# NTSB DEN05IA027: McDonnell Douglas DC-9-82, N234AA, Denver, CO, November 21, 2004 - Type: NTSB incident investigation - Classification: Incident · No injuries · Incident investigation · Final report - Date: November 21, 2004, 10:38 local (17:38 UTC) - Place: Denver, CO - Coordinates: 39.827499, -104.660552 - Nearby events: https://openairdocs.org/map.md?lat=39.8275&lon=-104.6606&mi=10 - Phase of flight: [Approach](https://openairdocs.org/ntsb-phases/500) (OpenAirDocs' grouping) - Highest injury: No injuries - Injuries: 106 uninjured - Status: Completed, report July 7, 2005 - Report: Approved by Office Director - Parties: Boeing Commercial Airplanes, Federal Aviation Administration, Allied Pilots Association, American Airlines - NTSB case key (mKey): 60590 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=DEN05IA027 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/60590/pdf - Page: https://openairdocs.org/ntsb/DEN05IA027 ## Probable cause the first officer's failure to maintain proper glide slope during the landing approach, and the captain's failure to adequately monitor the approach and landing, and his failure to challenge and/or intervene when the first officer continued to descend below the glide slope. Factors contributing to the incident were the first officer's lack of recent experience in flying a complete ILS approach in actual instrument conditions, the low ceilings and fog. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - In flight collision with object, approach - proper glidepath - not maintained, copilot/second pilot (cause) - lack of recent experience in type operation, copilot/second pilot (contributing factor) - object - approach light/navaid - monitoring - inadequate, pilot in command - object - runway light - remedial action - inadequate, pilot in command (cause) - weather condition - low ceiling (contributing factor) - weather condition - fog (contributing factor) ## Analysis The first officer was hand-flying the airplane. During the descent for the approach, the crew received a special observation that the weather was ceilings 300 and 1,000 feet broken and 1/2 mile visibility and fog. The crew briefed the ILS approach for runway 35L. When approach control (TRACON) cleared the airplane for the ILS approach, the airplane was at 9,000 feet. The captain reported that as they continued, the glide slope indicator "came up and actually went below us," and that the airplane had not yet intercepted the localizer. The captain asked TRACON for a lower altitude. TRACON "apologized" and cleared the airplane to 7,000 feet, and then asked the crew if they would still be okay for the approach. The crew said they would be okay. The captain said the airplane was configured and was approaching the glide slope from above, as it was intercepting the localizer. He said the first officer was on the localizer and glide slope. At 100 feet, the captain called approach lights in sight, and the first officer acknowledged. When the captain called reaching the decision altitude, the first officer called landing. The captain said he started to see the threshold lights and then heard the "glide slope" GPWS (Ground Proximity Warning System) warning. The captain called "pull up" to the first officer. The captain said as they touched down he thought he could see some approach light bars below the nose, but did not feel or hear anything unusual. The landing roll out was normal. After parking, the crew discovered damage to the left main brake line and loss of hydraulic fluid from the right system. The airplane showed additional damage to the left main tires, bottom left aft portion of the fuselage, and to the left engine and left engine cowling. An examination of the runway showed one approach light, 19 feet from the beginning of the paved overrun, broken forward at its base. Approximately 49 feet from the start of the paved overrun surface, the beginning of two pairs of parallel-running tire marks were observed. The left pair of tire marks ran through three sets of center approach lights in the overrun, two runway threshold lights, a distance of 354 feet, and continued down runway 35L for approximately 700 feet. Light stanchions, broken lens pieces, and bulb debris was observed extending down the runway along the tire marks. An examination of the airplane's avionics equipment and the airport's ILS approach showed no anomalies. The flight data recorder (FDR) showed that the airplane captured the ILS glide slope 38 seconds prior to touchdown at a radio altitude of 734 feet. The FDR pitch, recorded 4 seconds later, indicated the airplane was tracking the glide slope and at a radio altitude of 617 feet. At 5 seconds prior to touchdown, the glide slope showed a 2 dots fly up deviation. The airplane was at a radio altitude of 114 feet. The glide slope warning was on. The glide slope continued to increase reaching 4.3 dots fly up at touchdown. The airplane's airspeed at touchdown was 133.5 knots. Vertical acceleration was 1.7 g's followed by 0.7 g's approximately 1/2 second later. Lateral acceleration was -0.15 g's. The right outboard spoiler began to deploy at touchdown plus 2.5 seconds. The hydraulic pressure low lights (left and right) remained in an "off" state throughout the incident sequence. Flight crews are administered a simulator check every 9 months, either by the company or the FAA. Crews do not fly practice approaches in the airplane. The first officer's last simulator checkride was 14 months prior to the incident. The first officer stated he could not recall when the last time was that he flew an instrument approach in the airplane in actual weather conditions. ## Factual narrative HISTORY OF FLIGHT On November 21, 2004, at 1038 mountain standard time, a McDonnell Douglas DC-9-82, N234AA, operating as American Airlines Flight 1115, sustained minor damage when during landing at the Denver International Airport (DEN), Denver, Colorado, the airplane struck several approach and runway threshold lights. Instrument meteorological conditions prevailed at the time of the incident. The scheduled domestic passenger flight was being conducted on an instrument flight rules flight plan under the provisions of Title 14 CFR Part 121. The captain, first officer, 3 flight attendants, and 101 passengers on board reported no injuries. The flight originated at the Dallas-Fort Worth International Airport, Ft. Worth, Texas, at 1004 central standard time, and was en route to DEN. The captain reported that the first officer was flying the airplane. The crew received two previous ATIS (Automated Terminal Information System) reports that DEN weather was VFR (Visual Flight Rules). At 1017, the company's dispatch informed the crew of a special observation that DEN weather was ceilings 300 feet and 1,000 feet broken, and 1/2 mile visibility and fog. The crew briefed the ILS (Instrument Landing System) approach for runway 35L. The captain reported that when DEN Approach Control (TRACON) cleared the airplane for the ILS approach, the airplane was at 9,000 feet. The fog bank over the airport looked at if it went from the surface to 6,500 feet. The captain said that as they continued, the glide slope indicator "came up and actually went below us," and that the airplane was not yet on the localizer. The captain asked DEN TRACON for lower [altitude]. TRACON "apologized," cleared the airplane to 7,000 feet, and asked the crew if they would still be okay for the approach. The crew felt that they would be okay to continue. The airplane was configured and was approaching the glide slope from above, as it was intercepting the localizer. The crew finished the checklist at 1,000 feet. The first officer was on the localizer and glide slope. The crew was cleared to land. At 100 feet, the captain called approach lights in sight, and the first officer acknowledged. When the captain called reaching the decision altitude, the first officer called landing. The captain said he started to see the threshold lights and then heard the "glide slope" GPWS (Ground Proximity Warning System) warning. The captain said he called "pull up." He said as they touched down he thought he could see some approach light bars below the nose, but did not feel or hear anything unusual. The landing roll out was normal. After parking, the crew discovered damage to the left main brake line and loss of hydraulic fluid from the right system. The first officer said they began the day in Dallas. It was the second day of a 2-day trip. He said they had good weather in Dallas and good weather en route. The first officer said that he was flying the airplane. He said that the initial weather they received for Denver was good - VFR. He said at one point, they received Denver ATIS (Automated Terminal Information System) over ACARS - it was VFR and landing to the south. Later, they received an ATIS report stating that Denver was still VFR, but landing to the north. The first officer said that somewhere nearing Denver, they received a message from their company dispatch that the airport had gone to 1/4-mile visibility. The first officer said they switched to Denver ATIS again. The reported weather at Denver was 100 broken, 1/4-mile visibility and fog, and landing to the north. They decided to plan for a category one ILS to one of the runway 35s. The first officer said he thought it would be 35R, so he briefed that approach. He said they started descending about 80 to 90 miles from the airport. The weather was good - clear weather at, above, and below. Approximately 50 miles from Denver he turned off the autopilot and throttles, and hand flew the airplane. He said they were handed over to approach control. Approach control gave them vectors to the ILS for runway 35L. The captain and the first officer went over the changes to the approach. The first officer said that during the vectors, approach control gave them speed reductions. He said they began configuring with slats. He said that the final airspeed he recalled they gave was 170 knots. He said then they went to flaps 15 degrees. The approach controller assigned them 9,000 feet, and gave them a heading to the localizer for 35L. The first officer said that the intercept heading was very shallow, about 340 degrees. He said he figured they were close to the localizer. At 9,000 feet and 170 knots, with the localizer indicator bar still on the side, the glide slope indicator bar began to come down. As it was coming down and through center, the first officer asked the captain to tune in Denver VOR to see where they were laterally. He did and said that they were 5 degrees off of centerline. The first officer said, "We need lower." The captain called approach and said they needed lower. Approach Control gave them 7,000 feet for the intercept. The first officer said that at that point, the controller apologized for the vector and asked if they would be okay, and did they want to be brought back around to set up for the approach again? The first officer said that he and the captain thought they would be okay. The localizer bar came off the side of the case. The first officer asked the captain to lower the landing gear and set the flaps to 28 degrees, then 40 degrees. The first officer said, "We started descending to catch up to the glide slope. I believe we were around DYMON (a published fix on the approach) when the glide slope came back. We continued down centered on the glide slope. The speed was fast, but coming back. It was still VMC. I could see the ground right under us, but could not see the runway looking straight ahead. I believe I could see runway 35R. Other than that, I had no concerns about flying the approach." The first officer said that the captain switched to the localizer on his panel and finished the before landing checklist. At 1,000 feet, the captain announced "checklist complete." The first officer said they were stable on glide slope and localizer, but 20 knots fast. The speed was coming back. At 500 feet above the ground, the first officer said they were at "ref (approach speed) plus 10 or 15 knots." About 100 feet above decision height, the captain announced "approach lights in sight." The first officer said he looked up and saw the approach lights and threshold lights. He said that at one point he saw side rail bars on the approach system. He said he had good visual cues to continue in. The first officer said that at decision height he said "landing." He said that his attention was really focused outside. The approach looked good. He said that at some point, they got a glide slope warning on GPWS (Ground Proximity Warning System). He said, "We got two call outs on that I believe." The captain said, "You're low, pull up." The first officer said he thought he was pulling up, but it was not enough. The first officer said that after touchdown, both he and the captain saw they were short. He said they didn't experience any noises, jolts, or adverse yawing. Air traffic control data showed that at 1031:05, the TRACON instructed American 1115 to fly a 320 degree heading to intercept the localizer to runway 35L. At 1031:42, TRACON instructed American 1115 to maintain 9,000 until established on the localizer, and cleared the airplane for the ILS approach. At 1035:37, TRACON instructed American 1115 to contact the tower. American 1115 responded, " ... we haven't intercepted the, ah, localizer yet. Can we have lower?" The TRACON controller instructed, " ... maintain 7,000 till established", and then said, "I'm sorry." Then the controller ## Aircraft - Registration: [N234AA](https://openairdocs.org/deregistered/N234AA-2010-06-09), registration cancelled 2010-06-09, S/N 49181, built 1983 (OpenAirDocs) - Reported make and model: McDonnell Douglas DC-9-82 - Registry model: [Mcdonnell Douglas DC-9-82(MD-82)](https://openairdocs.org/model/mcdonnell-douglas-dc-9-82-md-82) (registry code 3022082) (OpenAirDocs) - Registry engine: [Pratt & Whitney JT8D series](https://openairdocs.org/engine/pratt-whitney-jt8d-series) (registry code 52053, turbo-jet) (OpenAirDocs) - Category: Airplane - Serial number: 49181 - Airframe hours: 64213.41 - Engines: Pratt & Whitney JT8-217C 20000 lbs thrust turbo fan; Pratt & Whitney JT8-217C 20000 lbs thrust turbo fan - Damage: Minor damage - Flight: Part 121 - Operator: American Airlines, Incorporated, doing business as American Airlines - Registered owner: CIT Leasing Corp. - Airworthiness certificate: Standard, Transport - Last inspection: Continuous airworthiness, November 20, 2004, 2.9 hours before - Departed: DFW, Fort Worth, TX - Destination: DEN, Denver, CO - Flight plan: IFR - Airport: DEN, Denver International Airport, runway 35L, 12,000 × 150 ft, concrete ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 57; injuries: none; flight engineer, airline transport, commercial; airplane ratings: multi-engine land, single-engine land; instrument ratings: airplane; medical: class 1, valid medical--w/ waivers/lim; last flight review July 23, 2004; seat: left; flight hours: 12,705 total, 8,483 in this make and model, 4,291 as pilot in command, 181 in the last 90 days, 78 in the last 30 days, 6 in the last 24 hours - Co-pilot; age 53; injuries: none; airline transport, flight instructor, flight engineer; airplane ratings: single-engine land, multi-engine land; instrument ratings: airplane; medical: class 2; last flight review September 19, 2003; seat: right; flight hours: 20,000 total, 1,000 in this make and model, 17,000 as pilot in command ## Weather - Conditions: Instrument (IMC), Day - Wind: 320° at 8 knots - Visibility: 0.25 statute miles - Lowest ceiling: 100 ft broken - Temperature: 27 °F, dew point 25 °F - Altimeter: 30.12 inHg - Observed at: DEN, 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). - [Incident 20041121031919I](https://openairdocs.org/incident/20041121031919I), Nov 21, 2004: Doug DC982, Denver, CO, Minor damage. (-23) On November 21, 2004, at 1038 mountain standard time, a mcdonnel Douglas DC-9-82, N234AA, operated as American airlines flight 1115, sustained minor… 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.