Singapore purchases 12 more F-15SG
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For conventional air engagements, right now it's: If you are in my sights, i'm probably in yours as well. Except that the defender has way more guns pointing at you.
ANYWAY these are all off topic!
24 Eagles + 4* CAEW. Hot but i think must wait until after budget day for more eagles.
The odd thing is that there's no air force recruitment ads these days. Ironically it's the NAVY that's recruting... I smell something new brewing...... -
Pilots and Planes on red alert standby has been going on as long as I can remember, not only in high tension but even in peacetime like now. I should not go into too much details, but we have a effective air cover to counter a surprise airstrike.Originally posted by seachfun:During high tension when plane & pilot standby, pilot is in the cockpit till next shift. Theoritical time to scramble off is around 1 min. You may verify with the source. -
multi purpose carrier... anyone???Originally posted by CM06:For conventional air engagements, right now it's: If you are in my sights, i'm probably in yours as well. Except that the defender has way more guns pointing at you.
ANYWAY these are all off topic!
24 Eagles + 4* CAEW. Hot but i think must wait until after budget day for more eagles.
The odd thing is that there's no air force recruitment ads these days. Ironically it's the NAVY that's recruting... I smell something new brewing......
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1 min.... quite tough unless the jet is already hot.Originally posted by seachfun:During high tension when plane & pilot standby, pilot is in the cockpit till next shift. Theoritical time to scramble off is around 1 min. You may verify with the source.
A ramp start up itself will take 1 min. Don't forget taxi time. -
i came across a CNN video clip on this topics yesterday.
did u know?updated 10:07 a.m. PT, Thurs., Jan. 10, 2008
WASHINGTON - An Air Force investigation of the crash last fall of an F-15C Eagle fighter jet concluded that a defective metal beam in the frame cracked, causing it to disintegrate during flight. A parallel examination found as many as 163 of the workhorse aircraft also have flawed support beams, or longerons.
In a report being released Thursday, obtained in advance by The Associated Press, Air Force investigators said they had found the sole reason for the accident was the faulty support beam, called a longeron, which failed to meet the manufacturer's specifications.
The investigation was led by Air Force Col. William Wignall. -
Point is? Those F-15Cs are manufactured probably even before I was born.
Our F-15SGs are brand new. ANd in a sense, its good that there is now awareness of the longeron fatigue failures. -
Came out in TODAY paper yesterday. F-15s affected were the A to D variants which are super old. The F-15Es were given the all clear soon after the entire F-15 fleet was grounded. F-15SG is based on the F-15E frame so if E is safe, so is SG.
Think about it lah, if the danger of the F-15SG falling apart is real, would RSAF actually be dumb enough to go ahead and risk it?
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SPECIAL REPORT: US Air Force returns F-15s to flight, but questions viability of fleet
By Graham Warwick
US Air Force Boeing F-15 Eagles have begun returning to flight, but the service says it is possible a portion of the fleet will never fly again. Some 40% of the fleet remains grounded, and the USAF continues to push for more Lockheed Martin F-22s to replace its air-superiority F-15s.
"I have a fleet that is 100% fatigued, and 40% of that has bad parts. The long-term future of the F-15 is in question," says Gen John Corley, commander of Air Combat Command. "The problem is systemic and goes beyond the F-15," he says, citing fatigue issues with A-10s and F-16s.
ACC has cleared 259 of the USAF's 441 F-15A-Ds to return to flight without restrictions after they passed inspections for manufacturing deficiencies that could potentially cause fatigue cracking of forward fuselage longerons.
The inspections followed the 2 November 2007 crash of a Missouri Air National Guard F-15C when the upper right longeron failed during air-combat training, causing the cockpit to separate from the fuselage.
Cracks were found in nine other F-15s where machining during manufacture had reduced the thickness of the longeron web below blueprint specification or where there is surface roughness that could cause stress concentration.
The 40% of the fleet that remains grounded have longerons that do not meet blueprint specification at one or more points, says Maj Gen Thomas Owen, commander of Warner Robins Air Logistics Center, the F-15 depot.
The affected aircraft were delivered between 1972 and 1985 and range from F-15As to F-15Ds. Corley says one of his reasons for grounding the fleet was that the problems did not appear to be restricted to one group of aircraft.
During the inspections, metal thickness was ultrasonically checked at 84 locations on each upper right and left longeron and if any one of the 168 data points was below specification, the aircraft remained grounded, he says.
Affected aircraft are now being analysed individually to determine if they can be returned to service with recurrent inspections or flight restrictions, or whether they must be repaired or scrapped.
An initial batch of 15 new longerons is being produced, Owen says, but the USAF has not decided which aircraft will undergo the repair. The cost to replace a longeron is around $250,000, he says.
Some of the F-15s are planned to be retired in 2009 as part of a force drawdown, but Corley says fatigue and manufacturing defects "put into huge question" the US Air Force's plan to keep 177 upgraded "Golden Eagles" in service.
"What are we going to have to do to keep them viable?" he says. "We were going to add combat capability to those aircraft, but instead we may have to spend billion on structural upgrades." The planned upgrades include active electronically scanned array radars.
Even before the Eagle broke up in flight, the US Air Force was pressing the Department of Defense for funding to buy additional F-22s beyond the 183 currently planned to replace its F-15s. "Can I buy more F-22s, can I buy F-22s at the rate I need, can I buy F-22s until F-35s are available? All options are on the table," says Corley.
F-15A-Ds are the principal aircraft assigned to the US air sovereignty mission and while they have been grounded the USAF has beeen using F-15Es, F-16s and F-22s. But this is interfering those units' preparations for deloyments to Afghanistan and Iraq, Corley says, adding: "We can only do it for a period of time."
DATE:11/01/08
SOURCE:Flight International -
PICTURES: Manufacturing defects caused cracks that downed USAF F-15
By Graham Warwick
Fatigue cracks started by manufacturing defects in a fuselage longeron caused the in-flight break-up of a Boeing F-15C Eagle on 2 November 2007, the US Air Force accident investigation has concluded.
Longeron cracks have been found in another nine F-15Cs, and manufacturing defects that could potentially cause fatigue cracking have been detected in a further 182 F-15A-Ds. All of these aircraft remain grounded.
Examination of the wreckage of the crashed F-15 revealed the right upper longeron, a critical load-carrying component in the forward fuselage, failed because of a fatigue crack that formed where the metal was thinner than specified in the blueprint.
Instead of being the specified 0.090-0.110in (2.3-2.8mm) thick, the flat top, or web, of the aluminium longeron that failed was as thin as 0.039in – less than a millimetre - in the area when the fatigue crack formed.
The thinning was caused when the longeron was machined by McDonnell Douglas during production of the aircraft, which was delivered in 1982. Similar manufacturing defects - undercuts, ridges or surface roughness that could potentially cause stress concentrations – have been detected in upper longerons in 40% of fleet.
This was by far the worst thinning of a web discovered by the fleet-wide inspections that followed the crash, says Maj Gen Thomas Owen, commander of Warner Robins Air Logistics Center, the USAFÂ’s F-15 depot.
Undercuts during machining thinned the web below blueprint specification © US Air Force
The accident aircraft had accumulated 5,700 flight hours, says Owen, or 11,000 “equivalent spectrum hours” taking in account the additional fatigue stress imposed by high-G manoeuvring. But the longeron was projected to last 31,000h, well past the life of the aircraft, he says.
In the 2 November in-flight break-up, the cockpit separated at canted fuselage station 377, where the forward and aft sections of the two-piece upper longerons are spliced. The fatigue crack had formed just forward of the splice, in an undercut produced when a sloping transition was machined in the underside of the longeron.
Investigators say the crack started on the underside of the longeron, working its way upwards and outwards through the over-thin web until it reached the outer “posts”, which carry the bulk of the forward fuselage loads.
Fatigue crack spread through the web, and weakened longeron fractured © US Air Force
Weakened by the crack, the posts fractured as the aircraft pulled almost 7.8G in an air-combat manoeuvre. When the upper right longeron failed, the other three upper and lower longerons could not carry the loads and the forward fuselage separated.
Owen says the USAF has ultrasonically inspected 84 specific locations on each upper longeron on every F-15A-D. “That’s 168 data points per aircraft, and if any one is under blueprint, then the aircraft remains grounded.”
Acknowledging its “conservative” approach, the USAF says each grounded aircraft will be individually analysed to determine if it can be returned to flight with recurrent inspections or flight restrictions, or whether it must be repaired or retired.
Detailed analysis is under way at the Air Force Research Laboratory to determine the rate at which the fatigue cracks spread, so that requirements for recurrent inspection of affected longerons can be established.
Examples of longeron cracks found in other F-15s © US Air Force
While the USAF has not decided which, if any, aircraft will be repairs, Warner Robins is manufacturing an initial batch of 15 longerons at a cost of $15,000. Owen says replacement of the longeron in an aircraft will cost $250,000.
Owen also says the USAF will also conduct detailed inspections of other primary structure in a sample of the F-15 fleet to determine whether similar manufacturing defects exist in other critical areas of the aircraft.
DATE:11/01/08
SOURCE:Flightglobal.com -
VIDEO: USAF reconstructs F-15 accident
By Graham Warwick
On 2 November, 2007, a Missouri Air National Guard Boeing F-15C had just entered a mock dogfight when the pilot felt something was wrong with his aircraft. Seconds later, the Eagle broke in two and the pilot ejected from a tumbling cockpit.
Using HUD camera recordings and other data, the US Air Force has reconstructed the circumstances surrounding the accident, which occurred during routine basic fighter manoeuvre (BFM) training involving four F-15s.
The mishap aircraft, serial number 80-0034 and call sign Mick 2, was engaged in one-on-one air combat manoeuvres with the flight lead. The initial engagement was uneventful.
But, soon after beginning the second engagement, in a nearly level right-hand turn at about 450kt and just under 7.8G, the mishap aircraft began shaking violently from side to side.
The pilot disengaged, calling “Mick 2, knock it off!” while simultaneously rolling wings level and reducing to 1.5G. Within seconds the forward fuselage separated from the rest of the aircraft.
Hearing the “knock it off!” call, the flight lead looked over his shoulder and saw the F-15 in two pieces. He told the mishap pilot to eject, but the pilot did not hear him and was still unaware his aircraft had broken up.
The first sign of trouble, according to the pilot, was a whooshing sound and debris floating in the cockpit. Thinking the aircraft had lost pressurization, he reached for the oxygen regulator only to be slammed forward as the separated cockpit slowed from 450kt with a force of 4-10G.
The flight lead, meanwhile, commanded the other two F-15s to disengage and climb to a safe altitude. He then called: “Mick 2’s aircraft just broke in two.” Only when he saw the parachute open did he know the pilot has escaped the stricken aircraft.
The US Air Force has released a video reconstructing the accident. It includes HUD camera video and cockpit audio recordings recovered from the mishap aircraft. As the engagement begins you can hear the pilot grunting under G strain and the tone of a missile lock. You can also hear the tension in the flight leadÂ’s voice until he sees the parachute open.
The video shows the two F-15s manoeuvring. The window at the top right shows the flight leadÂ’s view of the mishap aircraft as it manoeuvres then breaks up. Along the bottom are dials showing (left to right) angle of attack, G, airspeed, attitude and altitude. And, in the bottom right corner, is the HUD video from the mishap aircraft.
DATE:11/01/08
SOURCE:Flightglobal.com -
VIDEO: Recreating the Eagle's final moments
By Graham Warwick
Using eyewitness reports, HUD camera video, debris analysis and the pilotÂ’s own testimony, BoeingÂ’s Phantom Works research organisation has recreated the break-up of the US Air National Guard F-15C in the skies of Missouri on 2 November.
“This is as close as science can get us to what actually happened,” says Gen John Corley, commander of US Air Force Air Combat Command, commenting on the computer-generated animation. “We are lucky the pilot is still alive.”
The animation, which is slowed to one-fifth the speed of the actual event, shows the in-flight break-up of the F-15 from five different views. Each segment runs from the initial nose shimmy as the longeron fails to the pilot’s ejection from the tumbling cockpit – a sequence of events that lasted mere seconds in the real event.
When the upper right longeron breaks, the other three longerons cannot carry the load and the forward fuselage structure begins to fail. As the cockpit separates from the rest of the aircraft, it “wins the tug of war” and takes the canopy with it.
The pilot is thrown forward as the separated cockpit slows from 450kt with an “eyeballs out” force of 4-10G. At this point, disoriented by the brutal deceleration, he is still unaware his aircraft has broken in two.
As the cockpit tumbles, windblast rips off the canopy, the transparency fragmenting. The departing canopy rail strikes and shatters the pilot’s upper left arm. “There are paint marks on his flight suit,” says Corley.
Unable to initiate a two-handed ejection, but not knowing why his left arm will not respond, the pilot ejects using his right hand. Although almost inverted when he ejects, the Aces II seat “works as advertised”.
Now “headless”, its landing gear deployed by gravity after the departing cockpit pulled the cables releasing the uplocks, the stricken F-15 enters its final moments. The two sections of the aircraft came down a quarter to half a mile apart.
DATE:11/01/08
SOURCE:Flightglobal.com -
shouldnt the manufactuerer foot the bill for the repair? its their manufacturing error.....
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well. does this mean that the airframe would have a shorter life span? And higher upgrade cost after certain flight time?
If the life cycle of the plane is shorter that would means airforce would have to address the gap between the project life cycle and replacement. other than the budget issue. -
on the contrary... with this incident... the new F-15SG currently in production would have even stringent check and specifications to the affected area... making the F-15SG more reliable.Originally posted by Arapahoe:well. does this mean that the airframe would have a shorter life span? And higher upgrade cost after certain flight time?
If the life cycle of the plane is shorter that would means airforce would have to address the gap between the project life cycle and replacement. other than the budget issue.