · 35 KBPowerplants 8 - Exhibit No. 8O - Volvo Aero Corporation Quality System 1988Item 59 · .PDF · 4 KBPhoto 1. Volvo Aero Corporation Quality System 1988Item 60 · .PDF · 33 KB
All 183 files on NTSB’s docket

FAA reports on this event · 1

The FAA’s own accident and incident reports, matched to the aircraft by N-number and date.