By Simon Hradecky, created Wednesday, Dec 21st 2016 01:12Z, last updated Wednesday, Aug 29th 2018 16:11Z An Aerosucre Colombia Boeing 727-200, registration HK-4544 performing a freight flight from Puerto Carreno to Bogota (Colombia) with 6 crew, did not become airborne while taking off from Puerto Carrena's runway 25 at 17:18L (22:18Z), broke through the airport perimeter fences, became airborne, lost height again about 3 minutes later, impacted ground about 5nm from the airport and burst into flames. Two persons were rescued alive, four persons died on scene, one of the initial survivors succumbed to the injuries in hospital. The other survivor is reported in stable condition on Dec 21st 2016.



Colombia's Civil Aviation Authority Aerocivil reported the aircraft crashed three minutes after takeoff from Puerto Carreno. 5 occupants were killed, one occupant survived correcting earlier reports of 4 fatalities and 1 survivor.



On Feb 19th 2017 Colombia's Grupo de Investigacion de Accidentes e Incidentes aereos (GRIAA) released their preliminary report in Spanish reporting that at the time of the departure the aerodrome was not controlled. Two aircraft departed the aerodrome prior to the Boeing 727 using runway 07 for departure.



According to flight data and cockpit voice recorder the crew remained unaware of the last Metar, which for 22:00Z read: "01008KT 9999 FEW020 SCT200 31/32 A///". The crew was backtracking the runway for departure from runway 25, completed their checklists prior to the 180 degrees turn, following the 180 degrees turn the aircraft came to a stop slightly off the runway heading (this was later corrected during the takeoff run). The crew determined their V1=Vr=127 KIAS, V2 was 141 KIAS, the EPR for takeoff was set to 2.12 (left and right engine, JT8D) and 2.11 (tail mounted engine).



According to video evidence available the aircraft impacted the airport perimeter fence (height of 2.5 meters above runway level), a military structure (small tower serving as shelter, height of 3 meters) and a tree (height 7 meters) at the military unit just past the runway end. The impact caused the right hand main gear, the right hand main gear doors and the right hand inboard trailing flaps to separate (the components were distributed in a range of about 410 meters around), a fire started in the #3 (right hand) engine. According to the CVR the crew saw a power loss from the #3 engine as well as the loss of hydraulic fluid following the impact, the crew initiated a fuel dump. The aircraft climbed out reaching a maximum altitude of 790 feet while gradually turning and rolling right reaching 60 degrees of bank angle, loss of speed and lift and impact with the ground about 4nm from the runway end at approximate coordinates N6.1873 W67.5678. A post impact fire erupted. One occupant survived, 5 were killed in the accident.



The captain (58, ATPL, 8,708 hours total, 6,822 hours on type) was assisted by a first officer (39, CPL, 3,285 hours total, 3,285 hours on type).



The GRIAA reported that the load manifest was not found within the wreckage of the aircraft nor was a copy found in the airport office. The investigation assumes that the aircraft departed with 9 pallets weighing a total of 19,820 lbs.



In Aug 2018 the GRIAA released their final report in Spanish concluding the probable causes of the crash were:



- Inadequate flight planning by both operator and crew by failing to perform dispatch procedures such as takeoff performance calculations and verification of limits imposed by the operational conditions of the aerodrome correctly.



- Wrong decision making by the crew by not considering a key aspect affecting the performance of the aircraft, the prevailing tail wind at the time of departure.



- Incorrect selection of takeoff speeds V1, Vr and V2 by the crew, which corresponded to an aircraft without flap modifications, which resulted in the crew initiating rotation 5 knots over required speed, which increased the takeoff roll distance.



- Erroneous rotation technique applied by the pilot flying, that delayed the rotation and further lenghtened the takeoff run.



- Loss of components (landing gear, trailing inboard flap) and damage to functional systems (loss of engine #3 engine, loss of hydraulic system) needed for aircraft control in flight.



- Loss of control in flight by lift asymmetry as well as the hydraulic system losing fluid and subsequently hydraulic power causing the control forces to exceed the capacity of the crew making it impossible to maintain adequate directional control and stability of the aircraft.



Contributing factors were:



- Breach of Aeronautical regulations by the operator by operating the 727-200 into an aerodrome not suitable for the operation of a 727-200, in addition the operator had not been authorized to operate a 727-200 into Puerto Carreno in the Operating Specifications of the company approved by the Aviation Authority.



- Lack of standardization and supervision by the operator which permitted a Boeing 727-200 with flaps modification to operate with a speed reference table corresponding to aircraft without such modification.



- Execution of the takeoff at a weight exceeding the maximum takeoff weight permitted by the conditions at Puerto Carreno Aerodrome as defined in the aircraft performance charts.



- Omission by the crew to activate the standby hydraulic system which might have provided emergency hydraulic pressure permitting to regain control in flight.



- Lack of supervision by the Civil Aviation Authority which permitted the operator to operate Boeing 727-200 into Puerto Carreno for several years and permitted the operation of the 727-200 into Pueto Carreno although the aerodrome was not suitable and was not authorized for the aircraft type.



The GRIAA analysed the takeoff weight, according to estimations, most likely was 166,000 lbs. The maximum takeoff weight for an unmodified flaps system at 25 degrees takeoff flaps would have been 157,000 lbs (which was the performance tables used by the crew), for a modified flaps system at 30 degrees takeoff flaps the maximum permitted takeoff weight would have been 164,000 lbs. The crew had selected V1/Vr=127 KIAS and V2=141 KIAS, which corresponded to an unmodified flaps 25 takeoff. Using the AOM for the modified flaps system permitting 30 degrees flaps for takeoff the reference speeds would have been: V1/Vr=120 KIAS, V2=134 KIAS.



The GRIAA analysed that the aircraft departed with a tail wind component of 4 knots. The crew decided to taxi to runway 25 although not based on the official weather report. It is probable that crew observed the windsock during taxi. The GRIAA therefore analysed that the crew was aware of the tail wind while departing from runway 25. At the time of the accident the tower of Puerto Carreno was closed and the aerodrome was uncontrolled, hence no assistance was provided by a controller. The analysis permits to conclude that the meteorological conditions had a direct relation to the sequence of events leading to impact of the aircraft with obstacles during initial climb.



The GRIAA reported the aircraft reached a pitch angle of 7 degrees nose up about 7 seconds after initiating the rotation. This resulted in the aircraft travelling 262 meters/859 feet during rotation, while at a normal takeoff rotation of 2-3 degrees nose up per second the distance travelled would have been 128 meters/419 feet.



The runway of Puerto Carreno did not permit operation of a Boeing 727-200 by its pavement strength and runway dimensions.



The investigation concluded that maintenance was not a factor into the accident.



The investigation analysed that the takeoff distance available would have been sufficient for a takeoff at the correct flaps 30 performance data (takeoff distance required), the aircraft was within weight and balance limits, the corrected speeds for a 30 degrees takeoff would have been lower than those selected by the crew, which contributed to the prolonged takeoff run. The rotation for takeoff at the correct speed would have been initiated 411 meters ahead of the runway end while in the actual flight the rotation was initiated 308 meters before the runway end. With the slow takeoff rotation of 1 degree/s additional 134 meters were needed to become airborne. The tail wind component added 146 meters to the takeoff distance required.



The loss of the right inboard flaps produced an asymmetric lift but did not damage other systems. The loss of the landing gear however damaged hydraulic lines causing a leak and causing the complete gradual depressurization of the hydraulic system A, which gradually lost the ability to operate ailerons, elevators, slats, flaps, the lower section of the rudder and increased the aerodynamic drag. Although not heard by any crew discussion it is probable that the hydraulic system B was equally affected losing the brakes. As result of the depletion of hydraulic fluid over time the FDR shows the lower section of the rudder initially follwed the pilot inputs but its deflection lowered as hydraulic pressure reduced until the rudder remained in a neutral position disabling the crew to counteract asymmetric thrust and lift despite full rudder pedal deflection. In addition, although the control wheel was deflected fully to the left, the ailerons were not able to counter the right roll tendency.



According to the FDR and measurements the hydraulic system lost about 4.01 gallons of fluid per minute and depleted within 103 seconds. The CVR revealed that the crew did not attempt to activate the standby hydraulic system which might have enabled them to regain control of the aircraft.



The #2 engine (tail mounted) lost about 800 lbs of thrust, which however did not affect the aircraft's ability to continue flight, just prior to the collision with the airport perimeter fence (Editorial note: On Aug 29th 2018 a native Spanish speaker made us aware of a minor misunderstanding of the report, we had originally understood the loss of thrust on the tail mounted engine had occurred because of the collision with the fence). At the time of impact with the fence the aircraft had reached 134 KIAS. Upon impact with a tree and a hut the #3 engine (right hand) lost power which could not be recovered throughout the remainder of the flight.



Metars:

SKPC 202300Z 01008KT 9999 FEW020 SCT200 30722 A////

SKPC 202200Z 01008KT 9999 FEW020 SCT200 31/22 A////

SKPC 202100Z 01012KT 9999 FEW023 32/21 A////

SKPC 202000Z 07008KT 9999 FEW023 32/22 A2963



Video of runway overrun (Video: Aviación Comercial en Colombia):

https://www.youtube.com/watch?v=2DxOZI-oFCg



Another video of the overrun (Video: Las2orillas):

https://www.youtube.com/watch?v=381RJkT52tw



Video of aircraft airborne (Video: Sebastian Salazar H):

https://www.youtube.com/watch?v=6r_Vokp-InE



The aircraft seen airborne, right inboard flap missing (Photo: Guillermo Tovar):





Impressions from the crash site (Photos: Aviación Comercial en Colombia):













Aerial view of crash site (Photo: GRIAA):





Map of Wreckage distribution (Graphics: GRIAA):





Flight trajectory (Graphics: GRIAA):





Map (Graphics: Google Earth):









