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Aviation History
1983
1983 - 0351.PDF
OFFICIAL ORGAN OF THE ROYAL AERO CLUB PRIVATE FLIGHT Fuel mishandling led to Islander crash LONDON When an Islander's port engine failed soon after take off, it would have been better for the pilot to have aban doned the climb and landed straight ahead, says the DoT Accidents Investigation Branch in its latest report (No. 7/82). The pilot and eight para chutists on board escaped unhurt in the subsequent impact. Fuel mismanagement caused the port engine failure, but a factor in the accident was the pilot's decision initially to continue the take off. When the port engine failed he raised the flaps and then started to feather and shut it down, but according to the pilot the starboard engine then started to lose power, and the Islander was a financial write-off in the subsequent very heavy land ing. While the port engine was found to have failed from fuel starvation, there was doubt as to whether the pilot was mistaken in assuming the starboard engine had also lost power. The AIB had to estab lish, says the report, why the pilot considered that both engines had failed, and why such a well-trained and experienced pilot (he was a RAF Hercules captain) was then unable to land straight ahead with 1,000m available. Before answering those queries, the port engine's fuel starvation can be accounted , for fairly easily. The Islander's tip tanks were in ' use for take-off, and in fact , the aircraft had been parked for about two days with the ' fuel selectors in the tip tank . position. The AIB concludes that, since the aircraft spent 1 much of this time parked in a , wing-low attitude, there had been a considerable fuel cross- ' flow from the port to star- , board tank. Investigation showed that probably only 3i : US gal were in the port tip tank at the time of take-off. Apparently the pilot concerned had assumed that the fuel switches were selected to main tanks, as was the usual practice at the para chute centre. The AIB recom mends that switching the fuel sectors to "off is included in "checks after stopping" in the Flight Manual; this would also have prevented the fuel transfer from one tank to the other while the aircraft was parked on a slope. It also recommends that Islander tip/main selector switches are modified to emphasise when fuel is being drawn from the tip tanks. The AIB's analysis of the pilot's actions after the port engine failed makes some important points about handling engine failures after take-off in light twins of the Islander class, especially when flown by pilots more used to larger aircraft with their far superior engine-out performance. As soon as the port engine failed (at single-engine safety speed plus 15kt) the pilot's first reaction was to "clean up" the aircraft by raising the flap and continue the climb. As he started to feather and shut down the port engine, he thought that the starboard engine was also starting to fail. It was later established, however, that the starboard engine continued to rotate under power until impact. If an engine fails in a Performance Group A aircraft after decision speed has been reached, the take-off must be continued. But the Islander is a Group C aircraft, where the requirements only call for climb performance assuming that both engines will be oper ating until at least 200ft. When the Islander's port engine failed it should have been capable of a shallow climb gradient (about Is per cent), but before the engine was feathered this climb would have been degraded by drag from the windmilling propeller, plus the absence of the rear port door (removed for parachuting). With this removed, most of the engine noise appears to come from the port side. When this noise died with the port engine fail ure, it could well have added to the pilot's illusion that the other engine had also failed, says the AIB. With 1,000m of un obstructed grass in front, the aircraft would probably have survived intact if the pilot had Beech's Sierra (left) and Sundowner are among 230 types to be featured in our International Private Aircraft Directory (March 12 Issue) decided to land straight ahead as soon as the port engine failed. In the end he had little time available to arrest a very high descent rate and consequent heavy landing. But at the end of a report, in which the pilot comes in for a fair amount of criticism, the AIB does commend him for his post-crash actions in en suring the safety of the passengers and aircraft. Schempp-Hirth develops "re trieve engine" GERMANY German manufacturer Schempp-Hirth is developing a retractable engine for its sailplane range, designed for retrieving or "get you home" flights under power at the end of a soaring flight. While the two-stroke layout is similar to the engines of conventional single-seat high-performance motor-gliders such as the Pik 20E and Janus CM (mounted on a beam which retracts into the top of the fuselage) it is much smaller, since no self- launching performance is claimed. Smaller size also comes from a five/six-bladed folding propeller. The idea is that the sail plane is launched by conventional aerotow or other means and later deploys its engine either to return home, or as required. The largest version will add some DM17,850 to the cost of a Nimbus or two-seat Janus, with DM15,750 for a lighter unit on the 15/16-metre Ventus. UK dealer is Southern Sail planes, telephone 0488 71774. National decision supports GA airfield Planning applications and public enquiries are not renowned for favouring general aviation in the UK, but a recent decision by the Secretary of State for the Environment supports the preservation of an active GA airfield, stresses its value as a regional amenity, and sets an encouraging note for any future disputes involving GA. The airfield in question is Ipswich Airport, which is the nearest airfield to the eastern seaports of Harwich and Felixstowe (responsible for a sizeable proportion of UK imports) and accounts for some 35,000 annual move ments. A planning application to allow its present lessee to build a superstore devel opment around the site would have resulted in the loss of one of two runways and a reduction in activities. The Department of the Environ ment has now rejected this in its decision on a public inquiry held two years ago, and supports the airfield users' viewpoint that the devel opment would have reduced safety, led to a possible 20 per cent drop in flying, and loss of business. In its decision the Dept of Environment points out that the airport "would be seri ously prejudiced by the proposals", and adds that "the future of the only general aviation airfield in the county is of more than local importance." Currently based at the airport are two public transport operators, three full-time flying schools, two approved maintenance com panies, and a parachute centre. FLIGHT International, 26 February 1983 521
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