History of the Flight

AVA052 departed Bogota International Airport at 1310.  The flight made a scheduled intermediate stop at Jose Maria Cordova Airport near Medellin, Colombia at 1404 and prepared for departure to JFK.  There was no change of flight crew.  The crew consisted of a captain, first officer, and flight engineer (second officer).  The flight departed Medellin at 1508.

The flight plan was an oceanic route north toward the East Coast of the United States.  The route through U.S. airspace included Dixon, North Carolina, then to Norfolk, Virginia, direct to Sea Isle, New Jersey, and on to JFK.

Three Holding Periods

The weather over the East Coast of the U.S. was poor with conditions of overcast and rain over the coastal Mid-Atlantic states and New England.  As the flight proceeded northward it was placed in holding three times by air traffic control (ATC).  The first period of holding was over Norfolk for 19 minutes, from 1904 to 1923.  The flight was placed into holding a second time near Atlantic City for 29 minutes, from 1943 to 2012.  The flight was placed into holding a third time, 39 miles south of JFK, for 29 minutes from 2018 to 2047.

Within the third hold period ATC advised AVA052 to expect further clearance at 2105.  The first officer responded, "…ah well I think we will need priority we’re passing [unintelligible]."  The investigators determined that the first officer was making all calls to ATC. 

ATC inquired, "…roger how long can you hold and what is your alternate [airport]?"  At 2046:03 the first officer responded, "Yes sir ah we’ll be able to hold about five minutes that's all we can do."  The controller replied, "…roger what is your alternate?"  The first officer responded, "ah we said Boston but ah it is full of traffic I think."  The controller said, "…say again your alternate airport?"  The first officer responded, "it was Boston but we can't do it now we, we, don't, we run out of fuel now."

 

 

Low Fuel

ATC responded to the first officer's request for priority by allowing the flight to depart the third holding period at 2047:00 and proceed toward JFK.  The flight was given routine ATC service including descents to lower altitudes and heading changes, to place it in sequence with airplanes that were en route to instrument flight rules (IFR) approaches to JFK. 

At 2056:16 ATC advised the flight of a windshear.  The first officer acknowledged receipt of the windshear advisory.  The flight continued to get routine ATC service, including several heading changes, and further descent clearances to 3,000 feet, and finally to 2,000 feet.

The following conversations in Spanish occurred in the flight deck.  At 2109:21 the first officer stated, "they accommodate us ahead of an--.”  A few seconds later the captain said, "what, " and the first officer replied, "they accommodate us.”  The second officer said, "they already know we are in a bad condition.”  Then the captain replied, "no they are descending us.”  The first officer reported, "one thousand feet.”  The captain said, "ah yes."  Then the second officer stated, "they are giving us priority."

Windshear and Missed Approach

The crew conducted an ILS approach on JFK runway 22L.  The flight was number three to land following a Boeing 727 that was on a 9 mile final approach.  Starting at 2117:17 the JFK tower confirmed their airspeed (140 knots) and requested that AV052 increase speed 10 knots.  The first officer responded, "okay one zero knots increasing."  The captain replied, "tell me things louder because – I'm not – hearing it."

 

 

They captured the glideslope, lowered the landing gear and flaps, and began the landing checklist.  At 2119:58, JFK tower cleared AV052 to land.  The captain said, "give me fifty," and shortly thereafter he said, "are we cleared to land no?"  The first officer responded, "yes sir we are cleared to land."  The first officer said, "localizer to the left slightly below glideslope."  Then the second officer said, "stand by flaps fifty landing checklist complete."  And the captain said, "flaps fifty now."  The second officer said, "fifty green light final set."  At 2120:48 the first officer said, "below glideslope."

At 2122:05, AVA052 was about 3.2 miles from the approach end of runway 22L.  Fifty two seconds later the first officer said, "this is the windshear."  Then the second officer said, "glideslope."  A few seconds later the first officer said, "glideslope," "sink rate"; and "five hundred feet."

Between 2123:08 and 2123:23 (CVR), there were 11 "whoop pull up" voice alerts from the airplane's ground proximity warning system (GPWS).  Between 2123:25 and 2123:29, there were 4 "glideslope" deviation alerts from the GPWS.  At 2123:23, the captain asked, "the runway where is it?"  At this time, AVA052 was 1.3 miles from the approach end of runway 22L at an altitude of 200 feet.  The first officer said, "I don't see it I don't see it."  The captain replied, "give me the landing gear up landing gear up."  The AVS052 ILS missed approach figure shows the profile view of the approach path and go around.

AVA052 executed a missed approach, advised the tower, and were directed to call ATC approach.  At 2125:07, the New York (NY) TRACON controller replied to the radio call, "Avianca zero five two heavy New York good evening climb and maintain three thousand."

Fuel Exhaustion

At 2125:08, the captain said, "advise him we don't have fuel."  The first officer made the radio call, "Climb and maintain three thousand and ah we're running out of fuel sir."  The captain asked, "did you already advise that we don't have fuel?"  The first officer replied, "Yes sir.  I already advise him hundred and eighty on the heading we are going to maintain three thousand feet and he's going to get us back."  The captain replied, "okay."

At 2126:35, the NY TRACON controller stated, "and Avianca zero five two heavy ah I'm going to bring you about fifteen miles northeast and then turn you back for the approach.  Is that fine with you and your fuel?"  The first officer replied, "I guess so thank you very much."

At 2129:11, the first officer asked, "Ah can you give us final now…?"  The NY TRACON controller responded, "…affirmative sir turn left heading zero four zero."  The controller stated, "Avianca fifty two climb and maintain three thousand."  The first officer replied, "ah negative sir we just running out of fuel we okay three thousand now okay."  The controller responded, "Okay turn left heading three one zero sir."

The captain called to set flaps 14, and the controller directed AVA052 to heading 360, both of which were confirmed completed.  At 2131:01, the controller stated, "okay you're number two for the approach I just have to give you enough room so you make it without ah having to come out again."

At 2131:22, the captain asked, "three sixty no?"  The first officer replied, " three sixty."  The captain said, "flaps fourteen."  About a minute later the flight was instructed to turn left to a heading of 330.

At 2132:14, the first officer said, "three three zero the heading."  Twenty five seconds later the second officer said, "flame out flame out on engine number four."  The captain replied, "flame out on it."  The second officer then said, "flame out on engine number three essential on number two or number one."  The captain stated, "show me the runway."

At 2132:49, the first officer radioed, "…we just ah lost two engines and ah we need priority please."  The controller then instructed AVA052 to change headings to 250 and advised the flight that it was fifteen miles from the outer marker and cleared for the ILS approach to runway 22L.  The first officer replied, "two five zero."

At 2133:04, the captain stated, "select the ILS let's see."  A few seconds later the captain stated, "that no – that," and asked, "did you select the ILS?"

At 2133:07, the controller informed the flight, "…you're one five miles from the outer marker maintain two thousand until established on the localizer cleared for ILS two two left."  The first officer replied, "it is ready on two."  This radio transmission was the last clearance acknowledged by AVA052.

At 2133:24, the Cockpit Voice Recorder ended, due to a loss of electrical power resulting from the failure of the remaining engines.

At 2134:00, the controller asked AVA052, "You have ah you have enough fuel to make it to the airport?"  There was no response from the airplane. At about this time, AVA052 impacted on a hillside in a wooded residential area on the north shore of Long Island.  The starboard side of the forward fuselage impacted and fractured the wooden deck of a private residence.  There was no fire.

View the AVA052 Flight Path Animation below: 

 

 

Standard Emergency Phraseology

At the time of the accident, FAA Order 7110.65 provided guidelines to air traffic controllers on assisting aircraft in an emergency.  An emergency can be either a "distress" or an "urgency" condition as defined in the pilot/controller glossary.  A pilot who encounters a distress condition would declare an emergency by beginning the initial communication with the word "MAYDAY," preferably repeated three times.  For an urgency condition the word "PAN-PAN" should be used in the same manner.  The word "EMERGENCY" can also be used in place of "MAYDAY."

The first officer requested "priority" from ATC when AVA052 was in the third hold period and it was clear the hold was going to be extended until at least 2105.  He did not declare an emergency using standard phraseology so ATC interpreted this as a request to be removed from holding due to low fuel.  ATC did arrange to remove AVA052 from holding but proceeded to provide routine ATC service after that without any attempt to move the flight up in the landing sequence or suspend other traffic to allow an emergency landing.

Comparison of Minimum Fuel, Emergency Fuel and Reserve Fuel

FAA Information for Operators (INFO) 08004 provides an overview of these terms and how operators should interact with ATC to communicate their fuel situation.  Highlights of the basic definitions and discussion follow. See link below for more details on the definitions.

FAA INFO 08004 Comparison of Minimum Fuel, Emergency Fuel, and Reserve Fuel

 

 

The Aeronautical Information Manual (AIM) and the Pilot/Controller Glossary both provide the following definition, which states that, Minimum Fuel:

"Indicates that an aircraft's fuel supply has reached a state where, upon reaching the destination, it can accept little or no delay.  This is not an emergency situation but merely indicates an emergency situation is possible should any undue delay occur."

If, at any time, the remaining usable fuel supply suggests the need for traffic priority to ensure a safe landing, the pilot should declare an emergency and report fuel remaining in minutes.

Emergency Fuel

Although not defined in the AIM or Federal Aviation Regulations, the industry-wide connotation typically associated with the term "Fuel Emergency" is:

The point at which, in the judgment of the pilot-in-command, it is necessary to proceed directly to the airport of intended landing due to low fuel. Declaration of a Fuel Emergency is an explicit statement that priority handling (meaning immediate clearance to land with priority over other aircraft) by ATC is both required and expected.

Reserve Fuel

FAA fuel requirements for flight in IFR conditions state that:

"No person may operate a civil aircraft in IFR conditions unless it carries enough fuel (considering weather reports and forecasts and weather conditions) to-"

• Complete the flight to the first airport of intended landing;
• Fly from that airport to the alternate airport [if one is required]; and
• Fly after that for 45 minutes at normal cruising speed or, for helicopters, fly after that for 30 minutes at normal cruising speed.

Minimum Fuel State and Emergency Calls to ATC

The use of a portion of the reserve fuel is not, in itself a cause to declare a minimum fuel state with ATC. Regulations require reserve fuel to enable aircraft to maneuver, due to unforeseen circumstances. Many aircraft safely arrive at their destination having used a portion of the fuel designated as reserve. There is no regulatory definition as to when, specifically, a pilot must declare "Minimum Fuel" or a Fuel Emergency. Air carriers typically develop such guidance for their pilots and include it in their General Operations Manuals; such guidance generally falls along the following lines:

• Declare "Minimum Fuel" when, in your best judgment, any additional delay will cause you to burn into your reserve fuel.
• Declare a Fuel Emergency at the point at which, in your judgment, it is necessary for you to proceed directly to the airport at which you intend to land. Declaration of a Fuel Emergency is an explicit statement that priority handling (meaning immediate clearance to land with priority over other aircraft) by ATC is necessary and expected.

The investigation found that the Avianca Route Manual in use at the time of the accident had a definition of Minimum Fuel similar to that above. The crew did not declare either Minimum Fuel or a Fuel Emergency to ATC using standard phaseology.

Crew Resource Management (CRM)

Air carrier accident investigation experience over the past 40 years has indicated that most of the accidents were attributable not so much to a lack of individual technical proficiency as to shortcomings in resource management and leadership abilities by captains, and active team support by other flight deck crew members.  This experience has led to much greater emphasis on a team approach to training airline flight crews by most airlines.

This approach, generally known as CRM training, has gained significant support in the airline industry and among regulatory authorities.  CRM training is specifically designed to improve communication and teamwork among members of flight crews, and to foster the use of all the resources at their disposal.  FAA Advisory Circular (AC) 120-51 issued on December 1, 1989, provides guidance for the development of CRM training. It is linked here: AC 120-51

Flight crew Communications

The first indication that the flight crew had some concerns about weather, and possibly the fuel state occurred at about 2009.  At this time AV052 requested information about delays into Boston after being in holding for 26 minutes.  There was no further indication from the flight crew about AV052's fuel state until after the airplane had been in holding for 1 hour and 6 minutes on three separate occasions. 

When ATC issued a message to expect further clearance at 2105 the flight crew apparently finally realized that they had to commence an approach to JFK and therefore requested priority handling.  The Safety Board concluded that the flight crew had already exhausted its reserve fuel to reach its alternate by the time it asked for priority handling.  When asked a second time for its alternate, the first officer responded, "It was Boston, but we can't do it now."

Although the first officer had radioed at 2046:03, "Yes sir, ah, we'll be able to hold about five minutes, that's all we can do," the airplane did not have sufficient fuel to fly to its alternate.

The fuel state at the time AVA052 was cleared for approach to JFK was already critical for its destination.  To help ensure sufficient fuel to complete a safe landing, an emergency should have been declared in order to receive expedited handling.  The airplane exhausted its fuel supply and crashed 47 minutes after the flight crew stated that there was not sufficient fuel to reach the alternate.  This occurred after the flight was vectored for an ILS approach to the destination, missed the first approach, and was unable to complete a second approach. 

Because the CVR retained only 40 minutes of flightdeck conversations, the Safety Board could not determine whether the crew discussed the minimum fuel level that they should have onboard when commencing the approach, prior to leaving the last hold period.  However it was apparent to the investigators, from communications with ATC while holding (first, the expressed need for "priority" at about 2045 and second, the observations that the flight could hold only 5 minutes, and that they could not reach Boston only minutes later) that the crew was aware of, and concerned about the fuel problem.  Whether the captain, or first officer, or both, believed that these transmissions to ATC conveyed the urgency for emergency handling is unknown.

However, at 2054:40, when AVA052 was given a 360 degree turn for sequencing and spacing with other arrival traffic, the flight crew should have known that they were being treated routinely and that this situation should have prompted them to question the clearance and reiterate the criticality of their fuel situation.  At that time, they could have declared an emergency, or at least requested direct routing to the final approach in order to arrive with an acceptable approach minimum fuel level.

After the flight executed a missed approach to JFK at about 2123:28, the captain advised the first officer, "tell them we are in an emergency."  However, the first officer acknowledged an ATC altitude and heading instruction to the JFK tower controller, adding, "we're running out of fuel."  He did not use the word "emergency," as instructed by the captain, and therefore did not communicate the urgency of the situation.  Thus, the tower controller was not alerted to the severity of the problem.  When the tower controller advised AVA052 to contact the NY TRACON controller for vectors for a second approach, he did not advise the TRACON controller that AVA052 was running out of fuel.  However, when AVA052 contacted the TRACON controller, the first officer again stated, "…we're running out of fuel sir," after acknowledging a clearance to climb to 3,000 feet.

The tower controller did not follow up on the radio calls about running out of fuel. However, the TRACON controller turned the flight back onto a downwind leg and asked the flight if it could accept a base leg 15 miles northeast of JFK.  The first officer responded, "I guess so."

Shortly thereafter, at 2124:22, the captain again advised the first officer to, "advise him we have an emergency."  Four seconds later, the captain said, "did you tell him?" The first officer replied, " yes sir, I already advised him."  Further, at 2125:08, the captain said to the first officer, "advise him we don't have fuel."  He asked again, at 2125:28, "Did you advise him that we don't have fuel?"  The first officer again said, "yes sir, I already advise him…"

These flightdeck conversations indicate a total breakdown in communications by the flight crew in its attempts to relay the situation to ATC.  The accident may have been inevitable at that point, because the engines began to flame out only about 7 minutes later.  However, it is obvious that the first officer failed to convey the message that the captain intended.  The evidence strongly suggests that the captain was unaware at times of the content of the first officer's transmissions and that he did not hear or understand the ATC radio calls.  The investigators believed it more likely his limited command of the English language prevented him from effectively monitoring the content of the calls.  The investigators further believed that this deficiency might have been a factor in the accident, particularly if the captain believed that the first officer had adequately expressed the criticality of the fuel situation upon departure from the third holding period.

In summary, the investigators found that two key factors leading to this accident were:

• The flight crew's failure to notify ATC of their fuel situation during the third holding period in order to ensure arrival at the approach fix with an adequate approach minimum fuel level.
• The breakdown in communications between the flight crew and ATC, and among the flight crew members.

The Safety Board recommended that Avianca Airlines incorporate CRM training concepts into the training for all of its flight crews. 

Wreckage and Impact Information

The airplane impacted on a approximately 24 degree upsloping hill.  Based on ground scars left by the engines and airframe, the entire fuselage, with the exception of the flightdeck and forward cabin, came to a stop within 21 to 25 feet after impact.

 

 

The fuselage was found partially separated into three sections.  The flightdeck and forward cabin had broken away from the rest of the fuselage at the time of terrain impact and continued to move over the crest the slope, coming to rest about 90 feet forward of the main wreckage.  This section was significantly damaged, with seats and other cabin components lying on the ground, extending back to the main wreckage.

The main fuselage had come to rest, upright, on the upslope of the hill.  The forward end of this section extended over the crest of the slope.

 

 

Cabin Interior and Seat Condition

Interior furnishings, consisting of the galley, seats, seat belts, overhead bins, decorative panels and floor structure from the flightdeck/forward cabin fuselage section were found scattered along the wreckage path between the separated flightdeck/forward fuselage back to and into the fractured opening of the center section the cabin.  This fracture was just forward of the point where the leading edge of the wing mates with the fuselage.  Interior furnishings were also scattered along the wreckage path forward of the nose of the airplane, up to a point about 100 feet beyond the final resting point of the flightdeck and forward cabin section.

The interior of the flightdeck was found substantially damaged.  Four of the five flight deck seats (the three seats occupied by the flight crew, as well as one of the two observer seats, both of which were unoccupied) were lying outside the flightdeck.

There was substantial damage inside the overwing section of the cabin.  Interior furnishings, consisting of passenger seat units, overhead bins and decorative panels, were piled up outside the forward break in the fuselage.  There was a fracture of the longitudinal floor track, evidenced by a downward disruption of floor panels between two lateral floor beams.  The remainder of the cabin floor was generally intact but was displaced downward about 3 inches on the right side.  The inboard rear seat legs of 16 seat assemblies remained attached to the floor track in the overwing section (See cabin center section figure).  The outboard legs of their assemblies were fractured at the floor track.  These seats were found outside the cabin and forward of the overwing section.

Survivability

 

According to the lead flight attendant, seated in 2C, who survived with serious injuries, there was no warning to the cabin from the flightdeck regarding the low fuel status, loss of engines, or the impending emergency landing.  Therefore, passengers were not briefed on brace positions, other than during the preflight briefing, or on evacuation procedures.  However, after the failure of all four engines and generators, the ability of the flightdeck to communicate with cabin of the PA system would have been lost.

Seventy-two of the 74 passengers who survived sustained serious injuries.  These injuries consisted of multiple lower leg fractures and dislocations, head injuries, hip fractures, spinal fractures, and multiple lacerations and contusions.  The legs of passengers were believed to have impacted the lower seat back frames of seat units in front of them.  Simultaneously, passenger seats most likely collapsed and twisted downward and to the left, resulting in hip and spinal fractures.  As the impact sequence progressed, separation of the seats from their floor attachments pushed passengers forward into passengers, seats, and other wreckage debris, causing head injuries and lacerations.

It could not be determined where all the passengers were seated at the time of impact, because the airline only assigned seats to a small percentage of passengers.  Those passengers who had assigned seats stated that many of them moved freely about the cabin to sit with family and friends.  Therefore, passenger seat locations in relation to an individual injury diagram could not be developed with certainty in all cases.

The captain, first officer, and flight engineer died from blunt force head and upper torso trauma.  The captain and first officer seats had no shoulder harnesses installed.  On March 6, 1980, the FAA required all flightdeck seats to be equipped with combined seatbelts and shoulder harnesses; however, ICAO standards do not address these restraint systems.

Five of the six flight attendants were fatally injured as a result of blunt force injuries to the head, chest, abdomen, and limbs.  Three of the five flight attendants' locations could be established based on the statement of the surviving flight attendant.  One was seated in the L-1 one attendant seat, the second was in passenger seat 2A, and the third was in passenger seat 3C. Sixty-four adult passengers and one 4-month-old infant died as a result of blunt force injuries.

16g Seat Rule History and Avianca AVA052

The seats on AVA052 were known as 9g static load seats which were certified to Civil Aeronautics Regulations (CAR) 4b.260 (equivalent to current requirement 14 CFR 25.561). This was the standard in place at the time the airplane model received FAA type certification in 1959. The accident airplane was put into service in 1967. The more stringent 16g dynamic load seat rule (14 CFR 25.562) was put in place in 1986 after the Avianca Boeing 707 airplane was already in service with the airline. The 16g seat rule did not require existing airplanes in the U.S. fleet to be upgraded to meet the new standard. In addition, airplanes operated by non-U.S. carriers such as Avianca would not have been required to retrofit their airplanes to comply with the 16g rule unless directed by their national airworthiness authorities.

The Avianca accident in 1990 was one of many demonstrating that 9g seats do not assure protection to passengers or crew in a survivable crash. Evidence of poor seat performance during the AVA052 crash sequence includes:

1. Large numbers of seats broke loose from the otherwise intact but deformed floor structure and fuselage sections resulting in severe injuries or fatalities for nearly all occupants.
2. Seat frames fractured and detached from leg structures still attached to the floor structure.  Seat backs fractured and became detached from the seat frames. Seat belts failed. The unrestrained passengers and crew impacted airplane structure or were ejected from the airplane causing severe injuries and fatalities for nearly all occupants.
3. Seat tracks and seat attachment fittings fractured allowing seats to break loose from the airplane floor.
4. Seat rigidity and deformation led to injuries and impeded the ability of passengers and crew to evacuate the airplane.
5. Passengers sustained severe head injuries, lumbar spine, hip and leg fractures while seated in seats still attached to the floor structure.

 

 

A great deal of research went into the new 16g seat rule.  Poor seat performance such as that seen in AVA052 was studied in a number of accidents.  The new rule was tailored to prevent the poor seat performance seen during the AVA052 accident.
A few concepts are fundamental to the 16g seat rule:

1. Seats should stay attached up to point of fuselage breakup and have equivalent structural strength to the floor to which they are attached even when the floor is deformed during the accident sequence.
2. Seats should deform in a controlled manner such they that they absorb impact energy and minimize injuries to passengers.  But the seats should not deform so much that they block evacuation paths out of the airplane or prevent a person from exiting their seat.
3. Injury criteria should make for seat designs that provide a high level of protection from head, lumbar spine, and femur leg injuries.
4. Seat belt (and belt attachments to the seat) strength and deformation standards should be equivalent to the seats designed to the new dynamic standards.
5. The seats should protect occupants for two dynamic pulse load cases.   One is an all longitudinal 16g crash loading to simulate running off the end of a runway and impacting ground structure or a berm, for example.  The other is a 14g crash loading combining forward longitudinal and down loading to simulate a very hard landing.

This accident reinforced why the 16g dynamic seat standard was appropriate and a substantial benefit to passenger and crew safety in survivable accidents.

Provided is an example test video showing what happens to older 9g static type seats similar to those on AVA052 when subjected to the 16g dynamic requirement.  This simulates what happened to the seats during the AV052 accident.  Note the seats breaking loose from the floor, and the unrestrained occupants.

Video – Failure of 9g static seat subjected to 16g dynamic load test:

 

 

Here are videos of similar tests with seats designed to meet the new 16g seat requirement.  Note the dramatic improvement in seat performance. 

• Video – Example 16g dynamic seat test

 

 

• Video – Onboard example 16g dynamic seat test

 

 

The photo below shows one such success story accident explained in the section.

 

 

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The NTSB issued 24 findings as a result of the accident. The findings ranged from flight crew performance, air traffic management performance, and injuries related to the crash forces and crew seat features.

The complete text of the findings is available at the following link: NTSB Findings.

Further, the NTSB determined the probable cause to be:

"The probable cause of this accident was the failure of the flight crew to adequately manage the aircraft's fuel load, and their failure to communicate an emergency fuel situation to air traffic control before fuel exhaustion occurred. Contributing to the accident was the flight crew's failure to use an airline operational control dispatch system to assist them during the international flight into a high-density airport in poor weather. Also contributing to the accident was inadequate traffic flow management by the FAA and the lack of standardized understandable terminology for pilots and controllers for minimum and emergency fuel states. The Safety Board also determines that windshear, crew fatigue and stress were factors that led to the unsuccessful completion of the first approach and thus contributed to the accident."

The NTSB accident report is available at the following link: Avianca Flight 052 accident report

 

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The NTSB issued a number of recommendations as a result of the accident. The recommendations ranged from requiring standardized terms for emergency fuel communications, seat restraints for all occupants, to requiring crew resource management training. In addition, previous recommendations were classified in this report.

The complete text of the recommendations is available at the following link: NTSB Recommendations

 

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Certification regulations:

14 CFR 25.561 Emergency landing conditions
14 CFR 25.562 Emergency landing dynamic conditions
14 CFR 25.785 Seats, berths, safety belts, and harnesses

Operational regulations:

14 CFR 91.703 Operations of civil aircraft of U.S. registry outside of the United States
14 CFR 121.645 Fuel supply: Turbine-engine powered airplanes, other than turbo propeller: Flag and supplemental operations
14 CFR 121.621 Alternate airport for destination: Flag operations
AC 60-28 Advisory Circular: English Language Skill Standards Required by 14 CFR parts 61, 63 and 65
AC 120-51 Advisory Circular: Crew Resource Management Training

Air Traffic AC 120-51 Advisory Circular: Crew Resource Management Training regulations:

FAA Order 7110.65 Air Traffic Control Handbook

 

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Airline

The investigation found that Avianca did not provide CRM training to their flight and cabin crews. CRM training can enhance the ability to prevent and/or manage flight crew errors, and in maintaining continuity in flight crew performance of duties. The investigation also found that the airline did not require that all flight crew members speak English proficiently.
A news report at the time showed that the airline did not train its flight crews to use the word "emergency" when declaring a fuel emergency as they did not deem it necessary. A pilot at the airline said that words or phrases such as "priority" or "we are running out of fuel" should be sufficient.

Link to article "New Disclosure on Avianca Plane Crash", New York Times, June 21, 1990.

Pilot Culture

A news report at the time showed that pilots were reluctant to declare fuel emergencies for a number of reasons including being perceived as not up to normal pilot standards, receiving a formal write up on their record, and the inconvenience of filling out paperwork.

Link to article "Right Word is Crucial in Air Traffic Control", New York Times, January 29, 1990.

Air Traffic Control

The same report showed that air traffic controllers deemed keeping track of fuel level to be the pilot's responsibility. They stated that if a pilot needs immediate help, they need to declare that by contacting them using the term "fuel emergency." They further stated that they knew of pilot's reluctance to declare fuel emergencies so they would look for signs of distress in pilot's speech patterns.

Link to article "Right Word is Crucial in Air Traffic Control", New York Times, January 29, 1990.

 

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• The investigation found that the flight crew was fatigued.
• The investigation found that the flight crew did not practice CRM.
• The crew did not speak English proficiently except for the first officer. 
• When running low on fuel the first officer did not declare an emergency using standard emergency terminology. 
• During the survivable crash event the seats did not protect the passengers or crew adequately.

 

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• All flight crew members will speak English proficiently.
• The airline crew will manage the flight including obtaining current weather information for their destination and alternate airports throughout the flight and actively manage their fuel situation.
• Fuel on board, including fuel reserves will be managed such that adequate fuel remains on board to safely complete the flight as planned.
• The crew will declare minimum fuel to ATC.  If they determine they need immediate landing priority the crew will declare an emergency using the words "MAYDAY, MAYDAY, MAYDAY," or "EMERGENCY" before running out of fuel.
• 9g static seats will adequately protect the passengers and crew in a survivable crash up to the point of fuselage break up.

 

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CRM accidents:

Eastern Airlines, Flight 401, Miami, Florida, December 29, 1972

Eastern Airlines Flight 401 crashed into the Florida Everglades while on approach to Miami International Airport. The National Transportation Safety Board (NTSB) determined that the crash was the result of an inadvertent autopilot disconnection that went unnoticed by the flight crew as they were attempting to correct an unsafe landing gear position indication. The NTSB determined that the uncommanded descent into the Everglades was the result of the flight crew's failure to monitor the airplane's flight path and an improper division of duties on the flight deck while troubleshooting an anomalous system indication. Of the 163 persons on board 112 were killed in the crash. This accident was one of the precipitating accidents leading to the development and industry-wide adoption of flight crew resource management philosophies and training.

NTSB accident report: Eastern Airlines Flight 401

See accident module

United Airlines, Flight 173, Portland, Oregon, December 28, 1978

On December 28, 1978, a McDonnell Douglas DC-8-61 turbofan powered airplane operated by United Airlines and registered as N8082U, crashed into a wooded suburban area while on approach to Portland International Airport, Portland, Oregon.

Upon approach to Portland International Airport, the aircraft experienced a landing gear malfunction indication and could not determine if the landing gear had been safely extended. The flight crew elected to hold at 5,000 feet to troubleshoot the landing gear anomaly and prepare the aircraft for an emergency landing. With one exception, about 38 minutes into the hold, little was said concerning the amount of fuel onboard and what was needed to complete the approach to the airport. Approximately one hour after beginning the hold, and during the approach to the airport, the aircraft ran out of fuel and crashed approximately six miles northeast of the airport.  Of the 189 people onboard the aircraft, ten were killed and 23 were seriously injured.

NTSB accident report: United Airlines Flight 173

See accident module

Accidents with seat failures:

These accidents were studied during development of the16g seat rule (see Resulting Regulations and/or Policy Changes section for more details).  Also see the American Flight 625 lessons learned module in this database.

Event	Airplane	Date	Location	NTSB Accident Report
Allegheny Airlines Flight 121	DC9-31	23-Jun-76	Philadelphia International Airport	Allegheny Flight 121
Mohawk Airlines Flight 405	FH227B	3-Mar-72	Near Albany, New York	Mohawk Flight 405
United Airlines Flight 553	B737-222	8-Dec-72	Near Midway Airport, Chicago	United Flight 553
Ozark Airlines Flight 809	FH227B	23-Jul-73	Near St. Louis, Missouri	Ozark Flight 809
Alaska Airlines Flight 60	B727-81	5-Apr-76	Ketchikan, Alaska	Alaska Flight 60
ALM Dutch Antillean Airlines Flight 980	DC9-33F	2-May-70	St Croix, Virgin Islands (U.S.)	ALM Flight 980
American Airlines Flight 625	B727-95	27-Apr-76	St. Thomas, Virgin Islands (U.S.)	American Flight 625
Capitol Airlines Flight C2C3/26	DC8-63F	27-Nov-70	Anchorage, Alaska	Capitol Flight C2C2/26

The British Midland Flight 92 accident is one that showed some of the weaknesses of 9g seats and the benefits of 16g type seats.  The seats of the accident airplane were basically 16g prototype seats.  See the British Midland Flight 92 lessons learned module in this database for more on the seat performance.

British Midland, Flight 92, Kegworth, United Kingdom, January 8, 1989

Approximately 13 minutes after takeoff from London's Heathrow Airport, on a flight planned to Belfast, Ireland, the outer portion of a fan blade on the number one engine failed as the airplane was climbing through 28,000 feet. The fan blade failure resulted in high levels of airframe vibration, a series of compressor stalls in the left engine, fluctuation of the left engine parameters, and smoke and fumes in the flight deck. The flight crew, believing that the right engine had failed, reduced thrust on that engine, and subsequently shut it down. The airframe vibration ceased as soon as thrust was reduced on the right engine, reinforcing the crew's identification as the right engine having been the engine that had failed.

The crew initiated a diversion to East Midlands Airport, which progressed normally until, at 2.4 nautical miles from the runway, a fire warning and abrupt thrust loss occurred on the left engine. Attempts to restart the right engine were unsuccessful, and the airplane crashed approximately one-half mile short of the airport. Thirty-nine passengers died in the accident, and eight others died later due to their injuries. Of the other 79 occupants, 74 suffered serious injury.

Accident report: British Midland Flight 92

See accident module

 

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This accident was a landmark for the international adoption of English as the standard language of aviation. The FAA worked with ICAO to start an English language initiative and eventual requirement for all flight crews to be proficient in the English language to a minimum ICAO standard. The English language standard is detailed in AC 60-28 which references the ICAO requirement. The FAA regulation that drives the requirement is 14 CFR 91.703.

This accident was also the impetus for the creation of FAA International Safety Audits. The audits are reviews of Civil Aviation Authorities (CAA) capabilities (International equivalent of the FAA for each country) vs. eight key criteria. The DAAC was the first CAA to be audited and was found deficient in several areas which were fixed subsequently.

The FAA ATC incorporated into air route traffic control centers equipment to provide a recorded broadcast of traffic management information that can be monitored by all aircraft within each center's boundaries to provide pilots with early indications of potential delays en route.

FAA ATC management of all air traffic control facilities formally briefed all air traffic controllers on the circumstances of the accident, and emphasized the need to request from flight crews clarification of unclear or ambiguous transmissions that convey a possible emergency situation or need for additional ATC assistance.

This accident highlighted the value of the new 14 CFR 25.562 dynamic seat rule which was released in 1986. The rule required newly designed transports to use seat installations certified to the new 16g dynamic load standard. The accident airplane had only 9g static seat installations certified to the previous 14 CFR 25.561 emergency load conditions.

Avianca Airlines mandated CRM training for all crews.

History of Seat Standards

From 1956 until 1988 Transport category airplane seats were designed to meet the standards contained in 14 CFR 25.785 (seats, berths, safety belts, and harnesses), in14 CFR 25.561 (Emergency landing conditions), and in Technical Standards Order (TSO) C39b (Seats). 14 CFR 25.785(a) requires that each seat (including a crewmember seat as well as a passenger seat), berth, safety belt, harness, and adjacent part of the airplane be designed such that the occupant who experiences the inertial forces specified in 14 CFR 25.561 will not suffer serious injury in an emergency landing. The inertial forces in 14 CFR 25.561(b) are specified as ultimate forces experienced by the occupant and are treated as statically applied loads. The seats produced these standards are known as 9g seats.

Airplane Structure vs. Seat Strength Research

An evaluation of the crash dynamic characteristics of transport category airplanes indicates that the present Part 25 requirements, with a few exceptions, provide adequate protection for the occupants. A review of existing accident data has shown that, for survivable accident scenarios, the airplane structure remains substantially intact and provides a livable volume for the occupants throughout the impact sequence. This finding was confirmed by the results of the FAA/NASA controlled impact demonstration (CID) involving a remotely controlled, fully instrumented transport category airplane.

 

Video - FAA/NASA CID montage:

 

 

Video - FAA/NASA CID test outside:

 

 

 

Fuselage section drop tests

The FAA’s Dynamic Vertical Drop Test Facility, is located at the FAA William J. Hughes Technical Center, in Atlantic City, New Jersey.  It is used to obtain test data needed to set crashworthiness standards.  It has been used to conduct vertical impact tests on a series of transport category airplane fuselage sections of airplanes such as the Boeing 737.  The tests are conducted to determine the impact response characteristics of items including seats/occupants to assess the adequacy of their design standards and regulatory requirements.

Video - fuselage drop test real time:

 

 

Video - fuselage drop test slow motion:

 

 

Longitudinal Impact Testing

Longitudinal impact tests of a fuselage section with several seat rows were conducted at the Transportation Research Center of Ohio.  The goals accomplished were:

• Measured the response of the seats and airframe structure to simulated crash loads.
• Evaluated the 16g forward test method.
• Found that the airplane structure could successfully take the loading from several seats in a dynamic test even though airplane is designed for 9 static loading.

 

 

Studies of Accident Data

From preliminary review of accident data, it was found that incidents of undesirable seat performance were usually related to cabin floor displacement and excessive lateral inertial loads. From those studies, it became evident that the identified seat deficiencies could be eliminated by establishing dynamic test standards providing the same level of impact injury protection and structural performance as that provided by the airplane structure itself. In this regard, dynamic test standards representative of two distinct survivable impact scenarios were developed. These standards, which are defined in the form of cabin floor pulses and respective performance standards, provide a means of demonstrating the occupant impact protection feature of seats and ensure that the level of safety provided by the seats is consistent with that provided by the airplane structure.

16g Dynamic Seat Rule

Rulemaking upgraded the static load factors defined in 14 CFR 25.561 in the upward, downward, and sideward directions, and to add an aft direction requirement.  Rule 14 CFR 25.562 added dynamic test standards for seats. The standards would require the demonstration of both occupant response and seat/restraint system structural performance. They provide a more representative evaluation of the interaction of the occupant, the seat, and the restraint system and yield data for impact injury analyses.

Two Dynamic Test Conditions Added: 16g Forward and 14g Down

Two dynamic test conditions were selected based on impact scenarios developed from analyses of survivable ground impact data. One test condition combines vertical and longitudinal loads to simulate ground impact following a high-rate vertical descent. This test condition emphasizes occupant vertical loading and evaluates the means provided to reduce spinal injury under the loads typically resulting from an impact of this nature.

The second test, with a predominantly longitudinal component, simulates horizontal impact with a ground-level obstruction. This test condition provides an assessment of the occupant restraint system and seat structural performance. The selection of these two dynamic test conditions is consistent with the results of the crash scenario studies. These dynamic test standards are considered appropriate for all transport category airplanes, regardless of size.

Video – Example 16g forward structural test on business class seat. Notice that the seat attachment fixture applies simulated floor deformation to the seat. In this way the seat is proven to stay attached even when the floor under it is deformed during a crash.

 

 

 

Video - Top view of 16g forward structural test on business class seat. Notice that the seat is yawed vs. the direction of travel to account for airplane yaw during the impact sequence.

 

 

Injury Criteria Tests Added

An important part of any test procedure is the pass or fail criteria. The rule established such criteria by defining standards that directly relate selected parameters measured during a dynamic test to injury criteria based on human impact injury limits. The performance criteria are used to evaluate the occupant/seat protection system potential for preventing or minimizing serious injuries from both primary and secondary impacts. Of major concern are secondary head impacts which can inflict debilitating injuries and result in concussion and unconsciousness. The measure of potential head injury proposed in the notice is the Head Injury Criteria (HIC) used in Federal Motor Vehicle Safety Standard No. 208 (49 CFR 571.208). The HIC is applied where the results of the seat dynamic tests show that structure or other items of equipment are within the occupant's head strike envelope. The head acceleration time history is measured during the dynamic test and evaluated with the HIC when secondary impact can occur.

The two videos below feature a comparison of an inflatable lap belt (airbag) equipped seat place vs. one without.  Inflatable lap belts that deploy an airbag to protect passengers from head injury are a relatively new development.

Video – Example Head Injury Criteria (HIC) economy class seat test

 

 

Video – Example HIC economy class seat test top view

 

 

Spinal injuries also occur in airplane crashes. Additional testing with transport category airplane seats with a lap belt restraint system indicated that the pelvic load peaks while the anthropomorphic dummy is still seated in a predominantly upright position. These tests confirm that the spinal load injury criteria can be used in assessing the dynamic performance of transport category airplane seats. Pelvic loads can be used in assessing the probability of spinal injury, and they are straight forward, easily measured, and require no additional analysis or interpretation. A maximum pelvic load of 1500 pounds would assure a low probability of spinal injury.

Video – Example HIC and femur load test on pilot seat:

 

 

Video – Example HIC and femur load test on economy class seat

 

 

In both videos note the heavy knee impact which loads the femurs.

Crash investigations have shown that localized cabin floor deformation can occur in survivable crashes. This has been confirmed by the controlled impact demonstration and drop test involving transport category airplanes. The inability of some seats to accommodate such deformations, remain in place and restrain the occupants can contribute significantly to the degree of injury during a crash. The simulated floor deformation used in the dynamic tests, while not intended to be a measure of floor strength or deformation capability, will demonstrate the tolerance of the seat and its attachments to deformations that could occur in an actual crash.

The static strength requirements of 14 CFR 25.561(b)(3) were increased to provide a level of safety for seats and fixed items of mass consistent with dynamic tests standards and accepted industry practice. It is expected that increased static strength requirements will assure a more uniform level of safety in the cabin floor structure, seat tracks, fittings, fixed items of mass, and in the seats. The increased lateral static strength and the added rearward static strength requirements would also improve the conditions for rapid evacuation during an emergency landing by limiting the obstruction of aisle space.

Section 25.561(d) and a corresponding provision in 14 CFR 25.562 was added to clarify that the rapid evacuation of occupants following impact must not be impeded by structural deformation.

In summary, this amendment increases the capability of the occupant seat and restraint system of transport category airplanes to absorb a crash impact and to provide occupant protection from items of mass that may become loose on impact.

These seat safety standards apply to all transport category airplanes for which an application for type certificate is made on or after the effective date, regardless of whether the airplanes are used in air carrier service as if 1988.  It is also applicable to newly manufactured airplanes as of October 27, 2009.

 

 

Research on crash dynamics continues. Here are figures and video showing an example of state-of-the-art modeling of an entire transport airplane including seats and passengers in a survivable crash event. This model has been validated extensively using test, analysis, and recorded results from a similar crash event. (Provided courtesy of Gerardo Olivares, Ph.D., National Institute for Aviation Research (NIAR), R & D Crashworthiness Group.

Here is a video simulation of a crash event using the model:

 

 

 

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No airworthiness directives were issued as a result of this accident.

 

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Airplane Life Cycle:

• Operational

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Accident Threat Categories:

• Cabin Safety / Hazardous Cargo
• Crew Resource Management
• Fuel Exhaustion

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Groupings:

• Approach and Landing

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Accident Common Themes:

• Human Error
• Flawed Assumptions

 

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Human Error

The flight crew did not communicate their critical fuel situation to ATC as an emergency.  They did not use crew resource management techniques to act on their critical fuel situation to be approved for an emergency landing.

Flawed Assumptions

The design and regulatory requirements for the certification of the Boeing 707 (and other contemporary aircraft) mandated a 9g static seat capability which was shown to be inadequate in this accident. Since this accident, and other similar accidents, a 16g dynamic seat standard has been adopted which has resulted in a significant safety benefit in this type of accident.

 

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Recent Accidents involving Airplanes with 16g seats

There were two recent accidents that demonstrated the effectiveness of the 16g seat rule in protecting passengers and crew.  In each accident, the fuselage broke into three sections, but there was no fire.  These are typical characteristics of what should be a survivable accident.  Each airplane had 16g seats.

AIRES Flight 8250, 737-700 in San Andreas Island, Colombia, August 16, 2010

AIRES Flight 8250 was a domestic scheduled passenger flight which crashed on August 16, 2010, on the Colombian island of San Andres, in the Caribbean. There were 131 people (125 passengers and 6 crew members) aboard. Of the total occupants it was reported that 2 were fatally injured and 4 seriously injured. The aircraft, a Boeing 737-73V, was en-route from the Colombian capital Bogota when it crashed while attempting to land in bad weather, breaking into three pieces on impact.

Turkish Airlines 737-800 in Amsterdam, February 25, 2009

A Boeing 737-800 (Flight TK1951) operated by Turkish Airlines was flying from Istanbul Atatürk Airport in Turkey to Amsterdam Schiphol Airport, on 25 February 2009. As this was a ‘Line Flight Under Supervision', there were three crew members in the cockpit; the captain, who was also acting as instructor, the first officer, who had to gain experience on the route of the flight, and who was accordingly flying under supervision, and a safety pilot who was observing the flight.

There were also four cabin crew members and 128 passengers on board. During the approach to runway 18R at Schiphol Airport, the aircraft crashed into a field at a distance of about 1.5 kilometers from the threshold of the runway. Four crew members, including the three pilots, and five passengers were killed. Three crew members and 117 passengers sustained injuries, 12 of which were serious.

Accident report: Turkish Airlines Flight 1951 accident report

 

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Technical Related Lessons

The post-crash safety provided by 9g static seats was demonstrated to be inadequate during this survivable accident. (Threat Category: Cabin Safety/Hazardous Cargo)

• The investigation determined that this accident was survivable, and that the majority of injuries and fatalities was due to the failure of the seat structures. Had the seats been more structurally capable, and able to absorb the loads imparted by the impact, and associated deformation, the investigation concluded that the number of injuries and fatalities would have been substantially reduced.

Maintaining an environment of open, clear, and accurate communication among crew members, and between flight crews and air traffic controllers is essential for proper decision making, especially in an emergency situation. (Threat Category: Crew Resource Management)

• The flight crew was aware that their fuel state was becoming increasingly critical as the flight progressed and was frequently delayed due to weather induced holds. The captain repeatedly requested that the first officer inform ATC that the situation had become an emergency, but the first officer did not properly convey the urgency of the situation to ATC and did not declare an emergency. As a result, ATC was not aware of the deteriorating situation onboard flight 52. Had an emergency been declared, following the go-around, rather than direct the flight back out to a sequenced approach position, ATC would have provided expedited handling, and given the flight priority for landing, which might have prevented the accident.

Common Theme Related Lessons

The safety provided by passenger accommodations and cabin equipment should be commensurate with the associated threat levels to which they will be exposed. (Common Theme: Flawed Assumptions)

• It was determined by the investigation that though this accident was survivable, the failure of the seats and other cabin accommodations contributed to the high level of injuries and fatalities. The cabin accommodations were required to sustain a 9g static load, which was exceeded during this crash. Post-accident investigations, and information gathered from this, and other accidents, led to the adoption of a 16g dynamic seat standard which has resulted in a substantial reduction in the ratio of injuries and fatalities in similar accidents.

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