I have been reading the Preliminary Report of the Convair Pretoria Accident.
This report was issued by the Accident and Incident Investigative Division of the South African Civil Aviation Authority.
The 3 Investigators responsible for the report were local engineers of which only the lead engineer " had done some flying ".
The report basically tries to blame the Australian pilots but it is full of errors, inaccuracies and unwarranted opinion.
For example the First Officer, a highly regarded Qantas A380 training captain, was accused of not being type rated on the Convair. Yet I can see on page 4 of his Australian ATPL under Type Qualifications - C340/440 above A380 and B747. Also this same crew two years previously had ferried the same model Convair to Australia.
What is most disturbing however is that the 3 engineer investigators appear to have no understanding of twin piston engine aircraft climb performance in the event of an engine failure.
Twin engine jet aircraft have a required climb performance capability in the event of an engine failure after takeoff. Piston twin engine aircraft however may not climb safely away on one engine.The single biggest improvement in aviation safety has been the switch from piston to jet engines. Jet engine stress is rotational inertia unlike the harsh reciprocating forces in a piston engine. In two thousands hours on RNZAF Sunderland flying boats I experienced 4 engines failures 2 of which were partial. In 20,000 plus subsequent hours on jet aircraft I have up to date only experienced 1 failure which was a bearing failure in a Learjet engine and which I immediately shutdown to avoid damage.
The elevation of 4,100 feet at Pretoria and a temperature of 20 degrees C meant a reduced engine power output from a density altitude of 4,700 feet. Plus 19 passengers and nearly 4000 lb of fuel suggests that there was insufficient performance available on one engine to safely climb away.Pilots of piston twin aircraft are taught that if an engine fails before selection of gear up then close the throttle of the remaining engine and land straight ahead. If the engine fails after selection of gear up, which appears to be the Convair case, then the pilot is committed to climb away at the safety speed.
The Convair engine was a partial failure that progressively got worse. Pilots are taught before all else to fly the aircraft and airmanship in this case meant using what power was available from the failing engine, even if it was on fire, to assist in getting to a safe altitude to perform an emergency return to the field for landing. That they managed to get to 800 feet is testament to this fact.
The report slays the pilots for not carrying out the emergency procedure of shutting down the engine. To do so as the investigators state would probably have resulted in a more rapid performance decay and possibly loss of control and crash with the death of all on board. That the pilots managed, in a no win situation, to mitigate the forthcoming consequences by keeping control means they should be lauded. They importantly crashed under control in a nearly wings level attitude that unfortunately resulted in only the one fatality of the Flight Engineer, but saved the rest.
Another disturbing feature of the report is that the investigators, with no formal CRM training, confused the standard airline identification and confirming procedure ( avoids error ) as the pilots being unsure of what was happening. These 2 pilots are Senior Qantas Check and Training captains which includes them teaching human factors and CRM.
This report is severely flawed. The investigators should have sought the advice from experienced airline pilots. That they did not do not means in my opinion that the report is worthless.
CAS should request to the South African CAA a formal review of the report with a view of ensure the final report does not contain these many errors and unqualified opinions.
BYRON BAILEY
www.captainbyronbailey.com