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John - a great explanation for the non-technically-minded! Good photo as well.
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lomapaseo Quote: Engine surges are a common manifestation of many types of engine problems some of which are as temporary in nature as a tired engine. The flight manual for the particular engine model is based on experience in how to deal with it. In some cases it does permit continuation of flight. The crew training should have covered the identification and response at the flight deck level. What the ground sees and hears is what has been reported above. It's up to the pilot to recognize the difference between a recoverable engine surge and an engine which is on fire and requires shutting it down or discharging a fire bottle. That's why they put engine gages in the cockpit and train pilots how to respond. I'm not aware of what ground controlers are trained to say when they hear a bang look up and see fire and smoke trailing an aircraft. I'm glad at least that they don't just stare and bite their lip. Many ac have procedures for non annunciated fires. what crew would choose to ignore reports of an engine fire from fellow professionals? Thats why accurate reporting is essential. John- great pic. burners on, go! |
For the controller who transmitted that it was a fire: IMHO the pilots are busy diagnosing the surge, and then taking the appropriate action. They are in no doubt that something is wrong! Perhaps "Speedbird do you require assistance" would have worked slightly better? The answer would almost certainly be 'standby' We, in ATC, are not going to sit there at the time of the incident and discuss whether it was an engine surge or an engine fire or a fuel leak which has ignited, we WILL report to the pilots what we have observed. We don't expect a response of anything other than standby, we know the pilots are busy dealing with the situation. This is what comes out of our TRUCE* sessions, which pilots attend, pass the relevant info but don't hassle. I was in the Tower a few years back when a BA 777 departed with fuel gushing from under the wing box. We told the pilots what we had observed and their response at the time was they had no abnormal indications. *TRUCE = Training in Unusual Circumstances and Emergencies |
I was about 200m from the aircraft when it rotated and saw / heard / felt the surges. At the time considered it to be a fire the surges were closes together and created a long substained flame for a good 3-5 seconds. The controller and myself both at the same time advised on the tower frequency that the the engine maybe on fire, This was to advise the pilot of a visual state of the engine, no doubt he had alarms and bells going off in the cockpit anyway,after a swift Roger he contuned to declare a mayday and suspected engine fire. after dumping fuel he returned and downgraded his situation to a PAN and engine failure. I can confirm that the Captain (possibly a former Chief Concorde person), reported a fire on or shortly after rotation. A Mayday call was made stating that there was an engine fire. The aircraft was vectored out to The Solent in order to dump fuel. At that point the Captain downgraded the Mayday to a PAN. It began dumping fuel at around 6000 feet, and in order to stay within controlled airspace it climbed to 11000 feet. There was an initial request for an hour in a racetrack pattern for fuel dumping which was subsequently reduced to 40 minutes. |
John's excellent photo given a polish in Photoshop
http://i153.photobucket.com/albums/s...an/harrier.jpg |
Am I the only one who thinks Walker Texas Ranger's question was a valid one?Or am I way too cynical?
I wasnt on the flt deck so I dont know what happened but the declaration of mayday is a very clean way to dodge the "commercial decision" accusation. If you're a BA 744 skipper with a surge out of LHR you probably need to tread very carefully.The eyes of the world are watching.Will they do what they did out of LAX?Well,of course not.They arent going to continue,we know that for sure.But if no mayday is declared(surge followed by shutdown on a 4 engine a/c is not a mayday)then how do they get round the "dump all that fuel and return home just for a surge?"Its a tricky one...you have my sympathies. but if some one reports the engine on fire[it wasn't] the crew is pretty much forced to put a fire bottle in. |
Think about this,
Intermittent fire indication on an engine. Do you put the bottle in or not? Tailpipe fire on the ground is a different game. Irrelevant to this discussion. "Flame seen on the left side" is not the same as "engine on fire" the crew would react differently even if the don't mean to. It’s why we never use the word "panic" in briefings. i.e. "no need to panic". Once the words are out there they will make a difference. |
What aircraft captain could be conned into departing an airfield to dump fuel when he has an engine or wing on fire. Good way to lose a wing while he dumps. Of course if the shutoffs and fire extinguishers positively put out the fire THEN use your SOPs. But be careful - I once had an engine ( imbedded) fire which spread to and weakened the wing structure before that dreaded red warning light resulted in the discharging of the fire bottles to successfully extinguish.
Otherwise get back on the ground immediately if not sooner. Specifications for maximum landing weight are predicated on a maximum vertical sink rate of usually 10 ft per second. 10 fps will always feel like a heavy landing. If in an emergency you need to land above specifications then you just have to be progressively more careful with your sink rate at touch down the greater your landing weight is above the normal maximum, simply to preserve the continuing integrity of the landing gear. Some mathemagician may be able to come up with the reducing sink rate numbers as your weight goes above max for landing. I think there may be a factor squared in there somewhere. The only other consideration I can see concerns the increasing touch down IAS with weight plus what you might add on 'for mum and the kids'. This increased IAS is largely irrelevant as it will be such a small component of those things which affect landing gear capacity. |
Were you piloting that Harrier ,John?
:eek: |
V ~ (W2/W1)^.5
Vs proportional to root W e.g. Double the weight, Vnew = 1.414 x Vold |
Thank you for the polish Rob. I tried to PM you but it said your box was full. Dunno if that is right but I would love a copy!
autothrottle. Yep. |
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