Indonesian Airforce C-130 crash
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Originally Posted by aseanaero
Thanks Arendiii,
Why I ask is I read once that flap settings was one of the factors in the C-130A fire bomber accident , apparently the wing structure has a much lower G limit with the flaps deployed and at high weights and rolling in pitching during the dropping of the fire retardent pushed it beyond limits.
Why I ask is I read once that flap settings was one of the factors in the C-130A fire bomber accident , apparently the wing structure has a much lower G limit with the flaps deployed and at high weights and rolling in pitching during the dropping of the fire retardent pushed it beyond limits.
Instead, it blamed the crash on corrosion-aided fatigue cracking in the center box.
Apparently, there had been earlier cracking problems in "pre-E" model C-130 outer wings that had been fixed by adding stiffeners... which increased stress on the center box, which then got its own stiffeners. However, the stiffeners covered an area that was susceptible to corrosion, which could now not be seen in a visual inspection, leading to new cracking.
This was the specific cause cited by the NTSB for the center box failure.
-E model and later Hercs had a different alloy in both the outer panels and center box that was more resistant to cracking, as well as structure design changes to reduce areas of uneven stress loading.
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Flap Setting
Hi Greenknight
Yep, primary cause was corrosion and fatigue in H+P C-130 crash
I just found the paragraph on flap setting in the NTSB report , what is interesting was the pilot was correcting the pitch up of the C-130 when dropping the fire retardant when the accident occured.
My point is that the Java C-130 may have been in a similar flap configuration which in the case of a weakened wing structure (corrosion, fatigue) would make it weaker.
I'm not an aeronautical engineer so if I'm missing something or this is irrelevant I'm happy to be corrected.
Yep, primary cause was corrosion and fatigue in H+P C-130 crash
I just found the paragraph on flap setting in the NTSB report , what is interesting was the pilot was correcting the pitch up of the C-130 when dropping the fire retardant when the accident occured.
Airplane Operating Limitations
The FAA approved operating limitations for the airplane were based on two documents, one the original US Air Force flight manual, T.O. 1C-130A-1 (the Restricted Category certificate operating limitations required adherence to this document), and the supplemental operating limitations issued with the Supplemental Type Certificate for installation of the retardant tank and dispensing equipment. The original maximum-g load factor for the C-130A was +3.0 g/-1.0 g up to maximum level flight speed (Vh) at design gross weight (108,000 pounds); +2.0 g/-1.0 g up to maximum level flight speed (Vh) at maximum alternate gross weight (124,200 pounds). Operational limitations are defined in terms of gross weight and airspeed limits at 2.0g, 2.5g, and 3.0g missions in Figure 5-5 of T.O. 1C-130A-1. The maximum load factor on the FAA approved N130HP airplane flight manual is 2.5g based on the FAR Part 25 (25.337) and Car 4b. (4b.210) requirements. There are no structurally limiting factors for 2.5g. The maximum maneuver load factor regardless of cargo load, gross weight, or airspeed combination with any flap deployment was 2.0g; this is based upon the historical Military Specification (C-1803-E "Stress Analysis Criteria", dated June 17, 1949), which in turn defers to CAR 4b.212. Specifically, the flight manual cautions that "The maximum maneuver load factor, regardless of cargo load, with any flap extension is 2.0g." The event aircraft wreckage evidence indicated 50 percent flap extension. The flaps on a C-130A are considered secondary structure.
....
Safety Board Performance Study
The Safety Board conducted a performance study to in part determine the operating speed and load factor on the airplane both during the retardant drop run and at the time of wing separation. Video, photographic and other evidence was used during the study to reconstruct the performance of the vehicle. The evidence indicates that the aircraft was operating within placard speeds, but outside the maneuver load factor constraint of 2.0g with flaps deployed. The results of the performance analysis of the video and photographic evidence are consistent with the aircraft manufacturer’s residual strength analysis of the normal load factor required for wing separation. The estimated load factor at the time of the wing separation was 2.4 g, based on the combined effects of the pull up maneuver and retardant release. The presence of wind gusts or turbulence would require additional load factor corrections. The airplane was operating at 146 knots, just below it’s 150-knot limit airspeed.
At the request of the Safety Board, Lockheed performed a residual strength analysis to identify the vertical load factor that would have caused the center wing lower surface to fail based on the known fatigue damage documented in the metallurgical report. Lockheed concluded from the analysis that: “The center wing failed at a load that was approximately 30 percent of the design ultimate strength of the center wing and that the presence of fatigue cracks at multiple locations and in multiple structural elements reduced the residual strength to approximately 50 percent of design limit load and compromised the fail-safe capability of the structure.” The report opined that, “Failure was likely caused by a symmetric maneuver load exceeding 2.0g during the final drop of fire retardant.”
The C130 Walker Crash NTSB Report
The FAA approved operating limitations for the airplane were based on two documents, one the original US Air Force flight manual, T.O. 1C-130A-1 (the Restricted Category certificate operating limitations required adherence to this document), and the supplemental operating limitations issued with the Supplemental Type Certificate for installation of the retardant tank and dispensing equipment. The original maximum-g load factor for the C-130A was +3.0 g/-1.0 g up to maximum level flight speed (Vh) at design gross weight (108,000 pounds); +2.0 g/-1.0 g up to maximum level flight speed (Vh) at maximum alternate gross weight (124,200 pounds). Operational limitations are defined in terms of gross weight and airspeed limits at 2.0g, 2.5g, and 3.0g missions in Figure 5-5 of T.O. 1C-130A-1. The maximum load factor on the FAA approved N130HP airplane flight manual is 2.5g based on the FAR Part 25 (25.337) and Car 4b. (4b.210) requirements. There are no structurally limiting factors for 2.5g. The maximum maneuver load factor regardless of cargo load, gross weight, or airspeed combination with any flap deployment was 2.0g; this is based upon the historical Military Specification (C-1803-E "Stress Analysis Criteria", dated June 17, 1949), which in turn defers to CAR 4b.212. Specifically, the flight manual cautions that "The maximum maneuver load factor, regardless of cargo load, with any flap extension is 2.0g." The event aircraft wreckage evidence indicated 50 percent flap extension. The flaps on a C-130A are considered secondary structure.
....
Safety Board Performance Study
The Safety Board conducted a performance study to in part determine the operating speed and load factor on the airplane both during the retardant drop run and at the time of wing separation. Video, photographic and other evidence was used during the study to reconstruct the performance of the vehicle. The evidence indicates that the aircraft was operating within placard speeds, but outside the maneuver load factor constraint of 2.0g with flaps deployed. The results of the performance analysis of the video and photographic evidence are consistent with the aircraft manufacturer’s residual strength analysis of the normal load factor required for wing separation. The estimated load factor at the time of the wing separation was 2.4 g, based on the combined effects of the pull up maneuver and retardant release. The presence of wind gusts or turbulence would require additional load factor corrections. The airplane was operating at 146 knots, just below it’s 150-knot limit airspeed.
At the request of the Safety Board, Lockheed performed a residual strength analysis to identify the vertical load factor that would have caused the center wing lower surface to fail based on the known fatigue damage documented in the metallurgical report. Lockheed concluded from the analysis that: “The center wing failed at a load that was approximately 30 percent of the design ultimate strength of the center wing and that the presence of fatigue cracks at multiple locations and in multiple structural elements reduced the residual strength to approximately 50 percent of design limit load and compromised the fail-safe capability of the structure.” The report opined that, “Failure was likely caused by a symmetric maneuver load exceeding 2.0g during the final drop of fire retardant.”
The C130 Walker Crash NTSB Report
I'm not an aeronautical engineer so if I'm missing something or this is irrelevant I'm happy to be corrected.
Last edited by aseanaero; 21st May 2009 at 03:45.
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Takes time to get 100% Power
Among the myriad of drivel that SE-EMG posted, much of it unable to be deciphered, was a comment along the lines that it "takes a while to get to 100%". That is totally incorrect for the Allison in the C130. The engine is a constant speed engine/prop combination where the engine operates at between 98-102% RPM in all phases of flight and engine power changes are almost immediate, not unlike piston engine response to throttle movement. The only restriction of throttle movement was placarded to limit Throttle from Flight Idle to Max Take-off in not less than one second. Let's hope the real reason for this accident is made known in due course so that proper action can be taken to reduce the likelihood of another similar event.
Last edited by Old Fella; 21st May 2009 at 06:41. Reason: grammar
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Left or right wing
I suggest that this is the left wing showing impact damage up to the main spar with what seems to be the #2 motor.
Arend III.
Arend III.
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In "El Mundo" (Spain) read this morning an interview with two survivors:
1 described "an explosion and fire after impact".
The other reported "before impact we heard a deafening noise and then everybody was thrown about the cabin".
FWIW,
Rattler
1 described "an explosion and fire after impact".
The other reported "before impact we heard a deafening noise and then everybody was thrown about the cabin".
FWIW,
Rattler
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OK, aseanaero... it was a combination of the two. The corrosion-aided fatigue cracking was the cause of the failure, but exceeding G-limits with the flap setting was the "trigger event".
Corrosion/fatigue reduced strength to where the excessive G-loading with flaps deployed exceeded remaining strength.
If the G-load had been at or below 2.0 , or the flaps had not been deployed, the failure might still have happened - or might have not happened... but without the corrosion-aided fatigue cracking it certainly wouldn't have, as the actual stress was still well within designed limits.
I had not seen (or didn't remember) the comments about flap settings causing G-loading outside limits... thanks for posting them.
Corrosion/fatigue reduced strength to where the excessive G-loading with flaps deployed exceeded remaining strength.
If the G-load had been at or below 2.0 , or the flaps had not been deployed, the failure might still have happened - or might have not happened... but without the corrosion-aided fatigue cracking it certainly wouldn't have, as the actual stress was still well within designed limits.
I had not seen (or didn't remember) the comments about flap settings causing G-loading outside limits... thanks for posting them.
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I had not seen (or didn't remember) the comments about flap settings causing G-loading outside limits... thanks for posting them
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Channel News Asia is today quoting the Indonesian Defence Minister as saying that the defence budget granted was only one quarter of the amount requested by the Military and is blaming the crash on poor maintainence due to lack of cash !
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i would like to pass on my sincere condolences to those brave souls who were lost on the plane and to their loved ones left behind. RIP forever.
Finally, well done mods for getting rid of that ignorant swedish chap. Have some respect!
Finally, well done mods for getting rid of that ignorant swedish chap. Have some respect!
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Wing failure?
I must have missed something. I have not seen anything, other than conflicting witness statements, to indicate that wing separation occurred before impact. If the aircraft was on a stabilised approach with 50% flap, or even 100% flap, set there is no reason to suspect that excessive 'g' loading was applied. From what I have read it seems the aircraft touched down well short (5 nm was mentioned) of the airfield for a yet to be determined reason. Maybe it was a case of controlled flight into terrain.
Last edited by Old Fella; 24th May 2009 at 02:09.
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Hi Old Fella ,
I've been silent the last few days because as you say there are so many conflicting witness reports on what really happened.
The weather was fine at the time which makes this all the more confusing.
There's been an investigative team there and the wreck is being cleared from the rice paddies so there should be some preliminary announcement soon.
I've been silent the last few days because as you say there are so many conflicting witness reports on what really happened.
The weather was fine at the time which makes this all the more confusing.
There's been an investigative team there and the wreck is being cleared from the rice paddies so there should be some preliminary announcement soon.
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RIP to all who perished, and speedy recovery to the 15 who survived (in a report I heard, but stand to be corrected, and very sorry if that is wrong).
Sorry for thread drift, but earlier posts suggested that there were a large amount of passengers on board this aircraft. While looking up some facts on line, I came across a video, which mentioned a C130 leaving Vietnam in 1975 with 452 on board, of which 32 were in the cockpit. Does anyone have any proper information on that?
As I mention above, sorry for thread on this nasty crash, and if this post is deemed inappropriate I will delete it.
Sorry for thread drift, but earlier posts suggested that there were a large amount of passengers on board this aircraft. While looking up some facts on line, I came across a video, which mentioned a C130 leaving Vietnam in 1975 with 452 on board, of which 32 were in the cockpit. Does anyone have any proper information on that?
As I mention above, sorry for thread on this nasty crash, and if this post is deemed inappropriate I will delete it.
Ecce Homo! Loquitur...
A LONG TAKEOFF RUN AT TAN SON NHUT
On April 29, 1975, when the fall of Saigon was imminent. Tan Son Nhut Air Base was taking heavy fire, and its ramps and taxiways were littered with the burning carcasses of what had been the South Vietnamese Air Force. A VNAF officer, Tim Nguyen, saw a single Lockheed C-130A taxing out with people still streaming to climb on board the cargo ramp. He joined them, forcing his way on board.
At the end of the runway, the cargo door finally closed. The pilot, Major Phuong, pushed the power forward and the overweight Hercules slowly ran down the 9,000 foot runway, finally staggering off the ground at the end of the 1,000 foot overrun. The C-130 stayed in ground effect until it gained enough speed to begin a shallow climb.
The airplane was at least 20,200 pounds overweight, as it carried no fewer than 452 people, including thirty-three crowded into the flight deck. After a meandering flight of three and one-half hours, Phuong landed at U Tapao Royal Thai Air Base. When Nguyen got out, he looked at the C-130 and vowed that he would someday work for the company that built the airplane that saved his life. Today he does just that, at Lockheed Martin in Marietta, Georgia, where he is a specialist in defensive systems. The aircraft that carried him and 451 others to safety may now be found as the gate guardian at Little Rock Air Force Base, Arkansas.
On April 29, 1975, when the fall of Saigon was imminent. Tan Son Nhut Air Base was taking heavy fire, and its ramps and taxiways were littered with the burning carcasses of what had been the South Vietnamese Air Force. A VNAF officer, Tim Nguyen, saw a single Lockheed C-130A taxing out with people still streaming to climb on board the cargo ramp. He joined them, forcing his way on board.
At the end of the runway, the cargo door finally closed. The pilot, Major Phuong, pushed the power forward and the overweight Hercules slowly ran down the 9,000 foot runway, finally staggering off the ground at the end of the 1,000 foot overrun. The C-130 stayed in ground effect until it gained enough speed to begin a shallow climb.
The airplane was at least 20,200 pounds overweight, as it carried no fewer than 452 people, including thirty-three crowded into the flight deck. After a meandering flight of three and one-half hours, Phuong landed at U Tapao Royal Thai Air Base. When Nguyen got out, he looked at the C-130 and vowed that he would someday work for the company that built the airplane that saved his life. Today he does just that, at Lockheed Martin in Marietta, Georgia, where he is a specialist in defensive systems. The aircraft that carried him and 451 others to safety may now be found as the gate guardian at Little Rock Air Force Base, Arkansas.
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If my memory serves me correctly...that's NOT an 'A' model,
The most obvious difference in the 'A' was the three-bladed propellors!
'E' and on all had the four blades...
But then again, I didn't actually operate any Herc, but travelled as pax in them many times.
Cheers...FD...
The most obvious difference in the 'A' was the three-bladed propellors!
'E' and on all had the four blades...
But then again, I didn't actually operate any Herc, but travelled as pax in them many times.
Cheers...FD...
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AeroProducts {Propson 'A'
All RAAF C130A's used only Aeroproducts 3 blade 15' diameter props. Many USAF 'A' models were retrofitted with Hamilton-Standard four blade props of 13'6'' diameter.
