NTSB Factual Report

HISTORY OF FLIGHT

On May 2, 2002, at 0830 eastern daylight time, a Fairchild Dornier DO-328-300, N429FJ, operated by Atlantic Coast Airlines (ACA) d/b/a Delta Connection flight 6110, was not damaged after the crew reported a strong odor of smoke in the cockpit. The captain declared an emergency and landed without incident at Atlantic City International Airport (ACY), Atlantic City, New Jersey. The certificated airline transport pilot captain, commercial rated first officer, flight attendant, and 33 passengers were not injured. An instrument flight rules (IFR) flight plan was filed for the flight between Piedmont Triad International Airport (GSO), Greensboro, North Carolina, and La Guardia Airport (LGA), New York City, New York. Instrument meteorological conditions prevailed for the flight conducted under 14 CFR Part 121.

During an interview, the captain and first officer both said that they were established on a published arrival procedure into La Guardia and were about 20-30 miles east of Baltimore, Maryland, when air traffic control (ATC) instructed them to descend from 27,000 feet to 22,000 feet. During the descent, they began to smell a strong odor in the cockpit, which they described as something electrical burning. They did not know where the odor emanated from, and could not confirm that there was any smoke associated with the odor.

The odor dissipated, but returned just as strong a few minutes later. At this point, the crew said they donned their oxygen masks.

According to the captain, he thought that there was an in-flight fire and immediately declared an emergency. Shortly after declaring the emergency, he said that the air data computer (ADC) #1 and #2 screens displayed red "x's", and the information of the displays was intermittent. The flight director and the attitude heading reference systems (AHRS) #1 and #2 also went off-line. The engine parameters page on the engine indication and crew alerting system (EICAS) was empty, but the cautions page continued to load. The captain could not recall what cautions were posted, but said that there was no pattern to them.

While on approach to Atlantic City, the captain said the flight display screens returned to normal.

According to the first officer, he was flying the airplane. He said the first signs of electrical failures began when the autopilot disconnected, followed by the flight director. He said that his flight display screens never went blank, but were missing information. He saw a flight director fail warning light illuminated for a while, but it reset itself by the time they landed in Atlantic City. He said his attitude director indicator (ADI) turned blue. He also noticed there were red "x's" on the captain's displays for the flaps, ADC #1 and #2, airspeed and altitude. On the EICAS, the engine parameters page was empty, and he saw "empty shells and dashed lines." The caution page was full and continued to load. He said that he saw "lots" of 1's and 2's on the screen.

The first officer also said that due to the loss of flight display information, he flew the airplane on the stand-by instruments with the auto pilot off for the remainder of the flight. However, on approach into Atlantic City, he said the flight display screens had returned to normal.

A Federal Aviation Administration (FAA) inspector performed an examination of the airplane on the evening of the incident. According to the inspector the airplane was towed to Mid Atlantic Jet fixed base operator. ACA also dispatched two maintenance personnel to work on the airplane. The maintenance personnel performed a lightning strike inspection, partial airframe structural inspection, and a visual inspection for overheated wires and chaffing. All systems were checked with power on and both engines running. No discrepancies were noted during these checks.

The airplane was ferried to Dulles, Virginia, on May 4, 2002. One of the pilot's who ferried the airplane back to Virginia was the operator's supervisor of flight standards for the Dornier 328. According to the supervisor, the ferry flight was normal and there were no discrepancies noted with any of the airplane's flight systems or display units.

Examination of maintenance records indicated that the de-ice and ice detection system were also examined after the occurrence with no discrepancies noted. Additionally, the airplane was checked for structural damage and no discrepancies were noted. The airplane was returned to service.

METEOROLOGICAL INFORMATION

A National Transportation Safety Board meteorologist conducted a study of the weather conditions at the time of the incident. The Doppler Weather Radar images he used were generated from data downloaded from Unidata, and the airplane's radar track was plotted on the Weather Radar images. The data revealed that after declaring an emergency, the pilot started a right turn in order to fly away from the weather, which were VIP intensity levels 2 and 3. However, the airplane continued to make a 360 degree turn, and by the end of the complete circle, the airplane had turned back into weather of VIP intensity levels 4 and 5. At that point, the airplane was approximately 30 seconds away from entering VIP intensity levels 6.

AIR TRAFFIC CONTROL

A Safety Board Air Traffic Control (ATC) specialist reviewed the involvement and actions of ATC in this incident , and did not find any discrepancies in their handling of the emergency.

ADDITIONAL INFORMATION

On May 29, 2002, an ACA flight crew reported a loss of flight display information and odor while in cruise flight on the same airplane, N429FJ. Examination of the airplane's flight log revealed that the captain reported multiple failures during the flight. These failures included several EICAS messages, and a loss of all data on the first officer's #2 multi-function display (MFD) screen and #2 primary flight display (PFD). The data on these screens was replaced with red "x's". Also, the autopilot disconnected. The captain reported that these messages lasted for approximately 2 minutes, during which time there was static heard on the #1 communication frequency. After 2 minutes, the EICAS messages cleared up except for the "ice detector fail" caution.

The airplane landed without incident at the intended destination.

TESTS AND RESEARCH

The DC Junction Box (1VE panel), and Bus Power Control Unit (BCPU), and the #1and #2 integrated avionics computers were retained and examined.

The BPCU was examined and tested at Thales Avionics Electrical Systems under the supervision of the Bureau Enquetes - Accidents (BEA), with representatives from the Civil Aviation Authority-United Kingdom (CAA-UK) and Fairchild Dornier also present.

A review of maintenance records found no history of repairs at the manufacturer. Visual examination of the unit found traces of varnish on the J1A and J1B pins. Functional testing of the unit, including thermal heating, produced no discrepancies.

The DC Junction Box (1VE Panel), was designed to ensure the connection of power supplied to the distribution busses; connection of the APU to MAIN BUS 2; switching of power sources onto loads; protection of batteries against reverse current; control of generators or battery contactors; control of the APU contactor; primary protection of the power feeder lines by fuses; and passive protection of components housed within the junction boxes.

The DC Junction box was installed inside the pressurized airframe, under the cabin floor, between frame 23 and frame 24, in front of the main landing gear area. This area had ventilation air from the front through the rear of the airframe.

The DC Junction Box, was tested at Barfield Avionics, Miami, Florida, under the supervision of the Safety Board. The initial inspection revealed a missing fuse holder and 11 missing washers and bolts. During functional testing, the unit was found to be slightly out of tolerance on the 3PC Current Sensor. The sensor was replaced and the unit was tested with no discrepancies found.

During the testing of the units, Barfield provided general information on their experience repairing the DC Junction Box from the Fairchild Dornier 328-300. Over the course of the last 3 years, 377 units had been sent to Barfield for test/repair/overhaul. Fairchild-Dornier had submitted 159 (42%) of these units as a warranty service for some customers. All of the units sent to Barfield were sent by American operators and break down as follows:

PSA Airlines - 64 units

Astral Aviation (Skyways) - 28 units

Atlantic Coast Airlines - 124 units

Ozark Airlines - 2 units

According to information provided by Fairchild-Dornier at the time of the testing at Barfield, a total of 219 of the 328-series aircraft had been built (turboprop and jet). Nineteen of these aircraft were delivered to Chinese operators and 21 were still in the factory leaving 179 aircraft operating in the US and Europe.

This aircraft was equipped with a Honeywell Primus 2000 avionics package, which consisted of two integrated avionics computers (IAC). These units processed and displayed flight data on five display units (DU). IAC-1was powered from the DC essential bus and controlled display units 1, 2 and 3, the captain's primary flight display (PFD), the captain's multi-function display (MFD), and the engine indicating/crew alerting system (EICAS), respectively. IAC-2 was powered from DC Bus-2 and controlled DUs 4 and 5, the first officer's PFD and the first officer's MFD, respectively. The bus controller controlled a connection between IAC-1 and IAC-2 and allows the IACs to share information with each other.

The Safety Board's Systems Group convened July 22-23, 2002, at Honeywell Corporation in Phoenix, Arizona, and examined these units.

Prior to testing IAC-1, the crew alerting system (CAS) fields were downloaded at the Honeywell Technical Facility in Wichita, Kansas, and the IMT fault codes were downloaded later in Phoenix, Arizona. The unit was functionally tested in accordance with the Honeywell Test Specification IT7017300-VAR, Revision AY, which was the same test procedure used to certify the unit for operational use. No discrepancies were noted. The cover was removed and the interior was examined with no noted discrepancies.

The CAS fields were not downloaded from the IAC-2, but the IMT fault codes were downloaded during the examination. The unit was functionally tested to the above specification with no noted discrepancies. The cover was removed and the interior examined and no discrepancies were noted.

This first officer's PFD was functionally tested in accordance with Honeywell Test Specification IT7014300, Revision G, which was the same test procedure used to certify the unit for operational use. No discrepancies were noted.

As a result of the investigation, no failure could be identified that would have caused the loss of flight displays. In addition, the manufacturer reviewed the design of the electrical system and could not identify a design failure.

NTSB Probable Cause

The partial loss of flight display information for undetermined reasons.