Crash of a Douglas DC-8-31 in Atlantic City

Date & Time: Apr 28, 1968 at 0523 LT
Type of aircraft:
Operator:
Registration:
N1802
Flight Type:
Survivors:
Yes
Schedule:
Atlantic City - Atlantic City
MSN:
45277/94
YOM:
1960
Crew on board:
4
Crew fatalities:
Pax on board:
0
Pax fatalities:
Other fatalities:
Total fatalities:
0
Captain / Total flying hours:
13849
Captain / Total hours on type:
1756.00
Circumstances:
The crew was completing a local night training flight at Atlantic City Airport. On final approach, the pilot-in-command attempted a go-around when then aircraft lost height and crashed in flames short of runway threshold. All four crew members were seriously injured and the airplane was destroyed. At the time of the accident, both left engines n°1 & 2 were at full power while both right engines n°3 & 4 were at idle power.
Probable cause:
It is believed the aircraft stalled on short final while the crew elected to make a go-around at an insufficient speed, which caused the aircraft to stall and to crash.

Crash of a Douglas DC-8-54F in Ottawa: 3 killed

Date & Time: May 19, 1967 at 1837 LT
Type of aircraft:
Operator:
Registration:
CF-TJM
Flight Type:
Survivors:
No
Schedule:
Montreal - Ottawa
MSN:
45653/178
YOM:
1963
Country:
Crew on board:
3
Crew fatalities:
Pax on board:
0
Pax fatalities:
Other fatalities:
Total fatalities:
3
Captain / Total flying hours:
19400
Captain / Total hours on type:
3700.00
Copilot / Total flying hours:
20748
Copilot / Total hours on type:
8
Aircraft flight hours:
9670
Circumstances:
The aircraft was on a conversion training flight from Montreal to Ottawa with three pilots on board. The aircraft departed Montreal at 1802 hours Eastern Standard Time on an instrument flight plan which was cancelled on reaching the Ottawa area. A hydraulic failure simulation was then carried out following which a touch-and-go landing on runway 32 was accomplished at 1825 hours. According to the recorded data the touch-and-go was accomplished with the ailerons in the manual mode, the flaps were raised to the 250 position during the landing roll and the ailerons were restored to the power mode during the turn following take-off while on a heading of about 260°. After about two minutes of flight on the downwind leg, No. 4 engine was retarded to flight idle and was kept at that setting for about two and a quarter minutes. During this period an average of about 30 left wing down bank was maintained, except at a point about halfway through that period the aircraft banked slowly 180 to the left, followed by a sharp reversal to 100 bank to the right. The length of the downwind leg was consistent with a planned two-engine asymmetric landing. Power was restored to No. 4 engine just before a left turn on to the base leg was started. During that turn No. 4 engine was again retarded to flight idle,then restored to normal power. No. 1 engine was then retarded to flight idle for about 20 seconds, then restored to normal power. The flaps remained at the 250 setting. While turning on to final approach, the pilot-in-command advised the tower that he was as yet undecided whether a landing would be carried out. When the aircraft had passed the UP beacon, about 84 miles from the runway threshold and approximately 200 sec from impact, rudder power was selected to the manual mode and power was reduced on all four engines. No. 4 engine was then retarded to the flight idle position and the other three engines advanced to approach power. About 171 sec before impact, the pilot-in-command advised the control tower that the aircraft would be making a full stop landing. The landing gear was extended 155 sec before impact and 120 sec before impact No. 3 engine was retarded to flight idle: at the same time power was increased on Nos. 1 and 2 engines. At that time the aircraft was at a height of 1 150 ft above the ground and its indicated airspeed was fairly steady around 165 kt. From 109 to 92 sec before impact, the aircraft turned to the right through 340 on to a heading of 3370. Power was reduced, bank applied and the aircraft returned to approximately the runway heading. The flaps were extended to 350, 69 sec before impact. At 54 sec before impact, the rudder was restored to the power mode for less than 6 sec and then returned to the manual mode. Through the period from 69 to 25 sec the rate of descent was relatively constant at about 700 ft/min with the aircraft tending to undershoot, and the airspeed decreasing from 163 to 152 kt. Power on Nos. 1 and 2 engines was progressively increased from 25 sec before impact until near maximum power was reached 8 sec before impact, following which they were retarded to flight idle. A yaw to the right had started 19 sec before impact and 12 sec before impact the throttles were advanced on engines 3 and 4 and they began to spool up. At 9 sec before impact and when some 200 ft above the ground, the left wing down condition could no longer be maintained and the aircraft entered a roll to the right. The roll rate to the right increased rapidly as did the yaw rate. The roll continued until the aircraft struck the ground in an inverted nose low attitude, 1 995 ft short of the threshold of runway 32 and 575 ft NE of its extended centre line. The accident occurred at 1837 hours. The aircraft was destroyed and all three crew members were killed.
Probable cause:
Failure to abandon a training manoeuvre under conditions which precluded the availability of adequate flight control. The following findings were reported:
- The decision to attempt an asymmetric approach with the rudder in the manual mode was improper,
- The information available to the crew in the Air Canada DC-8 Manual, concerning two engine operating procedures, was inadequate,
- The aircraft was tending to undershoot the runway,
- Control was lost when power to the left engines was increased late in the approach, at an airspeed too low for effective rudder control,
- The faulty check valve closed during the flight at least 54 seconds prior to impact.
Final Report:

Crash of a Douglas DC-8-51 in New Orleans: 19 killed

Date & Time: Mar 30, 1967 at 0050 LT
Type of aircraft:
Operator:
Registration:
N802E
Flight Type:
Survivors:
No
Site:
Schedule:
New Orleans - New Orleans
MSN:
45409/19
YOM:
1959
Flight number:
DL9877
Crew on board:
6
Crew fatalities:
Pax on board:
0
Pax fatalities:
Other fatalities:
Total fatalities:
19
Captain / Total flying hours:
19008
Captain / Total hours on type:
475.00
Copilot / Total flying hours:
16929
Copilot / Total hours on type:
15
Aircraft flight hours:
23391
Circumstances:
Delta Air Lines DC-8-51 N802E was scheduled as Flight 9877, to provide crew training for a captain-trainee and a flight engineer-trainee. In addition the flight engineer-instructor was being given a routine proficiency check. At 23:14 a weather briefing was given to the instructor pilot, indicating, "... the only significant weather was a restriction in visibility which was expected to reduce to about two miles in fog and smoke near 0600...". The flight departed the ramp at 00:40 with the captain-trainee in the left seat and the check captain in the right seat. At 00:43 the crew advised the tower they were ready for takeoff and would "...like to circle and land on one (runway 1)." The tower controller then cleared them as requested. The aircraft was observed to make what appeared to be a normal takeoff and departure. At 00:47 the crew reported on base leg for runway 01, and the controller cleared the flight to land. A subsequent discussion revealed that they would execute a simulated two-engine out approach, execute a full stop landing and then takeoff on runway 19. The tower controller observed Flight 9877 in a shallow left turn on what appeared to be a normal final approach. The degree of bank increased to approximately 60° or greater when the aircraft hit the power lines approximately 2,300 feet short and 1,100 feet west of the runway threshold. The DC-8 crashed into a residential area, destroying several homes and the Hilton complex. All six crew members were killed as well as 13 people on the ground, clients and employees at Hilton Hotel. 18 other people were injured, some of them seriously. The aircraft was totally destroyed by impact forces and a post crash fire.
Probable cause:
Improper supervision by the instructor, and the improper use of flight and power controls by both instructor and the Captain-trainee during a simulated two-engine out landing approach, which resulted in a loss of control.
Final Report:

Crash of a Douglas DC-8-33 in Monrovia: 56 killed

Date & Time: Mar 5, 1967 at 0256 LT
Type of aircraft:
Operator:
Registration:
PP-PEA
Survivors:
Yes
Schedule:
Beirut – Rome – Monrovia – Rio de Janeiro
MSN:
45253/5
YOM:
1959
Flight number:
RG837
Country:
Region:
Crew on board:
19
Crew fatalities:
Pax on board:
71
Pax fatalities:
Other fatalities:
Total fatalities:
56
Captain / Total flying hours:
17718
Captain / Total hours on type:
1787.00
Copilot / Total flying hours:
15911
Copilot / Total hours on type:
408
Aircraft flight hours:
16775
Circumstances:
VARIG Flight RG837 departed Rome-Fiumicino Airport, Italy, at 21:08 hours GMT on a flight to Monrovia, Liberia. The flight was uneventful until the crew reported at FL45, five miles from the Roberts VOR. ATC then cleared the flight to descend further down to 3000 feet on the VOR and reported a QNH of 1009 mb. The QNH was read back correctly, but the crew did not mention the descent clearance. The pilot-in-command continued to the VOR at FL45 (4500 feet). After sighting the aerodrome runway lights from vertically overhead, the pilot informed the co-pilot that despite the fact that he had the runway completely in sight he would make an IFR/VOR procedure. A VOR/Locator instrument let-down was commenced from 4500 feet over the VOR at an indicated airspeed of 210 slowing to 170 kt, descending at a rate of between 500 to 700 feet per minute until the aircraft arrived at a point inbound over the coastline at 1800 feet on a heading of 047- degrees with the gear down and 35-deg flaps for landing on runway 04. At this point the co-pilot reported: "Runway in sight a little to the left". During the approach from the coast to the airport, the pilot did not make any use of the DME. After the procedure turn, the aircraft was on the correct VOR radial and a smooth approach was carried out during which the aircraft was flown manually. After the procedure turn, the co-pilot called each 100 feet of altitude and the speed and he checked the indication of the vertical speed indicators. At an altitude of about 1000 feet, flaps were put in the full down position and shortly thereafter, at an altitude of 700-800 feet, the aircraft entered some stratus and, further down, fog patches. When entering the stratus layer, the captain told the co-pilot that it was no longer necessary to report altitude and speed and was instructed to look outside and to report as soon as he could see the runway. Over the FR locator beacon, the altitude was about 800 feet, whereas his correct altitude should have been 520 feet. He then increased his rate of descent to between 1200-1500 ft/min, by reduction of power and by pitching the nose of the aircraft down. About 15 seconds after passing FR the co-pilot reported runway in sight, saying also that the visibility was poor and that they were too low. Descent was continued until the DC-8 impacted the ground 6023 feet from the threshold of runway 04, 180 feet to the right of the runway extended centre line with the aircraft coming to rest after a ground slide of approximately 850 feet. The aircraft caught fire and was totally destroyed. A crew members, 50 passengers and five people on a house were killed.
Probable cause:
The failure of the pilot-in-command to arrest in time the fast descent at a low altitude upon which he had erroneously decided, instead of executing a missed approach when he found himself too high over the locator beacon. The following findings were reported:
- The captain did not make use of the available navigational aids by disregarding the indications of his distance measuring equipment during final approach,
- At an altitude below 1 000 ft, the aircraft entered a stratus layer, which at that time completely obscured the runway,
- At the FR, positioned 1.7 NM before the runway threshold, the pilot-in-command saw that his altitude was 800 ft, whereas the correct altitude should have been 520 ft. Contrary to company instructions, he increased his rate of descent to between 1 200-1 500 ft/min by reducing engine power and pitching the nose of the aircraft down, with the intention to arrest his descent at about 500 ft,
- The attempt to level off was insufficient and/or too late, with the result that the aircraft touched the ground some 6 000 ft before the runway threshold when his glide path angle must have been 4.50 or more,
- During impact and the subsequent ground slide of about 850 it, the aircraft broke,up and caught fire,
- Those crew members who escaped relatively unhurt, once outside, might have directed more effort in further evacuation,
- The fire crew acted promptly, but its limited force and the necessary elapse time to reach the scene of the accident prevented them from saving people who might not yet have died.
Final Report:

Crash of a Douglas DC-8-51 in Mexico City

Date & Time: Dec 24, 1966 at 0430 LT
Type of aircraft:
Operator:
Registration:
XA-NUS
Survivors:
Yes
Schedule:
New York - Mexico City
MSN:
45633
YOM:
1962
Country:
Crew on board:
8
Crew fatalities:
Pax on board:
101
Pax fatalities:
Other fatalities:
Total fatalities:
0
Circumstances:
The approach to Mexico City-Benito Juárez Airport was completed by night. In poor visibility, the pilot-in-command failed to realize his altitude was too low and led the aircraft pass below the glide until it struck the ground. At impact, the undercarriage were torn off and the airplane broke in two before coming to rest in the Texcoco dry lake. All 109 occupants were rescued, 28 of them were injured. The aircraft was destroyed.
Probable cause:
Wrong approach configuration.

Crash of a Douglas DC-8-51 in Acapulco: 6 killed

Date & Time: Aug 13, 1966 at 0215 LT
Type of aircraft:
Operator:
Registration:
XA-PEI
Flight Type:
Survivors:
No
Site:
Schedule:
Acapulco - Acapulco
MSN:
45652
YOM:
1962
Country:
Crew on board:
6
Crew fatalities:
Pax on board:
0
Pax fatalities:
Other fatalities:
Total fatalities:
6
Captain / Total flying hours:
15712
Captain / Total hours on type:
1256.00
Copilot / Total flying hours:
13630
Copilot / Total hours on type:
7
Aircraft flight hours:
10030
Circumstances:
After an uneventful scheduled flight from New York, U.S.A. to Acapulco, Mexico, with an intermediate stop at Mexico City, the aircraft arrived at Acapulco International Airport at 0012 hours local time. It was then serviced and refuelled and took off from runway 10 at approximately 0114 hours on a local crew training flight. At about 0150 hours the aircraft reported over the station at 16 000 ft and requested clearance from the tower to carry out a simulated descent. Clearance was granted and the aircraft was instructed to report at 6 000 ft overhead which it did and was seen by the tower controller who then requested it to report on procedure turn. The aircraft reported on procedure turn at 2 500 ft and this was the last message received. At approximately 0215 hours explosions were heard and a fire was reported southeast of the airport. The wreckage was found on the slope of Mt El Salado, about 33 km from Acapulco Airport. The aircraft was totally destroyed and all six crew members were killed.
Probable cause:
Careless and untimely descent in the course of a procedure turn which wan continued below established minimum altitude. The following findings were reported:
- Weather was not a factor in this accident,
- The aircraft was carrying out a simulated descent approach procedure and the desCe2t from 2 500 ft was initiated in the middle of the procedure turn, whereas according to the standard procedure it should have been initiated on completion of the procedure turn when the aircraft was aligned with the runway. The aircraft's descent was continued below the minimum altitude limit until the aircraft struck the ground in a nearly level attitude, slightly banked to the right, with the undercarriage extended and 50° of flaps (instead of the normal 35°),
- No evidence of a malfunction or failure of the aircraft, its engines or equipment, or of a loss of control of the aircraft was found,
- Evidence of complacency in the supervision of the flight was found.
Final Report:

Crash of a Douglas DC-8-52 in Auckland: 2 killed

Date & Time: Jul 4, 1966 at 1559 LT
Type of aircraft:
Operator:
Registration:
ZK-NZB
Flight Phase:
Flight Type:
Survivors:
Yes
Schedule:
Auckland - Auckland
MSN:
45751
YOM:
1965
Country:
Region:
Crew on board:
5
Crew fatalities:
Pax on board:
0
Pax fatalities:
Other fatalities:
Total fatalities:
2
Captain / Total flying hours:
17966
Captain / Total hours on type:
497.00
Copilot / Total flying hours:
4200
Copilot / Total hours on type:
21
Aircraft flight hours:
2275
Circumstances:
The aircraft was making the first take-off of a routine crew training flight at Auckland International Airport, New Zealand. Time of departure was 1559 hours New Zealand Standard Time. All five occupants were seated on the flight deck. Shortly after rotation, the starboard wing dropped, the aircraft failed to accelerate and gain height normally and side-slipped inward until the wing tip struck the ground. The aircraft then cartwheeled clockwise about the nose radome and progressively disintegrated. Initial impact took place 3,865 feet beyond the threshold and 97.5 ft to starboard of runway 23, the active runway. Two crew members were killed and three others were injured. The aircraft was totally destroyed.
Probable cause:
The primary cause of this accident was,the incurrence of reverse thrust during simulated failure of No. 4 engine on take-off. That condition arose when very rapid rearward movement of the power lever (customary only on crew training flights involving simulated engine failure) generated an inertia force which caused the associated thrust brake lever to rise and enter the reverse idle detent. After lift-off, the minimum control speed essentially required to overcome the prevailing state of thrust imbalance was never attained and an uncontrollable roll, accompanied by some degree of yaw and side-slip in the same direction, ensued. When the condition of reverse thrust was recognized and eliminated,insufficient time and height were available to allow the aircraft to recover from its precarious attitude before it struck the ground.
Final Report:

Crash of a Douglas DC-8-43 in Tokyo: 64 killed

Date & Time: Mar 4, 1966 at 2015 LT
Type of aircraft:
Operator:
Registration:
CF-CPK
Survivors:
Yes
Schedule:
Hong Kong – Tokyo – Vancouver
MSN:
45761
YOM:
1965
Flight number:
CP402
Country:
Region:
Crew on board:
10
Crew fatalities:
Pax on board:
62
Pax fatalities:
Other fatalities:
Total fatalities:
64
Captain / Total flying hours:
26564
Captain / Total hours on type:
4089.00
Copilot / Total flying hours:
19789
Copilot / Total hours on type:
3071
Aircraft flight hours:
1792
Circumstances:
Flight 402 was a scheduled international flight from Hong Kong to Tokyo and Vancouver. It took off from Hong Kong at 1614 hours Japan Standard Time and was routed via Taipei, Kagoshima and Ohshima. At 1908 hours it flew over "Spencer Victor" at 25 000 ft and started to descend gradually; at 1912 hours it crossed "Rice Victor" at 18 000 it and two minutes later entered the Kisarazu holding pattern at 14 000 ft where it waited for an improvement of the weather conditions at Tokyo International Airport (TIA). At 1942 hours the flight notified Tokyo air traffic control that if the weather conditions failed to improve within 15 minutes, it would divert to Taipei (alternate airport). Ten minutes later, at 1952 hours the flight was advised by Tokyo ATC that the RVR was 2 400 ft and the pilot then asked for a clearance for approach and landing. The approach clearance was given and the aircraft proceeded to descend to 3 000 ft, in the holding pattern. However, the weather conditions at TIA worsened and the aircraft did not proceed with the approach. The pilot requested a clearance to divert to Taipei at 1958 hours and commenced climbing. At 2005 hours, while heading for Tateyama en route to Taipei the flight was advised by Tokyo air traffic control that visibility at TIA had improved to 4 mile with RVR 3 000 ft. Consequently, the pilot requested a clearance to return to Kisarazu and began descending from 11 500 ft. At 2011 hours the aircraft arrived over Kisarazu at 3 000 ft and began another approach under instructions of the GCA. At this time the flight was quite normal. When the aircraft was 8 NM from touchdown at an altitude of 1 500 ft, it was advised that there was a light tailwind 150015 kt and was cleared to land on runway 33R. The rate of descent for final approach was begun about 5.3 NM from touchdown at approximately 2012:58 hours. The aircraft was on course and on the glide path with a ground speed of approximately 174 kt, gradually decreasing to approximately 140 kt at 2 NM and 114 kt after passing 1 NM. When the aircraft reached one mile from touchdown, the GCA final controller noted that the aircraft was slightly below the GCA glide path and advised "20 ft low, level off momentarily". Nevertheless, the aircraft continued its approach 20 ft below and in parallel with the GCA glide path. After the aircraft passed the P.M. (precision minimum), the aircraft requested the intensity of the lights to be reduced. Shortly thereafter, the aircraft made a sharp descent and its main landing gear wheel struck No. 14 approach light 2 800 ft from touch- down point approximately in an attitude of level flight. Following this first contact, the aircraft struck the approach lights one by one until No. 3 damaging or destroying them, and at approximately 2015 hours crashed against the sea wall with the bottom of the fore-fuselage. Then, the aircraft was thrown over near the end of runway 33R, destroyed and caught fire. All 10 crew members and 54 passengers were killed while eight others were injured.
Probable cause:
The pilot misjudged landing approach under unusually difficult weather conditions. The visibility at Tokyo International Airport was reduced at the time of landing to less than half a mile by fog and smoke, RVR was in the order of 3 000 it. The aircraft carried out a GCA approach to runway 33R under very difficult conditions. It was considered that the approach was normal until a point located between 3 900 and 3 600 ft before the touchdown point. It then entered a steep rate of descent between 3 900 and 3 600 it before the touchdown point, it first struck an approach light 2 800 ft from the touchdown point in an attitude of level flight, then broke several approach light piers and crashed against the sea wall of the airport. The wreckage was thrown over the sea wall near the runway threshold and completely destroyed by the ensuing fire. The steep rate of descent was considered to be the result of an intentional manoeuvre of the aircraft by the pilot-in-command with a view to executing a final approach at a lower altitude than normal. Although no certain cause for the excessive descent which led to striking the approach lights could be determined, it was considered that the poor visibility due to illusive fog conditions that night misled the pilot-in-command in his judgement.
Final Report:

Crash of a Douglas DC-8-21 into the Lake Pontchartrain: 58 killed

Date & Time: Feb 25, 1964 at 0205 LT
Type of aircraft:
Operator:
Registration:
N8607
Flight Phase:
Survivors:
No
Schedule:
Mexico City – New Orleans – Atlanta – Philadelphia – New York
MSN:
45428
YOM:
1960
Flight number:
EA304
Crew on board:
7
Crew fatalities:
Pax on board:
51
Pax fatalities:
Other fatalities:
Total fatalities:
58
Captain / Total flying hours:
19160
Captain / Total hours on type:
916.00
Copilot / Total flying hours:
10734
Copilot / Total hours on type:
2404
Aircraft flight hours:
11340
Circumstances:
The flight, scheduled from Mexico City to New York City, with several intermediate stops, had just departed New Orleans at 0200. Three minutes later the captain acknowledged a request to change radio frequencies, but no further communications were received from the flight At 0205-40 the radar target associated with Flight 304 had disappeared from the scopes of both the radar controllers who were observing the flight. Moderate to severe turbulence existed in the area at the time of the accident. At 0159 46 the local controller in the tower observed Flight 304 commence the takeoff. The lift-off appeared normal, and at approximately 0201 he advised the flight to contact Departure Control, which was acknowledged. He estimated that the flight was two or three miles north of the airport when the lights disappeared into the overcast Voice communication and radar contact were established immediately between the flight and the departure controller who advised them to" . . turn right heading 030, be a vector north of J-37 (the planned route of flight)" While the flight continued on this vector, the departure controller contacted the New Orleans Air Route Traffic Control Center (ARTCC) The radar target was identified five miles north of the New Orleans VORTAC, and a radar handoff was effected at 0202 38. Flight 304 was instructed to "contact New Orleans Center radar, frequency 123.6 now." At 0203 15 the crew replied, "OK". This was the last transmission from the flight. At 0205 40, when no transmissions had been received from the flight, the center controller contacted the departure controller to verify that proper instructions had been given. During this conversation both controllers confirmed that the radar target associated with the flight had disappeared from both scopes, and emergency procedures were initiated shortly thereafter. The last position noted by the controllers was approximately eight miles from the New Orleans VORTAC on the 030-degree radial. The aircraft crashed at 14.5 miles on the 034-degree radial, in Lake Pontchartrain. The aircraft disintegrated on impact and all 58 occupants have been killed.
Probable cause:
The Board determines the probable cause of this accident was the degradation of aircraft stability characteristics in turbulence, because of abnormal longitudinal trim component positions.
Final Report:

Crash of a Douglas DC-8-54F in Sainte-Thérèse-de-Blainville: 118 killed

Date & Time: Nov 29, 1963 at 1833 LT
Type of aircraft:
Operator:
Registration:
CF-TJN
Flight Phase:
Survivors:
No
Schedule:
Montreal - Toronto
MSN:
45654
YOM:
1963
Flight number:
TCA831
Country:
Crew on board:
7
Crew fatalities:
Pax on board:
111
Pax fatalities:
Other fatalities:
Total fatalities:
118
Captain / Total flying hours:
17206
Captain / Total hours on type:
561.00
Copilot / Total flying hours:
8302
Copilot / Total hours on type:
390
Aircraft flight hours:
2174
Circumstances:
The Douglas DC-8 aircraft was on a regular scheduled flight Montreal-Dorval Airport (YUL) to Toronto (YYZ), Canada, scheduled to leave Montreal at 18:10. There were some delays in the boarding of the passengers and Flight 831 started its takeoff roll on runway 06R at approximately 18:28. Weather was reported as overcast, light rain and fog, visibility 4 miles, surface wind NE at 12 mph. The flight was instructed to report passing 3000 feet and 7000 feet on the climb-out from the airport. The aircraft took off normally, reported in at 3,000 feet and acknowledged a clearance for a left turn to St. Eustache. This was the last radio contact with the flight. The aircraft then deviated from its normal flight path about 55 degrees to the right and began a quick descent. At 18:33, 16.9 miles from the airport, the DC-8 struck the ground at a speed of 470-485 knots descending at an angle of about 55 degrees (+/- 7deg). The airplane plunged into the ground and totally disintegrated upon impact. There were no survivors among the 118 occupants.
Probable cause:
It is concluded that the actual cause of the accident cannot be determined with certainty. It is concluded that the most probable chain of events which occasioned the crash can be identified as follows. For one of the reasons which are set forth below, the pilot applied the near maximum available Aircraft Nose Down Trim to the horizontal stabilizer. The aircraft then commenced a diving descent building up speed at such a rate that any attempted recovery was ineffective because the stabilizer hydraulic motor had stalled, thus making it impossible within the altitude available to trim the aircraft out of the extreme AND position.
(a) The first reason which might have indicated to the pilot the necessity for applying, nose down trim could have been icing of the Pitot system as discussed in the Analysis of Evidence. While the experience and competency of the crew would likely have led them to recognize the fault in time to take corrective action, the possibility that this condition caused the application of AND trim cannot be dismissed.
(b) The second reason could have been a failure of a vertical gyro. The evidence indicated that it was possible to have a failure of a vertical gyro without an associated warning flag. If such a failure occurred and the aircraft was being flown with reference to the associated artificial horizon instrument it is likely that the pilot would be misled by the erroneous indication and could have applied nosedown trim. Aircraft CF-TJN was equipped with a standby artificial horizon located on the Captain's instrument panel and this cross reference together with the experience and competency of the crew would likely have led them to recognize the fault in time to take corrective action. Again, the possibility that this condition caused the application of AND trim cannot be dismissed.
(c) The third reason could have been an unprogrammed and unnoticed extension of the Pitch Trim Compensator. This would have had the effect of moving the control column back, the elevators up and the aircraft to a nose up condition. The pilot would likely have counteracted the pitch up force of the elevators by trimming the horizontal stabilizer to or near to the limit of the Aircraft Nose Down setting. The evidence shows that the simultaneous application of up elevator from the PTC and the application of as little as 0.5 degrees of Aircraft Nose Down trim on the horizontal stabilizer has an adverse effect on aircraft stability and can create a difficult control problem. The problems of instability and control are more serious as further AND trim is applied. In aircraft CF-TJN 2.0 degrees of AND trim was available and it appears that the pilot applied at least 1.6 degrees of the available trim. It is unlikely that the flight crew were aware of the serious stability and-control problems that we now know can result from the combination of extended PTC and AND trim, even if they had been aware that the PTC had extended. The aircraft would then be in a condition where a slight displacement from its trim point would lead to divergent oscillations. In other words, a minor change. of attitude, easily caused by the existing turbulence, would build up into large displacements. The inadequate control available to the pilot and the lack of an external horizon reference would likely result in the aircraft eventually assuming a dive attitude.
It is concluded that an unprogrammed extension of the Pitch Trim Compensator is the most probable cause for the pilot having applied Aircraft Nose Down Trim, which initiated the chain of events that culminated in the crash.
Final Report: