# NTSB LAX94IA206: Boeing 737-209, N804AL, Honolulu, HI, April 27, 1994 - Type: NTSB incident investigation - Classification: Incident · Minor injuries · Incident investigation · Final report - Date: April 26, 1994, 19:42 local (Apr 27, 1994, 05:42 UTC) - Place: Honolulu, HI - Location: 21.3816° N, 157.8357° W: Placed by OpenAirDocs from NTSB’s distance and direction from DANIEL K INOUYE INTL (HNL), within about 2 miles (OpenAirDocs) - Nearby events: https://openairdocs.org/map.md?lat=21.3816&lon=-157.8357&mi=10 - Phase of flight: [Approach](https://openairdocs.org/ntsb-phases/500) (OpenAirDocs' grouping) - Highest injury: Minor injuries - Injuries: 1 minor, 58 uninjured - Status: Completed, report March 27, 1995 - Report: Approved by Office Director - NTSB case key (mKey): 28561 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=LAX94IA206 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/28561/pdf - Page: https://openairdocs.org/ntsb/LAX94IA206 ## Probable cause The failure of the battery transfer relay resulting in multiple system failures. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - Airframe/component/system failure/malfunction, approach - electrical system,electric relay - failure,total (cause) - Miscellaneous/other, taxi - from landing - fuselage,crew compartment - smoke - evacuation - initiated, pilot in command ## Analysis On approach, the crew lowered the landing gear, but noticed none of the gear position lights were illuminated. Prior to landing, the captain found both the public address and interphone to be inoperative. A visual approach was performed with a normal touchdown. During rollout, the crew discovered that the thrust reversers would not deploy. After turning off the runway, the flight attendants began to smell smoke. The captain stopped on the taxiway and initiated an emergency evacuation. One passenger received a minor sprain while using the emergency slide. An inspection revealed that a multiple system loss had occurred due to the 28-volt DC battery bus going off-line. The condition was duplicated during troubleshooting and the failed part was identified as a battery transfer relay (R2). The source of the on board smoke was not identified. ## Factual narrative On April 26, 1994, at 1942 Hawaii standard time, one passenger sustained minor injuries during a slide evacuation of Aloha Airlines flight 289, at Honolulu, Hawaii. The aircraft, a Boeing 737-209, N804AL, experienced multiple system failures during the landing approach and the evacuation was prompted by smoke entering the cockpit and cabin. The remaining 53 passengers and five crew members were not injured. The aircraft was owned and operated by Aloha Airlines, Inc., and was on a scheduled domestic passenger flight under 14 CFR Part 121 of Federal Aviation Regulations. Visual meteorological conditions prevailed at the time and an IFR flight plan had been filed for the operation. The flight originated from Kona, Hawaii, at 1905 on the day of the incident. According to the flight crew, during a visual approach into Honolulu International airport, the crew lowered the landing gear approximately 7 minutes from runway 4R. The gear extension appeared to be normal, but neither the red nor green position lights illuminated. System evaluation procedures revealed that the press-to-test function of the gear lights still operated; however, the master caution system was found to be inoperative. The manual gear extension system was employed with no noticeable change or indication. The first officer went back to the cabin to check the main gear visually, but because he was not familiar with the sight location in this configuration, could not locate the view port on the cabin floor. The captain then elected to do a flyby on runway 4R at 1,000 feet above ground level (agl). The tower was unable to confirm that the gear was down. The crew then attempted another flyby on runway 8L at 800 feet agl, and both the tower personnel and the crew of another aircraft on the ground were able to confirm that the gear was down. The captain then attempted a public address call to the passengers and an interphone call to a flight attendant, but both systems were also found to be inoperative. The captain did not declare an emergency, but requested that airport emergency equipment be prepositioned prior to landing. A visual approach was performed with a normal touchdown. During rollout, the crew discovered that the thrust reversers would not deploy. The aircraft was stopped using brakes and spoilers without further difficulty. After turning off runway 8L onto taxiway alpha en route to the gate, the flight attendants noticed what was described as a "burning odor." One attendant opened the cockpit door and informed the captain of the smell. The captain reported that he had also noticed the odor. As the flight attendant opened the door to the cockpit, the smoke alarm went off in the forward lavatory. The flight attendant opened the door to the lavatory, but found no smoke visible inside. As the same attendant looked toward the rear of the aircraft, he noticed there was hazy smoke accumulating in the mid-to-aft portion of the passenger cabin. During this time, the attendant reported that all the lights had gone out in the cabin. The captain stopped on the taxiway and instructed the crew to initiate an emergency evacuation. The evacuation was conducted with the assistance of the captain and first officer, using the emergency slides located at the forward service and entry doors. One attendant reported that after the doors were opened the smoke dissipated. Another attendant reported that the smoke alarm in the aft lavatory had also sounded during this time. The evacuation proceeded normally with the exception of one passenger who received a minor sprain while using the emergency slide. That passenger was treated at the scene and released. There were no injuries as a result of the events prior to the evacuation. The crew also reported that while inbound to Honolulu the autopilot had disengaged and could not be reengaged. There was a computer flag reported on the captain's ADI. The circuit breakers were recycled without effect. Investigation after landing revealed that the multiple system loss was due to the 28-volt DC battery bus going off-line. The condition was duplicated during troubleshooting and the failed part was identified as a battery transfer relay (R2). The source of the on board smoke was not identified. All of the inoperative systems were identified as being powered by the battery bus. The aircraft operations manual does not specify a troubleshooting procedure for identifying a bus failure or multiple system electrical failure. There are no cockpit indications that directly identify a bus failure or multiple system failure. The Boeing representative reported that when multiple systems are lost, the loss of a bus should be a reasonable conclusion; however, none of the current checklists relate to this possible condition. He also stated that there is no procedure that would enable the flight crew to restore power to the effected systems once bus failure has been experienced. A review of Federal Aviation Administration (FAA) safety data reports for the Boeing 737 aircraft failed to reveal any prior instances of relay or bus failures. Boeing reported two prior incidents, in 1971 and 1988, in which the battery bus lost power due to the failure of the R-1 battery relay. The failures were attributed to high resistance in the relay contact. The source of the resistance was identified as contact surface contamination caused by potassium bicarbonate residue. The contamination occurred during the manufacturer's cleaning process. The surface contamination resulted in a voltage drop which then allowed the bus to go off-line. Boeing reported that the relay part manufacturer implemented manufacturing and process improvements to prevent cleaning material from contaminating the contact surface. There have been no reported discrepancies with R-1 relays manufactured after April 26, 1988. ## Aircraft - Registration: [N804AL](https://openairdocs.org/deregistered/N804AL-2004-06-25), registration cancelled 2004-06-25, S/N 21719, built 1978 (OpenAirDocs) - Reported make and model: BOEING 737-209 - Registry model: [Boeing 737-2Q9](https://openairdocs.org/model/boeing-737-2q9) (registry code 138448M) (OpenAirDocs) - Registry engine: [Pratt & Whitney JT8D-9 series](https://openairdocs.org/engine/pratt-whitney-jt8d-9-series) (registry code 52048, turbo-jet) (OpenAirDocs) - Category: Airplane - Serial number: 21719 - Airframe hours: 34431 - Engines: P&W JT8D-9A 14500 lbs thrust turbo jet - Damage: No damage - Flight: Part 121 - Operator: Aloha Airlines, Inc., doing business as Aloha Airlines, Inc. - Registered owner: Gatx Capital Corp. - Airworthiness certificate: Standard, Transport - Last inspection: Continuous airworthiness, April 17, 1994, 48 hours before - Departed: KOA, KONA, HI - Destination: HNL, HI - Flight plan: IFR - Airport: HNL, Honolulu International, runway 8L, 12,357 × 200 ft, asphalt ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 49; airline transport; airplane ratings: single-engine land, multi-engine land; instrument ratings: airplane; medical: class 1, valid medical--w/ waivers/lim; seat: left; flight hours: 9,500 total, 7,500 in this make and model, 3,800 as pilot in command, 150 in the last 90 days, 50 in the last 30 days, 5 in the last 24 hours ## Weather - Conditions: Visual (VMC), Dusk - Wind: 60° at 9 knots - Visibility: 15 statute miles - Lowest ceiling: none - Temperature: 75 °F, dew point 66 °F - Altimeter: 30.00 inHg - Observed at: HNL, 7 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 19940426013729I](https://openairdocs.org/incident/19940426013729I), Apr 26, 1994: Boeing 737281, Honolulu, HI. Electrical failure on approach. Thust reversors ould not deploy. Los of all systems. 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.