Executive Summary
This paper studies the cause of the accident that occurred in 1988 involving Aloha Airlines flight 243. The airplane was flying passengers from Hilo to Honolulu. The craft experienced explosive decompression that left one flight attendant dead and many other injured. Several human mistakes led to the accident including the over-use of the craft which was 19 years old when the accident occurred. Safety policies and procedures are attributed to the accident. The study explores what might have caused the accident and the aftermath of the accident on safety policies.
Background
Airplane History
Based at the Honolulu International Airport, Hawaii, an Alahola Airlines Boeing 737 was scheduled for a number of inter-island flights on April 28, 1988. The flights were to be conducted under Code of Federal Regulations (CFR) Title 14 Part 121. The ill-fated plane was B737-200 Line number 152 and operated as flight 243. The craft was 19 years old when it crashed. It had accumulated 35,500 hours in flight with 89,700 flight cycles. Cycles are the pressurization between take-offs and landings. The cycle was the second highest in the world. When the crash occurred, the plane was en-route from Hilo to Honolulu. The plane experienced structural failure and an explosive decompression at 24,000 feet off the ground.
Early Morning Checks
A first officer and a captain had been assigned to make the first six flights of the day. A first officer had been planned to take over and complete the remainder of the day’s schedule. At the Aloha Airlines Operations Facility, the first officer checked in at around 0500hrs with the dispatch office. He familiarized himself with the operations flight paperwork and proceeded to the parking apron. He performed pre-flight procedures required by the company. The procedure is supposed to be carried out before the first flight of the day. The craft maintenance log released had been signed indicating there were no obvious discrepancies according the officer. He proceeded to prepare the cockpit for the preflight external portion. It was still dark when the officer performed the visual inspection on the exterior of the plane. The apron was however lighted. There was nothing unusual that the officer noticed hence was satisfied that aircraft was in good condition for flights (Aloha.net 1).
Normal Flights
At about 0510hrs, the captain checked in for duty. Upon completion of the pre-departure duties at the dispatch, he proceeded to the aircraft. There were three round-trip flights from Honolulu through Hilo, to Maui and Kaual. The crew reported that during all the six flights, the plane systems performed normally as expected. The flights were uneventful. Visual exterior inspections by the crew were not mandatory as per Federal Aviation Administration hence none was performed in between flights.
Change-over
The scheduled first officer took over at about 1100hrs for the rest of the day. The crew made flights between Honolulu to Maui then to Hilo. There flights were uneventful just like the previous ones in the morning. There were no abnormalities in terms of power-plant, system or structural. The pilot neither left the aircraft on arrival at Hilo nor did the crew perform any visual inspection on the exterior as they were not required to do so (Aloha.net 1).
The normal schedule required flight 243 to depart from Hilo Airport to Honolulu. The airplane left the airport at 1325hrs. There were two pilots, three flight attendants, a Federal Aviation Authority air traffic controller and 89 passengers aboard the flight. The FAA controller was seated in the cockpit in the observer seat. Nothing peculiar was observed when the passengers were boarding, when the engine started, during taxi or even when the airplane took off. The alternate landing airport was listed as Maui. Flight 243’s route was from Hilo to Honolulu.
First Officer
The first officer was in charge of the take off from Hilo. The non-flying pilot duties were conducted by the captain. The first officer did not recall engaging the auto-pilot during take-off or the flight (Aloha.net 2). The meteorological conditions were appropriate for take-off as visibility was good. However, there was neither airman’s meteorological information (AIRMET) nor significant meteorological information (SIGMET) advisories valid for the area the flight route was scheduled to take.
During the climb-out and departure, none of the crew members noted any unusual occurrences.
The Accident
It was not until the airplane was leveled at 24,000 feet that both pilots heard a strident applaud followed wind noise right behind them. The first officer was jerked backward. Debris which included pieces of gray insulation floated in the cockpit. The cockpit entry door was no longer there and the blue sky could be seen. The first-class ceiling had been ripped-off according to the captain.
Responsibility
On realization that there was danger ahead, the captain swiftly took over the airplane’s controls. According to the captain, the aircraft attitude was rolling slightly right and left. The controls for the flight felt loose as the captain revealed.
The captain, the first officer and the air traffic controller realized there would be a decompression hence put on oxygen masks. The captain initiated an emergence descent. The captain recaptured that he opted to extend the speed brakes. He indicated that the airspeed during the descent was 280 to 290 knots. The pilots were forced to use hand signals due to ambient noise. According to the first officer, at some point when the pilot was making the emergency descent, the rate of descent was 4,100 feet per minute. The passenger oxygen switch was actuated by the pilot during the descent. However, oxygen manual tee handle for passengers’ oxygen was not actuated (Aloha.net 2).
Decompression
All the passengers aboard were seated when the decompression transpired. The signal for the belt seat was illuminated. The number one flight attendant was allegedly standing at row five seats. Immediately the decompression occurred, the flight attendant was swept from the cabin. The passengers’ observation was that the flight attendant went through a hole on the left side of the fuselage from the cabin. At row 15/16 was standing the second flight attendant. She sustained minor injuries upon being thrown to the floor. She was able to eventually crawl to down the aisle seeking to offer assistance calm the terrified passengers. Standing at row two was the third flight attendant. Debris that was floating in the fuselage struck her in the head sending her to the floor. She suffered severe head cuts and other serious wounds.
Communication
The transponder was turned by the first officer to emergency code 7700. She tried to alert the Honolulu Air Route Traffic Control Center that flight 243 was diverting to Maui. She said she did not hear any radio transmissions due to the intense noise in the cockpit. She hence was not sure whether the Honolulu ARTCC received or heard the communication. The initial communication by the first officer was not received by the Honolulu ARTCC. However, the controller for flight 243 stated that he observed the emergency code 7700. The transponder returned approximately 23 nautical miles south-east of the Kahului Airport, Maui. Severally, the controller made attempts to communicate with flight 243 without any forthcoming success (Aloha.net 2).
The first officer opted to switch the radio frequency to the Maui Tower. At this point, the airplane had just descended through 14,000 feet. Declaring an emergency, she informed the control tower that there was rapid decompression. She highlighted the need for emergency equipment. The tower responded and initiated emergency notifications going by the report of decompression from the first officer. This was about 1348hrs. Via the direct hotline, the local controller directed the specialist at the clearance delivery position at the Maui Tower notified the airport’s firefighting and rescue personnel. The communication was that flight 243 was inbound due to an emergency emanating from decompression. The left side of the runway was taken up by rescue vehicles. Upon notification through the local 911 number, ambulance service was available from the nearby community at the Maui Airport. At that time, the control tower personnel did not find it necessary to alert the ambulance service considering the nature of the emergency.
The first officer was instructed by the control tower personnel to switch to Maui Sector transponder code. This was meant to facilitate the identification of the flight. She was also required to indicate to the local Air Traffic Controller facility that flight 243 was being controlled by the Maui air traffic controller facility. She switched the transponder as directed. However, the flight 243 was operating clear of the local controller’s radar authority of around 13 NMI. The local controller directed the first officer to switch to 119.5 Mega Hertz (Aloha.net 3). This is the approach frequency. It was meant to enable the approach controller to monitor the flight. However, the flight was not heard although the request was acknowledged. The first officer chose to continue transmitting on the local control frequency.
Crash-Landing
She informed the local controller that they could not communicate with the flight attendants and they would need assistance especially for the passengers upon landing. This did not compel the controller to make an ambulance request. The first officer did not indicate the fuel load but furnished the local controller the passenger count on the flight. The chief of the emergence response team requested the local controller for the fuel load information. The local controller did not make any further request of the fuel load from the first officer. This was about 1353hrs (Aloha.net 3).
The captain began slowing the aircraft when it was approaching 10,000 feet mean sea level (msl). The ATC speed limitations require the maneuver as a routine operations practice. He removed his oxygen mask, retracted the brakes and gradually turned towards Maul’s runway 2. The flight crew could now communicate verbally at 210 knots IAS. The command to lower the flaps was given by the captain. Flaps 1 was first selected then flaps 5. The aircraft started to become uncontrollable when they attempted to engage beyond flaps 5. Instinctively, he chose to continue with the landing with flaps 5. When the captain attempted to reduce the speed below 170 knots IAS, the airplane became less controllable. He chose to approach and land at 170 knots.
Equipment Failure
The attempt by the first officer to use an on-board interphone and the public address to communicate with the flight attendants did not give any response. The captain commanded the flight officer to lower the landing gear in the approach pattern at the normal point. The main gear displayed down and locked. There was no light illumination for the nose gear position. The green light indicator associated with manual nose gear did not illuminate after selection either. The unsafe indicator light of the landing gear did not illuminate. The manual nose gear handle was placed down after another manual attempt to complete the gear extension practice. The center jump seat was occupied hence no attempt was made to utilize the nose gear down-lock viewer. This was unnecessary as the landing was urgent according to the captain (Aloha.net 3).
The first officer at 1355hrs communicated to the tower that they would not be having a nose gear hence they would need all the available equipment. The captain determined that the first engine had failed when he heard a yawning motion as he attempted to advance the power levers to maneuver for the approach. The airplane was cruising at 170 to 200 knots IAS as he attempted to start the engine by placing the start switch of number 1 to the ‘flight’ position. This did not give the anticipated response. 4 miles out on the approach, there was established a normal descent profile (Aloha.net 4).
Kahului Airport runway 02
At Maui’s Kahului Airport runway 02, flight 243 landed at exactly 1358:45. The captain managed to make a normal touchdown and landing rollout. He attributes stopping of the aircraft on the runway to using brakes and number 2 engine thrust reverser. The flaps were extended forty degrees as required for an emergency evacuation as part of the rollout. The emergency evacuation was accomplished.
Accident Summary
Technical Summary
The National Transportation Safety Board (NTSB) is an autonomous Federal agency mandate with promoting transportation safety, assisting victims of transportation accidents and determining the probable cause of transportation accidents (Ntsb/AAR-89/03 1). The NTSB made a report based on the airplane accident that occurred on April 28, 1988 at Kahului, Hawaii, USA.
The report revealed that the accident was probably caused by failure of the Aloha Airline maintenance program. The program did not detect the presence of noteworthy fatigue and dis-bonding damage on the aircraft. Ultimately, damage led to the separation of the fuselage upper lobe and the lap joint S-10L failure.
The management of Aloha Airlines also contributed to the accident. This was through failure to properly supervise the maintenance force of the airline.
The FAA also contributed to the accident by demanding Air worthiness Directive 87-21-08 inspection. The directive would have seen the airplane’s flap joints inspected as proposed by Boeing Alert Service Bulletin SB 737-53A1039.
The lack of termination action after the detection of early production difficulties in the Boeing 737 cold bond lap joint also contributed to the accident. The difficult in producing the lap joint resulted in corrosion, premature fatigue cracking and low bond durability. The FAA failed to make the proper production of cold bond lap joint a requirement. Boeing did not take the initiative to stop the production (Ntsb/AAR-89/03 1). The engineering design was poor and did not consider continuous inspection of the B-737 worthiness.
Lap joints hold two overlapping sheets of metal on the fuselage together. The design of the 737 is meant to decompress safely even with a 40 inch crack on the craft’s skin. Instead of an explosive decompression, the crack is supposed to release internal pressure in a controlled form (Stroller 1). However, in the case of flight 243, the fuselage tore about 18 feet. This translates to numerous cracks caused by fatigue which passed undetected. The fuselage was weak due to the airplanes age and continuous use. The adhesive that was supposed to have held the lap joint failed to prevent water from getting between the sheets. This caused corrosion further weakening the lap joint.
Decision Making Summary
A passenger later said that when she was boarding flight 243 at Hilo through the jet bridge, she had seen a longitudinal crack on the fuselage. The crack was along the S-10L lap joint in the upper row of rivets. This was halfway between the edge of the jet bridge hood and the cabin door. However, she had not mentioned the observation to the flight crew or the ground personnel (Aloha.net 4).
The first officer and the captains did not notice the cracks on the fuselage. The flight crew also did not. This is associated with making assumptions that because the airplane did not indicate any abnormalities the previous day, then it ought to mechanically fit.
The maintenance personnel failed to diligently perform their duties. Lap joints are known to experience pressure due to their nature of holding two pieces of metal sheet together. The maintenance should have been keener when going through the routine with making any assumptions.
The Airline management failed to recognize that the airplane had outlived it life-span and ground it. The airplane had made more than 75,000 trips it was initially designed to sustain (Pediaview.com 1)
Outcome
The accident changed the maintenance practices for aged planes. Old aircrafts are not safe to fly according to Stoller (1). This is despite maintenance being done. The Airline no longer uses the 737-200 ‘basic’ which was involved in the accident. The company fleet uses 737-200 ‘advanced’ which is manufactured differently. The accident prompted the FAA to initiate a program to vigilantly inspect aging planes (Delisi 12).
The FAA has insisted on the human aspect of carrier maintenance and inspection. The maintenance personnel and supervisors should be well trained before certification. The training includes repair procedures and training. The FAA also insists on inspectors and mechanics qualification to be beyond any doubt. In 1989, the FAA reviewed the 25.571 for retroactive requirement for old planes and newly certified crafts (Delisi 12). The two pilots were not disqualified. They remained with the airline until the airline stopped passenger operations.
Summary Analysis
There would have been specific emphasis on fuselage lap joints and multiple fatigue areas. Uninterrupted maintenance procedure should be done as opposed to the airline’s early morning installments. Old aircrafts should not be used beyond the intended duration of use. Regular inspection and maintenance cannot guarantee safety of an aircraft.
Works Cited
Aloha.net. “Aircraft Accident Report- Aloha Airlines, flight 243, Boeing 737-200, – N73711, near Maui, Hawaii- 28 April 1988” (1989). Web.
Cooper, Ann and Rainus, Sharon. “Mimi Tompkins-Aftermath”. Stars of the Sky, Legends All: Illustrated Histories of Women Aviation Pioneers. Minneapolis, MN: Zenith Press (2008): 138–140. Print.
Delisi, John. “Aloha Airlines Flight 243 Accident Review” (n.d). Web.
National Transportation Safety Board. “Aircraft Accident Report- Aloha Airlines, flight 243, Boeing 737-200, – N73711, near Maui, Hawaii- 28 April 1988” (1989). Web.
Ntsb/AAR-89/03. “Aloha Airlines, flight 243, Boeing 737-200, N73711, near Maui, Hawaii, April 28, 1988″. National Transportation Safety Board. Web.
Pediaview.com. “Aloha Flight 243” (n.d). Web.
Stoller, Gary. “Engineer fears repeat of 1998 Aloha jet accident” (2001). Web.