Mirage Flame out.."Creditable Performance"
Some time ago over a few quiet ones with a friend we were discussing his previous life as a Mirage pilot. He told me the story of a low level intercept(2 RAF Phantoms) and subsequent engine flame out over Singapore.
Recently I came across the article below, Volume 2, No 7 from 1974 Flight Digest
Brief
During an ADEX a Mirage was scrambled to 10,000 ft for Combat Air Patrol. Total fuel load was 875 gallons. After approximately 25 minutes airborne, fuel configuration considered normal, the pilot was directed to intercept two low level aircraft. The afterburner was ignited and speed increased to 600 kts during the descent to 1000 ft AGL for interception. This profile was maintained for about 3 minutes until nearly overhead Tengah when the pilot noticed that the 130 gallon fuel warning light was on and both fuel gauges were oscillating and falling rapidly from the 60 gallon mark, with the debit reading over 300 gallons.
The intercept was abandoned and a 270 degree climbing right turn made to 1500 feet, to position for a short final initial runway 36. Fuel gauges were now reading erratically , so the pilot elected to make a straight in approach. Passing 1000 feet, the master fail and fuel lights came on and the engine flamed out. From this position the pilot assessed that the approach could be continued as a forced landing. With 200 knots over the threshold a normal touchdown was made and the drag chute deployed at 170 knots. Gentle braking stopped the aircraft clear of the runway.
Cause
This incident was caused by a defective fuel filter element. During manufacture an adhesive sealant had been applied internally to the base of the element. A ¾ inch diameter by 1/8 inch thick plug of this substance had become detached inside the element barrel and, under the influence of compressor outlet air flow, had moved down the barrel until retained by an inernal flange at the output end, thus forming a perfect seal. To avoid further incidents of this nature STI's Mirage/261 and 262 were raised to check the airworthiness of other Mirage aircraft and to remove any faulty components from service.
Comment
Without going into details of the fuel management in Mirage aircraft, it seems that the failure was either triggered by or coincident with afterburner ignition at the start of the low level intercept. An earlier failure would have prevented transfer of fuel from the external tanks. The failure reduced available fuel from about 590 gallons (at the beginning of the intercept) to 172 gallons, ie to 2-3 minutes at 60-70 GPM fuel-flow in full afterburner. The IAS and distance travelled during the intercept, 25-30 NM at 600 KIAS, also confirm that the period from failure to flame-out was barely three minutes.
Very little time elapsed between the pilot noticing the 130 gallon warning light until flame-out occurred, suggesting that the light had been on previously, probably for less than two minutes. Under the circumstances, the pilot's failure to see the light immediately is not surprising. The final phase of any intercept, particularly a low level high speed intercept, demands the pilot's complete attention. Additionally, the intercept occurred on an easterly heading with the sun high and behind the pilot, reducing the effectiveness of the light.
With the illumination of the 130 gallon warning light, the pilot followed the appropriate Mirage emergency procedure. As cockpit indications showed a progressively deteriorating situation he quickly correctly reassessed his position. His decisiveness and sound judgement undoubtably saved the aircraft.
The pilot is to be commended for his skilful handling of a nasty situation. Quite deservedly, the pilot's log book has been annotated with a creditable performance endorsement in accordance with ABO A5/7, para 8,
The wording is as follows:
'After a fuel pressurization failure which produced an emergency fuel situation, Flg Off XXXXX acted creditably in that he recovered the aircraft to Tengah airfield after the engine flamed out, due to exhaustion of available fuel.'