Last revised: September 06, 2013
ATC - 25 Best Years -
Album # 9.
(Midair Collision) -Tenerife, Canary Islands
|THE 2nd WORST AVIATION DISASTER IN HISTORY!|
(Artists Depiction of this
March 27, 1977 - Tenerife, Canary Islands - collision of two B-747s. Pan Am flight #1736 and KLM flight #4805. 583 people lost their lives when KLM B-747 started his takeoff roll without clearance and collided with a Pan Am B-747.
Both B-747's had been diverted to Tenerife, as well as many other aircraft, from Gran Canaria Airport after a bomb exploded there, and the threat of another bomb closed the airport while a search was conducted. Air Traffic Controllers were forced to park many of the jets on a taxiway, thereby blocking it. Additionally a dense fog developed at Tenerife, greatly reducing visibility.
When Gran Canaria Airport reopened, the parked jets blocking the taxiway at Tenerife required both B-747's to taxi to the only runway in order to get in position for takeoff. Due to the fog, neither aircraft could see the other, nor could the controller in the tower see the runway or the two B-747's on it.
Since the airport did not have ground radar, the controller could only identify the location of each jet by radio voice reports. As a result of several misunderstandings in the communications, the KLM flight attempted to take off while the Pan Am flight was still on the runway. The resulting collision destroyed both jets. (583 Fatalities)
Immediately after lining up, the KLM captain, the most senior
pilot working for KLM, advanced the throttles (a standard procedure
known as "spool-up", to verify that the engines are operating properly for
takeoff) and the co-pilot, surprised by the maneuver, quickly advised the
captain that ATC clearance had not yet been given.
The Copilot read the flight clearance back to the controller, completing the read-back with the statement: "We are now at takeoff." The Captain interrupted the co-pilot's read-back with the comment, "We're going."
The controller, who could not see the runway due to the fog, initially responded with "OK" (terminology which is nonstandard), which reinforced the KLM captain's misinterpretation that they had takeoff clearance. The controller's response of "OK" to the co-pilot's nonstandard statement that they were "now at takeoff" was likely due to his misinterpretation that they were in takeoff position and ready to begin the roll when takeoff clearance was received, but not in the process of taking off. The controller then immediately added "stand by for takeoff, I will call you," indicating that he had not intended the clearance to be interpreted as a takeoff clearance.
A simultaneous radio call from the Pan Am crew caused mutual interference on the radio frequency, which was audible in the KLM cockpit as a three second long whistling sound. This made the crucial latter portion of the tower's response audible only with difficulty by the KLM crew.
The Pan Am crew's transmission, which was also critical, was reporting, "We're still taxiing down the runway, the Clipper 1736!" This message was also blocked by the heterodyne and inaudible to the KLM crew. Either message, if heard in the KLM cockpit, would have given the KLM crew time to abort the takeoff attempt.
Due to the fog, neither crew was able to see the other plane on the runway ahead of them. In addition, neither of the aircraft could be seen from the control tower, and the airport was not equipped with ground radar.
After the KLM plane had started its takeoff roll, the tower instructed the Pan Am crew to "report when runway clear." The Pan Am crew replied: "OK, we'll report when we're clear." On hearing this, the KLM flight engineer expressed his concern about the Pan Am not being clear of the runway by asking the pilots in his own cockpit, "Is he not clear, that Pan American?" The Captain emphatically replied "Oh, yes" and continued with the takeoff.
According to the Cockpit Voice Recorder (CVR), the Pan Am Captain said, "There he is." when he spotted the KLM's landing lights through the fog just as his plane approached exit C-4. When it became clear that the KLM was coming towards them at takeoff speed, the Captain exclaimed, "Goddamn, that son-of-a-bitch is coming straight at us!" while the Copilot yelled, "Get off! Get off! Get off!".
The Pan Am crew applied full power to the throttles and took a sharp left turn towards the grass in an attempt to avoid a collision. By the time the KLM Captain noticed the Pan Am on the runway ahead, his aircraft was already traveling too fast to stop. In desperation he prematurely rotated his aircraft and attempted to clear the Pan Am by climbing away, causing a tail-strike for 66'.
The KLM was within 100m of the Pan Am when it left the ground. As it did so, its excessively steep angle of attack allowed the nose gear to clear the Pan Am but the engines, lower fuselage and aft landing gears struck the upper right side of the Pan Am's fuselage at approximately 140 knots ripping apart the center of the Pan Am jet almost directly above the wing. The right side engines crashed through the Pan Am's upper deck immediately behind the cockpit.
The KLM plane remained briefly airborne following the collision, but the impact with the Pan Am had sheared off the #1 (outer left) engine, and the #2 (inner left) engine had ingested significant amounts of shredded materials from the Pan Am.
The KLM pilot quickly lost control, and the B-747 went into a stall, rolled sharply, and hit the ground at a point 500' past the collision, sliding a further 300m down the runway. The full load of fuel which had caused the earlier delay ignited immediately.
The Pan Am captain said that sitting in the nose of the plane probably saved his life. "We all settled back, and the next thing an explosion took place and the whole left side of the plane was torn wide open." The other 56 passengers and 5 crew members (including the pilots and flight engineer) on the Pan Am B-747 survived by walking out onto the left wing, the side away from the collision, through holes in the fuselage.
About 70 crash investigators from Spain, the Netherlands, the USA, and KLM and Pan Am concluded that the fundamental cause of the accident was that the KLM Captain took off without takeoff clearance. The reason for his mistake may have been a desire to leave as soon as possible in order to comply with KLM's duty-time regulations, and before the weather deteriorated further.
Other major factors were the sudden fog greatly limiting visibility (the control tower and both crews were unable to see each other). Simultaneous radio transmissions resulting in neither message being heard. The crowded airport placing additional pressure on all parties: KLM, Pan Am and Air Traffic Control. An ambiguous transmission from the tower to KLM. If the Pan Am jet had not taxied beyond the third exit, the collision would not have occurred.
Other contributing factors: KLM's captains failure to confirm tower instructions. this flight was one of his first after spending 6 months training new pilots on a flight simulator, where had been in charge of everything (including simulated ATC), hence having been away from the real world of flying for an extended period. The flight engineer's apparent hesitation to challenge the captain further, possibly because the Captain was not only senior in rank, but also one of the most able and experienced pilots working for KLM. (Both the Captain and the Copilot dismissed the flight engineer's question).
extra fuel on the KLM B-747 delayed takeoff an extra 35 minutes,
which gave time for the fog to settle in.
extra fuel added forty tons of weight to the jet, which made it more
difficult to clear the Pan Am when taking off.
extra fuel increased the size of the fire that ultimately killed everyone
accident had a major influence on the aviation industry, particularly in
the area of communications. An increased emphasis was placed on using
standardized phraseology in ATC communications by both controllers and
pilots alike, thereby reducing the chance of misunderstandings. As part of
these changes, the word 'takeoff' was removed from general usage and is
spoken only by ATC when actually clearing an aircraft to take off.
Less experienced flight crew members were encouraged to challenge their captains when they believed something was not correct, and captains were instructed to listen to their crew and evaluate all decisions in light of crew concerns. This concept was expanded into what is known as Crew Resource Management (CRM).
CRM is a procedure and training system where human error can have devastating effects and is used primarily for improving air safety. CRM focuses on interpersonal communication, leadership, and decision making in the cockpit.
CRM training is now mandatory for all airline pilots. The training
covers a wide range of knowledge, skills and attitudes including
communications, situational awareness, problem solving, decision making,
and teamwork. CRM is a management system which makes optimum use of all
available resources: equipment, procedures and people to promote safety
and enhance the efficiency of operations.
April 4, 1977 - Hope, GA - A Southern Airways DC-9 entered a severe hailstorm, both engines failed and the crew executed a forced emergency landing on a two-lane highway.
The DC-9 crew was advised of the presence of embedded thunderstorms and possible tornadoes along the flight route, but they were not subsequently told that the cells had since formed a squall line. As the DC-9 descended from 17,000' to 14,000' it entered a thunderstorm cell with massive amount of water and hail. The hail was intense enough to break the jet's windshield, and due to the ingestion of both water and hail, both engines were damaged and underwent flameout.
The crew were unable to restart the engines and gliding down unpowered, trying to find an emergency landing field within range. As the jet ran out of altitude and options, gliding with a broken windshield and no power the crew made visual contact with the ground and found a straight section of rural highway. They executed an unpowered forced landing, but during the rollout, the DC-9 collided with a gas station/grocery store and other structures.
The NTSB determined the probable cause of the crash was the total and unique loss of thrust from both engines while the jet was penetrating an area of severe thunderstorms. Also the failure of Southern Airways dispatch to provide the crew with up-to-date severe weather information, and the FAA's air traffic control system which did not provide timely dissemination of real time hazardous weather information to the flight crew.
A dissenting opinion: The probable cause was the captain's decision to penetrate rather than avoid an area of severe weather, the failure to obtain all the available weather information despite having knowledge of the severity of the storm system, and the reliance of airborne weather radar for penetration rather than avoidance of the storm.
63 people on the aircraft (including the flight crew) and 9 people on
the ground died; 20 passengers and two flight attendants survived.
FAA initiated a research and development program that required en
route and terminal radars be evaluated to ascertain their capabilities to
detect and display weather. Additionally, the FAA implemented a
standard scale of thunderstorm intensity, based on the National Weather
Service six-level scale, and for ATC to use a common language to describe
The FAA also began providing enhanced dissemination of SIGMETs and Severe Thunderstorm Watch Bulletins and Tornado Watch Bulletins. En route and tower controllers will make broadcasts on receipt of all SIGMETs.
Additionally, the FAA plans to display emergency airports with approved
approaches on radar screens. These airports, not required for normal
operations, will be displayed on a separate filter key in emergency
1977 - President Jimmy Carter selected an expert in aviation law, Langhorne M. Bond, as the 7th FAA Administrator.
March 1, 1978 - Los Angeles, CA - Continental Airlines DC-10, while attempting takeoff from Los Angeles had two tires fail and the crew was forced to abort the takeoff. The jet departed the right side of the runway, the landing gear collapsed, and the jet slid over 600 feet from the runway before stopping. (2 Fatalities)
The NTSB determined the probable cause of this accident was the sequential failure of two tires on the left main landing gear and the resultant failure of another tire on the same landing gear at a critical time during the takeoff roll. Also the partial loss of aircraft braking because of the failed tires and the reduced braking friction achievable on the wet runway surface.
The failure of the left main landing gear and the consequent rupture of
the left wing fuel tanks resulted in an intense fire which added to the
severity of the accident.
FAA issued a new Technical Order to specify performance standards
and qualification test requirements for aircraft tires, and that tires are
compatible with the airframe. The FAA also revised the accelerate-stop
criteria required for wet runway conditions.
Additionally the FAA
requires that pilot training programs include information regarding
optimum rejected takeoff procedures at maximum weights, on wet and dry
runways, and at speeds at or near V1, and for rejected takeoffs which must
be initiated as a result of engine or tire failures.
March 13, 1978 - A United B-727 was hijacked by a lone American immediately after takeoff from San Francisco. The aircraft landed across the Bay in Oakland and the release of cabin crew and passengers was negotiated by the flight crew. The fueling was cut short by the hijacker and the jet took off only partially refueled.
They landed at Denver airport to take on more fuel for Cuba. While
waiting for the fuel, the cockpit crew jumped from the cockpit to escape
the hijacker who then surrendered to the FBI within minutes of the crews
escape. No fatalities, but the 3 cockpit crew members suffered fractures
and torn cartilage from the unassisted 2-story jump.
May 8, 1978 - Pensacola, FL - National Airlines B-727 crashed into Pensacola Bay, 3 miles short of the runway while executing a non-precision approach to land at Pensacola at night in low visibility from fog. Pilot error in failing to maintain minimum descent altitude until the runway was in sight.
The ILS for runway 16 had been out of service since January for runway reconstruction. However, a non-precision approach to runway 25 was available instead. While established on the approach, the first officer neglected to make altitude and approach fix call outs. The ground proximity alarm sounded and the first officer checked his altimeter. He read it as 1,500' and turned off the alarm. The flight data recorder showed the actual altitude was only 500'. The flight crew may have been distracted by the alarm and failed to realize they passed through the minimum descent altitude.
Shortly after they impacted Escambia Bay, barge traffic in the area assisted in the evacuation. 3 passengers drowned attempting to exit the B-727. (3 Fatalities)
Probable Causes: The flight crew had information that a VASI light system for runway 25 was available and operational, but the crew was unaware of this alternate approach aid. Also contributing to the crash was an error of the radar controller. The controller misjudged the jet's distance and turned it to final inside the recommended distance, resulting in the jet being on final approach vector for about 4.5 nmi, close to half the distance of a normal approach. The NTSB concludes the controller "created a situation that would make it impossible for the captain to configure his jet in the manner specified in the flight manual."
reluctance to declare a missed approach pervaded the descent. Radar
controller, captain, first officer and flight engineer all had indications
of an "out of the ordinary" approach, producing a rushed and busy
environment. The captain failed to lower the landing gear immediately
after lowering the flaps to 25 degrees, because he "wanted to avoid
placing a simultaneous demand on the hydraulic system while the flaps were
in transit." Also the first officer never made the required 1,000'
callout. The lack of crew communication and a "no problem here" attitude
resulted in false awareness of altitude and descent rate on the part of
- May 25, 1978 - PATCO began
intermittent slowdowns to protest the refusal of some U.S. carriers to
provide controllers with overseas familiarization "FAM" flights.
- June 21, 1978 - PATCO agreed
to obey a Federal-court injunction and end a "work to rule" slowdown by
its members that had intermittently snarled air traffic during the Spring.
PATCO also agreed to pay a fine of $100,000 to the Air Transport
Association for violating the permanent injunction won by the
ATA in 1970 against air traffic slowdowns.
August 4, 1978 - The Department of Transportation Appropriation Act discontinued funding for the Air Traffic Controllers Second Career Program (A special rehabilitation program). A study revealed that about 50% of the 2,580 controllers eligible to participate in the program either declined or withdrew from training, and only 7% actually entered new careers.
The cost for each successful participant had averaged $370,000. The
House Appropriations Committee report suggested that controllers who had
been incapacitated on the job should seek rehabilitation services under
(Midair Collision) -San Diego, CA
September 25, 1978 - San Diego, CA midair collision between a PSA B-727 and a Cessna-172. All 135 aboard the B-727 and 2 on the Cessna as well as 7 people on the ground were killed, including two children, as both aircraft crashed into North Park, a San Diego neighborhood. Nine others on the ground were injured and 22 homes were destroyed or damaged. (144 Fatalities)
The weather was clear with 10 miles visibility, and the PSA crew was alerted by the approach controller about a small Cessna aircraft nearby. The Cessna-172 was being flown by two licensed pilots. One with a single-engine, multi-engine and instrument flight ratings, as well as a commercial certificate and an instrument flight instructor certificate.
The other pilot, a U.S. Marine Corps sergeant had single and multi-engine ratings and a commercial certificate, and at the time of the accident practicing ILS approaches under the instruction of the 1st pilot in pursuit of his instrument rating. The 2nd pilot was wearing a "hood" to limit his field of vision straight ahead to the cockpit panel in normal IFR training.
The B-727 crashed after a midair collision with a Cessna-172 while on a downwind leg at San Diego. The PSA's flight crew was cited at fault for failing to maintain visual separation with the Cessna after reporting it in sight.
The Cessna was directly in front of and below the B-727 which was descending and rapidly closing in on the small pane, which had taken a right turn to the east, deviating from the assigned course. The B-727 crew never explicitly alerted the tower that they had lost sight of the Cessna. Moreover, if the Cessna had maintained the heading of 70 degrees assigned by ATC instead of turning to 90 degrees, they would have missed each other by about 1000'. The aircraft collided at 2,600'.
The PSA B-727 struck the ground 3 miles northeast of Lindbergh field. It impacted in a high-speed, nose-down attitude while banked 50 degrees to the right. The largest piece of the Cessna impacted about 2 blocks away.
Probable Cause: The failure of the PSA flight crew to follow proper
ATC procedures to "keep visual separation from the Cessna traffic", and did
not alert ATC that they had lost sight of it. Errors on the part of ATC
were also named including the use of visual separation procedures when
radar clearances were available. Also the Cessna did not maintain their
assigned heading after completing a practice instrument approach, nor did
they notify ATC of their course change.
FAA implemented a Terminal Radar Service Area at Lindbergh Airport, San
Diego, CA. They also updated procedures at all airports which are used
regularly by both air carrier and general aviation aircraft.
Additionally, a review of policies regarding the use of visual separation
in terminal areas will be completed as soon as possible.
October, 1978 - Conflict Alert Systems became operational at 51 ARTS III terminals in the contiguous 48 states. Conflict Alert is an automated warning system to assist Air Traffic Controllers in preventing collisions between aircraft.
October 24, 1978 - The Civil Aeronautics Board passed a new law - the Airline Deregulation Act - which permitted the commuter airline industry and air taxis to employ bigger aircraft and made them eligible for the FAA equipment loan-guarantee program. It also created a highly competitive airline industry.
The act also allowed for immediate fare reductions of up to 70% without CAB approval, and the automatic entry of new airlines into routes not protected by other carriers. 22 airline reps submitted applications for dormant airline routes and the CAB awarded 248 new routes to smaller communities which were guaranteed essential air services for 10 years with a government subsidy if necessary. The act also provided equipment loan guarantees to commuter airlines.
When airline deregulation became law, the air traffic control system
required enhancement to keep pace with the increased volumes of traffic
resulting from the new deregulated environment.
December 1, 1978 -
FAA issued a comprehensive set of new
commuter airline regulations governing air taxi and commuter airline
operations, by revising FAR Part 135 to upgrade onboard
safety devices, training and maintenance procedures. The new rules also
required pilots of all multi-engine commuter airlines to hold an Airline
Transport Pilot's (ATP) rating.
December 28, 1978 - Portland, OR - A United Airlines DC-8 with 181 passengers and a crew of 8, from JFK to PDX, in a holding pattern due to a landing gear problem, ran out of fuel and crashed into a wooded populated area of suburban Portland, while attempting to return to the airport. The aircraft delayed at a low altitude for about 1 hour while the flight crew coped with a landing gear malfunction.
NTSB determined that the probable cause was the failure of the captain to monitor properly the aircraft's fuel state and to respond to the low fuel problem. He also didn't respond to the other crewmember's advisories regarding the fuel gauges resulting in fuel exhaustion to all 4 engines.
Contributing to the accident was the failure of the other two flight crew members, either to fully comprehend the criticality of the fuel state or to successfully communicate their concern to the captain who was inattentive because of the landing gear malfunction and preparations for a possible landing emergency.
A total of 189 occupants were on the jet, and 10 lost
their lives (8 passengers, the flight engineer, and a flight attendant).
Serious injuries included 21 passengers and 2 crewmembers.
FAA issued an Operations Alert Bulletin to have FAA
inspectors assure that crew training stresses differences in fuel-quantity
measuring instruments and that all flight crews are made aware of the
possibility of misinterpretation of gauge readings.
FAA directed air carrier operators to ensure that their flight crews
are indoctrinated in the principles of flight deck resource management,
with particular emphasis on the merits of participative management for
Captains and assertiveness training for other cockpit crewmembers.
Last revised: September 06, 2013
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