McDonnell Douglas DC-8-71F accident at Pennsylvania, 7 Feb 2006

Accident narrative

On February 7, 2006, about 2359 eastern standard time, United Parcel Service Company (UPS) flight 1307, a McDonnell Douglas DC-8-71F, landed at Philadelphia International Airport in Pennsylvania after a cargo smoke indication in the cockpit. The captain, first officer, and flight engineer evacuated the airplane after landing and sustained minor injuries. The airplane and most of the cargo were destroyed by fire.

### The flight

The scheduled cargo flight was operating under instrument flight rules from Hartsfield-Jackson Atlanta International Airport to Philadelphia. Night visual conditions prevailed.

The captain, 59, had accumulated about 25,000 total flight hours, including 16,000 hours as pilot-in-command in DC-8 airplanes. The first officer, 40, had 7,500 total flight hours, with 2,100 hours as second-in-command in DC-8 airplanes. The flight engineer, 61, had 9,000 total flight hours, including 430 hours in DC-8 airplanes. The Safety Board concluded that no evidence indicated fatigue or any preexisting medical condition degraded the performance of the flight crewmembers.

The airplane, manufactured in 1967, had accumulated about 67,675 total flight hours. It was configured with 18 main cargo containers and four lower cargo compartments.

### The sequence of events

The airplane departed Atlanta about 2241. The first officer was the flying pilot, and the captain performed the duties of the pilot monitoring.

At 2334:39, as the airplane descended through 31,000 feet about 50 nautical miles southwest of Washington, D.C., the first officer asked the other crewmembers if they detected an odor that smelled "like wood burning." The flight engineer replied that he had smelled it for a couple of seconds. About one minute later, the first officer stated the odor was "pretty strong now." The flight engineer checked the area behind the cockpit, pulling back the smoke curtain and shining a flashlight along the left wall of the main cargo compartment. He stated that the odor was "more in the back" but that he did not see any smoke or fire.

The captain stated during postaccident interviews that he considered diverting but chose to continue to Philadelphia because there was no evidence of a problem, such as the illumination of cargo smoke warning lights, and because unusual odors could be common from nonthreatening factors. The Safety Board concluded that the flight crew’s continued descent to Philadelphia was not inappropriate given that there was no evidence of abnormalities other than the odor and that no cockpit alerts had activated.

Over the next four minutes, the crew tried to identify the source of the odor. As the airplane descended through about 18,000 feet, the flight engineer set the air conditioning packs to maximum flow and turned off the recirculation fan.

At 2344:59, the first officer contacted Philadelphia approach control, and the flight was instructed to descend to 6,000 feet. The first officer noted the odor smelled like cardboard burning. The flight engineer again checked the main cargo compartment with his flashlight, stating the odor was "definitely stronger in the back" but that there was no smoke or haze.

At 2354:42, as the airplane descended through about 3,600 feet, the flight engineer stated, "we got cargo smoke," referring to the illumination of the amber Cargo Smoke warning light. The captain called for the checklist, and the first officer stated he would be turning toward the airport. At 2355:01, approach control cleared the visual approach to runway 27R. The captain contacted the local controller, reported the cargo smoke indicator, and requested that emergency response equipment meet them upon landing.

At 2355:57, the flight engineer stated that the system was showing a lower aft cargo fire. The captain told the crew to don their oxygen masks and asked the flight engineer to accomplish the Lower and/or Main Cargo Compartment Smoke or Fire checklist.

At 2356:12, the local controller cleared the flight to land on runway 27L, which was the runway designated for emergency situations. The captain acknowledged the landing clearance but not the change in landing runway.

As the flight engineer continued the checklist, he opened the door of the access panel to the cargo air shutoff valve. He later stated that black smoke billowed out of the panel.

At 2357:47, the first officer called for the Landing checklist. Shortly after, the local controller noted the airplane appeared to be lined up for the right runway. The first officer asked if they were cleared for the right, and at 2358:16, the controller cleared them to land on runway 27R.

The airplane landed about 2359. Immediately after touchdown, the flight engineer reported smoke in the cockpit. After the airplane stopped, the first officer called for an emergency evacuation. The first officer later stated that the smoke was so heavy he could not see his hand in front of him. Both the captain and the first officer attempted to locate the notice to captain (NOTOC), which contained the shipping documentation describing the hazardous materials on board, but could not find it. All three crewmembers successfully evacuated using the emergency slide at the left forward (L1) door.

### Emergency response

Aircraft rescue and firefighting (ARFF) vehicles were originally headed to runway 27L; the change to runway 27R resulted in a 60- to 90-second delay. Seven ARFF vehicles responded, arriving as the flight crew evacuated.

ARFF personnel entered the flight deck through the L1 door, pulled back the smoke curtain, and observed smoke but no fire in the main cargo compartment. They opened all lower cargo compartments and found no smoke or fire. Several attempts were made to open the main cargo door by rotating the exterior lockpin handle. When it would not rotate, responders used a Halligan tool to force it, which caused the handle to spin freely and rendered it ineffective. ARFF personnel were not familiar with the accident airplane’s main cargo door, which adversely affected their ability to access the interior.

About 0040, ARFF personnel opened the right forward overwing hatch and observed flames just aft of the opening. Responders used a high-reach extendable turret with skin-penetrating nozzle (HRET/SPN) to pierce the fuselage. After unsuccessful attempts on the right side where the nozzle tip slipped, piercing operations on the left side were successful. The first fuselage burnthrough occurred about 0200 in the crown aft of the wings. The fire was reported under control about 0407.

During the response, the incident commander requested hazardous materials information. A UPS ramp supervisor provided the locations of the materials but indicated their specific identity was only contained in the NOTOC. About 35 minutes after landing, a firefighter reentered the cockpit, located the NOTOC, and provided it to the incident commander. UPS ground personnel at Philadelphia did not contact the UPS Flight Control Group to obtain the information electronically. The Safety Board concluded that UPS guidance on hazardous materials information retrieval and dissemination was inadequate.

### What the investigation found

Examinations of the recovered components revealed no evidence of any preexisting powerplant, structural, or system failures. The airplane's wiring was eliminated as a possible source of the fire.

No smoke or heat damage was observed inside the lower cargo compartments. In the main cargo compartment, containers 1 through 11 sustained minimal to moderate thermal damage. The heaviest fire damage occurred between cargo containers 12 and 17. The lowest point of fire damage to the fuselage occurred on the right side near cargo container 12. The Safety Board concluded that the fire initiated as a smoldering fire and most likely originated in container 12, 13, or 14. The exact origin and cause could not be determined due to the destruction of potentially helpful evidence.

Efforts to identify the shipments in the heavily damaged containers revealed several electronic devices that potentially contained secondary lithium batteries. No batteries were found that exhibited damage identifying a source of ignition. However, the Safety Board noted that testing and incident data indicate lithium batteries can pose a fire hazard.

The investigation reviewed the flight crew's use of checklists. The UPS DC-8 Aircraft Operating Manual did not contain specific procedures for responding to in-flight smoke, fire, or fumes in the absence of a cockpit warning. During troubleshooting, the flight engineer executed steps from the Fumes Evacuation checklist, which included setting the air conditioning packs to maximum flow. The Safety Board concluded that the increased airflow diluted the smoke, which inhibited its detection by either the smoke detection system or flight crewmembers, and provided the fire with additional oxygen.

The first indication of the fire was the odor detected about 20 minutes before the main cargo compartment smoke warning light activated. The Safety Board found that current certification test standards for smoke and fire detection systems do not account for the effects of cargo containers on airflow around the detection sensors and on the containment of smoke from a fire inside a container.

The accident airplane was not required to be equipped with a fire suppression system. The Safety Board concluded that the threat from cargo fires could be mitigated by the installation of fire suppression systems.

The investigation also noted that the L1 door was used as the primary emergency exit, but it was not required to have exterior instructional placards or a contrasting colored band outlining it. The Safety Board concluded that a floor level emergency exit would enable more efficient emergency egress for airplane occupants than cockpit window exits, and that exterior placarding would assist emergency responders.

### Probable cause

The National Transportation Safety Board determines that the probable cause of this accident was an in-flight cargo fire that initiated from an unknown source, which was most likely located within cargo container 12, 13, or 14. Contributing to the loss of the aircraft were the inadequate certification test requirements for smoke and fire detection systems and the lack of an on-board fire suppression system.