Rovos Rail CVLP at Pretoria on Jul 10th 2018, engine problem
Last Update: August 28, 2019 / 14:33:13 GMT/Zulu time
Incident Facts
Date of incident
Jul 10, 2018
Classification
Accident
Cause
Engine problem
Aircraft Registration
ZS-BRV
Aircraft Type
CONVAIR CV-440 Metropolitan
ICAO Type Designator
CVLP
Probable Cause/s
During take-off, the left engine caught fire and the crew continued with the flight without securing the left engine as prescribed in the aircraft flight manual (AFM). The crew declared an emergency and attempted to return to the aerodrome, however, they lost control of the aircraft and collided with power lines prior to crashing into a factory building.
Contributory Factors:
- Pre-existing damage to the cylinder No 13 piston and ring pack deformation and, most probably, the cylinder No 7’s fractured exhaust valve head that were not detected during maintenance of the aircraft.
- Substandard maintenance for failing to conduct compression tests on all cylinders during the scheduled maintenance prior to the accident.
- Misdiagnosis of the left engine manifold pressure defect as it was reported twice prior to the accident.
- The crew not aborting take-off at 50kts prior to reaching V1; manifold pressure fluctuation was observed by the crew at 50kts and that should have resulted in an aborted take-off.
- Lack of crew resource management; this was evident as the crew ignored using the emergency checklist to respond to the in-flight left engine fire.
- Lack of recency training for both the PF and PM, as well as the LAME.
- Non-compliance to Civil Aviation Regulations by both the crew and the maintenance organisation.
The SACAA analysed that neither pilot was licensed to operate a South Africa registered Convair 340/440. The pilot flying was validated only to fly single engine aircraft, however, no multiengine aircraft, the pilot monitoring was licensed to fly multi engine aircraft, however, was not type rated on the Convair until later (however, this was not added to his license).
The Licensed Aircraft Maintenance Engineer (LAME) was properly certified to conduct maintenance on Convair 340/440 aircraft. The SACAA stated however:
There were no records to indicate when last the LAME had undergone a recurrent training/competency check as required by Part 145.01.11 of the Civil Aviation Regulations. The Aircraft Maintenance Organisation (AMO) could not provide the investigators with the training records of the LAME who was responsible for the maintenance of the Convair 340/440 aircraft. The LAME had misdiagnosed the manifold pressure defect by always removing the manifold pressure gauge whenever there was a left engine manifold pressure defect which was reported twice prior to the accident flight.
The SACAA analysed with respect to the aircraft:
Prior to this accident, the aircraft was last flown on 22 February 2018 and had 18115.1 flying hours. It was then parked for five months before it was flown again on 10 July 2018. The aircraft was being sold and the contract indicated that the aircraft would remain on the RSA register under the registered owner’s name until it was delivered to the new owners in the Netherlands. The new owners were to take delivery of the aircraft in the Netherlands.
The maintenance records revealed that on 26 February 2018, the AMO had recorded the defect of a manifold pressure gauge indication on the No 1 engine which was sticky. As a method of rectification, the manifold dual pressure gauge was removed, cleaned, sign off and refitted to the aircraft. On 5 May 2018, the same defect was recorded by the AMO and, again, the manifold dual pressure gauge was signed off as repaired and refitted. The manifold dual pressure gauge was removed twice (in March and July 2018) over a period of four months due to the left engine manifold pressure defect. During the engine inspection and examination, it was evident that the pre-existing damage on cylinder No 7 and cylinder No 13 were the cause of the left engine manifold pressure defect. The LAME misdiagnosed the manifold pressure indication defect by always removing the manifold dual pressure gauge whenever there was a left engine manifold pressure indication defect which was reported twice prior to the accident flight.
The engine No 1 manifold pressure drop, as reported by the crew during the take-off roll, was the result of a fractured No 7 cylinder exhaust valve head which subsequently caused backfiring. This explains the flames by the engine cowl flaps above the cowling.
During take-off, fire was seen on the top front side of the left engine cowling and exhaust area (Figures 2/3). The ATC stated that the aircraft continued in a northwesterly direction from the aerodrome over Bon Accord Dam at approximately 2 to 2.5 track miles and at a height of about 800 feet AGL, indicating a rate of climb of 600 to 700 feet per minute (fpm). The ATC confirmed to the investigators that the left engine had caught fire and that the crew had broadcasted a ‘MAYDAY’ call; however, when the crew broadcasted ‘MAYDAY’ they did not indicate the nature of the emergency that they were facing. This statement was confirmed by the recordings of the cockpit GoPro camera that was installed in the cockpit at the time of the accident. Although the left engine caught fire during the take-off roll, the crew continued with the flight and did not abort the take-off. Evidence obtained from the Gopro video camera installed in the cockpit showed the LAME giving the PM the quick reference handbook (QRH). However, the PM elected to ignore and not use the QRH for procedures to be followed during an emergency in-flight engine fire as was the case during this accident flight. This, therefore, explains why the left engine continued to be on fire until the aircraft impacted the ground.
Pilots flying multi-engine aircraft are trained to shut down the engine whenever an engine catches fire or whenever the crew suspects fire in the engine. The engine fire in-flight checklist required that the crew shut down the left engine that was on fire and that the left propeller be feathered. The PF and PM never followed the engine fire in-flight checklist and, as a result, the left engine that caught fire was never shut down or the propeller feathered. Post-accident examinations revealed that the left propeller had not been feathered prior to impact with both engines’ settings consistent with engines at take-off or climb.
The aircraft continued with its take-off and climbed to 800 feet AGL (with the left engine still on fire and not secured) before turning right after being cleared by ATC to return to the aerodrome due to the emergency. At this stage, the crew were just observing the LAME who was continuously operating the engine controls and overhead panel switches. This is evident on the Gopro video camera that was installed in the cockpit. Crew resource management was not observed as none of the crew attempted to use the emergency procedures checklist to respond to the inflight left engine fire.
The aircraft made another right turn (base leg) while losing height. It continued in that trajectory and the PF lost aileron control. This occurred due to the weakening of the left-wing rear spar because of fire damage that caused the attachment rivets of the aileron cables to melt, resulting in the cables being slack and, thus, loss of aileron control. The loss of aileron control led to the crew losing control of the aircraft and the aircraft colliding with power lines before impacting the factory building.
This resulted in the left aileron deflecting slightly up and a left roll. This left roll was exacerbated by the left engine operating at partial power loss due to cylinder No 7 and No 13 malfunctioning while the right engine was at full power. This caused a left yaw as a result of the asymmetric engines and required the PF to always make the right rudder input to correct the left yaw. See Appendix C. This resulted in the crew losing control of the aircraft.
The aircraft continued in that attitude while still losing height and impacted the electrical power lines (which were 30 metres high) before impacting trees in the factory yard, the vehicles parked outside the factory building and the factory building with its left wing. The aircraft damaged the factory building as it impacted the centre of the building. The in-board left wing had also separated and was found behind the factory building with its engine a few metres behind the left in-board wing. The right engine had also separated and was found a few metres to the left of the left wing’s position. The aircraft continued for a few metres before impacting the raised ground and stopped at the point of impact. The aircraft broke in two places/points and there was evidence of fire damage on the right side. The right fuel tank still contained fuel which was drained a day after the accident.
The LAME was fatally injured, while the crew, two passengers and four other persons on the ground sustained serious injuries. The rest of the passengers and four other persons on the ground had minor lacerations.
The last maintenance on the engine completed on 6 July 2018, indicated that the AMO had conducted compression tests on all cylinders for both engine 1 and 2 in accordance with the prescribed maintenance schedule (AMS) J15/09/427. The damage found on piston crown cylinder No 13 and Cylinder No 7 during the engine teardown inspection showed that the damage had existed prior to the accident. This explains the manifold pressure defect that was recorded in March 2018 and on 6 July 2018 prior to the accident. This was a clear indication that not all the cylinders had been subjected to the compression tests as was required during the A, B and C maintenance checks completed four days prior to the accident.
The failure of the No. 7 cylinder exhaust valve led to the cylinder cooling fins overheating, thus, causing the failure of the cylinder housing.
The failure of the exhaust valve and its housing led to the continuous fire coming from the cylinder through the chamber in the No 7 cylinder, given that the engine operates at a fairly high RPM. That resulted in the front main spar weakening/flaking and the damage to the aileron pulley attachments failing because of the mounting rivets melting. The melting of the rivets resulted in the pulley attachments falling into the wing and slacking the aileron control cables, which caused the aircraft to roll to the left.
The fire started in the left engine and evidence showed that the No 7 cylinder was the one with the most damage and was the source of the left engine fire. The fire continued burning through a hole on the No 7 cylinder, causing damage to the front wing spar and the left aileron pulley attachment point, melting the attachment rivets.
As a result, the left aileron control cables slacked and the aileron deflected slightly up. With the left engine operating at partial power due to damage and failure of cylinder number 7, the aircraft started rolling to the left. The opening of the left engine cowl flaps in-flight increased the intensity of the engine fire and the left roll.
Piston No 13 was found with carbon build-up, damaged piston crown and oil rings, indicating that cylinder No 13 was not operating effectively. The damage on the piston crown and oil rings would result in the loss of pressure in this cylinder and the left engine not operating at optimum power.
The left engine continued to operate at partial power with the propeller not feathered while the right engine was on full power. Moreover, a non-feathered propeller could induce a high parasite drag on an aircraft performance. The fact that the left engine propeller was never feathered is revealed in the GoPro video camera wherein the crew never discussed securing the left-hand engine.
The right-engine settings were generally consistent with the engine being at full power, which was operating normal, and the right propeller’s pitch was consistent with a high rotation power setting.
Approximately five litres of fuel was drained from the right-wing tanks at the accident site and the fuel was sent for examination. The fuel was consistent with AVGAS 100LL, which was free from contamination. The fuel test report indicated the following: fuel density — 0.717; temperature — 16.5°C; density correction — -0.0029 and 0.7141; batch density — 0.7142 and difference (1) — (2) ± good. The test results revealed that the fuel was good and clean. Two aircraft were refuelled on the same day from the same tank that was used to refuel ZS-BRV and no anomalies were reported. Oil and water methanol samples were examined and found to be within specifications and without contamination.
Incident Facts
Date of incident
Jul 10, 2018
Classification
Accident
Cause
Engine problem
Aircraft Registration
ZS-BRV
Aircraft Type
CONVAIR CV-440 Metropolitan
ICAO Type Designator
CVLP
This article is published under license from Avherald.com. © of text by Avherald.com.
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