Airborne With a Misloaded Aircraft
Thread Starter
Join Date: Nov 2004
Location: Here, there, and everywhere
Posts: 1,125
Likes: 0
Received 12 Likes
on
7 Posts
Airborne With a Misloaded Aircraft
A while back I started a thread about what you as airline pilots might do to prevent departing with a mis-loaded aircraft, as I thought there could be some good information passed around for our benefit. Perhaps, you know of an incident in your company that could provode useful information.
I was looking at an old accident thread recently and a couple of posts discussed an incident of a large airliner getting into the air after being very mis-loaded. There was information on what the crew did to help the situation and I thought that perhaps, there might be some other stories out there that could be beneficial to the rest of us. Things such as crew shifting cargo in flight, reduced flap for landing to minimize pitching moment, and what I believe to be maximizing trim range by using manual trim are quite interesting. Here is the post and reply......
Cargo Crash at Bagram - Page 2 - PPRuNe Forums
"In 2004 a Korean Airlines Cargo 747-400F in Oslo, Norway was loaded incorrectly and began its takeoff roll with a CG of 37.8% MAC. Thus being loaded 4.8% past the aft limit of 33% MAC.
The aircraft began to autorotate at 120 (KCAS) and thanks to the commander immediately suspecting a load error, the appropriate action was taken. However, nose attitude reached 19 degrees before sufficient downwards stab trim hab been applied.
Once in the air they contacted KAL operations through SATCOM and determined they could improve the situation by shifting a few pallets in the air. FO and relief FO proceded to shift a few pallets and the flight continued to Seoul.
Aircraft ended up landing with CG 7.2% aft of the limit.
When taking into consideration a possible rapid and extreme load shift far aft of the limit, it becomes evident that even with quick crew action the situation could become irrecoverable."
"... actually 58kts the nose wheel was off the ground. Aircraft was actually airborne at 120kts. On taxy to the runway the NLG WOG was intermittently air mode. The guys were the luckiest pilots on the planet.
FWIW, the Cm of the flaps is beneficial with an aft cg, MLG retraction is slightly beneficial. burning off the CWT may be wonderful for WBM structural considerations but guarantees the cg shifts aft. The arrival of that aircraft resulted in it departing the edge of the runway, however that is open to interpretation as the NLG was about 3' in the air, over the grass, but the MLG was on the concrete.
Had the AP disconnected in the cruise flight the aircraft probably would have been lost, as even with the AP engaged it exhibited longitudinal instability, and the elevator dP was rapidly cycling as was the elevator TE position in smooth air.
Not the first time, won't be the last time. Loading systems have many opportunities for variation from the expected process due to human ingenuity. A control problem close to the ground is a critical and generally untrained event. The opportunities for crosschecking are limited and need vigilance. I have bene caught out on the same type where 6.5T of cargo bound for the aft cargo comp went into the fwd comp, and we got to see the end of the runway up close and personal, took an extra 3000' of runway to get a rotate in, ended up with a part flap landing and full manual stab trim and still out of trim. Nowhere near as dangerous as the opposite case which appears to be a likely condition at Bagram."
I was looking at an old accident thread recently and a couple of posts discussed an incident of a large airliner getting into the air after being very mis-loaded. There was information on what the crew did to help the situation and I thought that perhaps, there might be some other stories out there that could be beneficial to the rest of us. Things such as crew shifting cargo in flight, reduced flap for landing to minimize pitching moment, and what I believe to be maximizing trim range by using manual trim are quite interesting. Here is the post and reply......
Cargo Crash at Bagram - Page 2 - PPRuNe Forums
"In 2004 a Korean Airlines Cargo 747-400F in Oslo, Norway was loaded incorrectly and began its takeoff roll with a CG of 37.8% MAC. Thus being loaded 4.8% past the aft limit of 33% MAC.
The aircraft began to autorotate at 120 (KCAS) and thanks to the commander immediately suspecting a load error, the appropriate action was taken. However, nose attitude reached 19 degrees before sufficient downwards stab trim hab been applied.
Once in the air they contacted KAL operations through SATCOM and determined they could improve the situation by shifting a few pallets in the air. FO and relief FO proceded to shift a few pallets and the flight continued to Seoul.
Aircraft ended up landing with CG 7.2% aft of the limit.
When taking into consideration a possible rapid and extreme load shift far aft of the limit, it becomes evident that even with quick crew action the situation could become irrecoverable."
"... actually 58kts the nose wheel was off the ground. Aircraft was actually airborne at 120kts. On taxy to the runway the NLG WOG was intermittently air mode. The guys were the luckiest pilots on the planet.
FWIW, the Cm of the flaps is beneficial with an aft cg, MLG retraction is slightly beneficial. burning off the CWT may be wonderful for WBM structural considerations but guarantees the cg shifts aft. The arrival of that aircraft resulted in it departing the edge of the runway, however that is open to interpretation as the NLG was about 3' in the air, over the grass, but the MLG was on the concrete.
Had the AP disconnected in the cruise flight the aircraft probably would have been lost, as even with the AP engaged it exhibited longitudinal instability, and the elevator dP was rapidly cycling as was the elevator TE position in smooth air.
Not the first time, won't be the last time. Loading systems have many opportunities for variation from the expected process due to human ingenuity. A control problem close to the ground is a critical and generally untrained event. The opportunities for crosschecking are limited and need vigilance. I have bene caught out on the same type where 6.5T of cargo bound for the aft cargo comp went into the fwd comp, and we got to see the end of the runway up close and personal, took an extra 3000' of runway to get a rotate in, ended up with a part flap landing and full manual stab trim and still out of trim. Nowhere near as dangerous as the opposite case which appears to be a likely condition at Bagram."
A while back I started a thread about what you as airline pilots might do to prevent departing with a mis-loaded aircraft, as I thought there could be some good information passed around for our benefit. Perhaps, you know of an incident in your company that could provode useful information.
I was looking at an old accident thread recently and a couple of posts discussed an incident of a large airliner getting into the air after being very mis-loaded. There was information on what the crew did to help the situation and I thought that perhaps, there might be some other stories out there that could be beneficial to the rest of us. Things such as crew shifting cargo in flight, reduced flap for landing to minimize pitching moment, and what I believe to be maximizing trim range by using manual trim are quite interesting. Here is the post and reply......
Cargo Crash at Bagram - Page 2 - PPRuNe Forums
"In 2004 a Korean Airlines Cargo 747-400F in Oslo, Norway was loaded incorrectly and began its takeoff roll with a CG of 37.8% MAC. Thus being loaded 4.8% past the aft limit of 33% MAC.
Once in the air they contacted KAL operations through SATCOM and determined they could improve the situation by shifting a few pallets in the air. FO and relief FO proceded to shift a few pallets and the flight continued to Seoul.
Aircraft ended up landing with CG 7.2% aft of the limit.
When taking into consideration a possible rapid and extreme load shift far aft of the limit, it becomes evident that even with quick crew action the situation could become irrecoverable."
"
I was looking at an old accident thread recently and a couple of posts discussed an incident of a large airliner getting into the air after being very mis-loaded. There was information on what the crew did to help the situation and I thought that perhaps, there might be some other stories out there that could be beneficial to the rest of us. Things such as crew shifting cargo in flight, reduced flap for landing to minimize pitching moment, and what I believe to be maximizing trim range by using manual trim are quite interesting. Here is the post and reply......
Cargo Crash at Bagram - Page 2 - PPRuNe Forums
"In 2004 a Korean Airlines Cargo 747-400F in Oslo, Norway was loaded incorrectly and began its takeoff roll with a CG of 37.8% MAC. Thus being loaded 4.8% past the aft limit of 33% MAC.
Once in the air they contacted KAL operations through SATCOM and determined they could improve the situation by shifting a few pallets in the air. FO and relief FO proceded to shift a few pallets and the flight continued to Seoul.
Aircraft ended up landing with CG 7.2% aft of the limit.
When taking into consideration a possible rapid and extreme load shift far aft of the limit, it becomes evident that even with quick crew action the situation could become irrecoverable."
"
So, I ended up doing a simple deformable model of the plane to slow what had happened, as the boys had just under 9 degrees bank on and didn't touch a pod. The bank resulted in an increase in tail clearance at the point that the WOW transitioned. Wasn't the last time deformable structure was needed to get heads pointed in the right direction... One other notable one was a #2 and #3 pod strike on a landing that didn't reach the roll angles of the FCTM geometry limit guidance material. Well, if you whack mother earth hard enough, the blender at the end of a lever tends to torque the wing and you gonna get a curious rash on occasions much further forward on the nacelle than you would expect from a simple roll/pitch geometry.
Anyway, back to the story...
Yes, the 2 trusty FOs did try to move cargo, and no, it didn't get much done. by memory a very light pallet just aft of the wing root center chord got moved with great difficulty, and that was aided as a number of the locks hadn't been put in place. the rest of the stuff was left where it started. The load was spectacular. there was nothing in the front half of the main deck cargo area, it was a ballroom upfront and everything down back, and no one thought that was odd.
The call to OCC wasn't immediate, I was woken up to give input, and they had already burnt off the CWT which was a shame. cuz, the cg on landing was further back than it had been on the T/O. The CG was far enough back on the taxi for takeoff that the NLG WOW was intermittent just in the taxi, and the plane wasn't responding well to the tiller input.
Did suggest they fly a nice stable final, as a G/A was going to be worthy of a director's chair & popcorn. It landed on 33R, was going for the cargo apron which is a right turn off the strip, but ended up with it's nose wheels dangling over the left side of the runway edge, over the grass. the nose tyres never touched grass,
Manual speed brake and no more than idle reverse had been suggested, can't recall if they actually followed that suggestion. The data rate on the elevator channel was not bad, and it showed oscillation of the elevator in the cruise on autopilot, which supported my contention that the boys had been rather lucky. The suggestion to reduce altitude to improve damping had been made, and that wasn't done IIRC.
It was memorable for the nose starting to rise at 56kias, and passing 9 degrees at 100kts without input by the crew.
The loading error arose as the GHA (pretty good normally)had used the envelope limit not the APS index to start the load plan. They sure needed some big hammer blows to get it to accept the load. Can't recall right now, but I think the load sheet ended up being manual, (I think the screen printed loadsheet was of an A320-200 out of Paris.... or it could have been this one... some of this stuff is a bit hazy now, and in all honesty, can't even say this was the most spectacular whoopsie that week. Those were pretty interesting days, and the effort did seem to get some improvements. There were a lot of really good people there, the ex army and navy chopper guys were a hoot to fly with, they knew where they were in space n' time; the F-4 guys were not too bad, the F-5A's some were good, the F-16 guys were children of the magenta line.
There was the one F/O that totalled 2 A300-605s in a week... one on the final leg of his command checkout, and a week later as a newly minted captain on the 4th leg in command. That actually was funny in bits, while crying it was hard not to see the funny side. On taxi in, the APU wouldn't start, as it was mainly still on the runway following the G/A attempted by pitching full up while still in reverse thrust. that got resolved by stowing the T/Rs and continuing the tail drag down the runway emulating a Vmu test, without the bit of mahogany on the tail.
Still love flying back there; best engineers in the world, bar none.
IMHO
It should be noted that the investigation of the Bagram crash indicated that the load shift - by itself - didn't make the aircraft unflyable. There is apparently considerable margin in the CG limits if the pilots are on the ball. Rather, the reason the Bagram 747 became uncontrollable was that when the MRAP broke loose, it smashed through the aft pressure bulkhead taking out several hydraulic systems. It was loss of those hydraulic systems that made the aircraft uncontrollable.
Moderator
Being a bit of a jaundiced old dinosaur, I lament the disappearance of some of the valuable checks and balances we had in days of yore, especially in the freight game.
Things such as -
(a) the flightcrew checked the can tags prior to loading as the trucks came up to the aircraft - weight and order - for subsequent checking against the load sheet data
(b) the shed ran the calculations using a manual trimsheet. The flightcrew then ran a check on the trimsheet against the can load data previously obtained (to check weight and order) with one crew member running a CG check using a circular, prayer-wheel style of trimsheet. This could be done as quickly as the captain read out the trimsheet weight entries.
(c) as the flightcrew generally couldn't get access to double check the locks, the loaders were rigorously trained to be highly aware of lock integrity, especially in the case of empty bays.
Didn't mean that there were never any mistakes made, but the risk was kept pretty low. As I recall, the only significant embarrassment was on a wet night departure - water had got into the innards through the freight door and there was a major electrical failure during rotation. Fortunately, the crew kept their cool and all was well ... if a little sweaty.
From a flight standards and training point of view, perhaps an early rotation or other indication of significant misloading (tiller responses ?) should be sufficient reason to reject the takeoff/taxi and return to the shed for a check on the load.
I can recall one case where we had an interference problem with the weighbridge and all the weights were wrong. The crew rejected the load (can't recall now whether on taxi or takeoff) and took the aircraft back to the shed, at which stage the weighbridge problem was detected.
One fleet had an on-board oleo weight and CG check system. Always gave wrong numbers but they were consistently and predictably wrong so the check on taxi was useful. As I recall, there was at least one occasion during my time on that fleet where a significant misload was picked up on the taxi and confirmed when the aircraft returned to the shed for a load recheck.
Things such as -
(a) the flightcrew checked the can tags prior to loading as the trucks came up to the aircraft - weight and order - for subsequent checking against the load sheet data
(b) the shed ran the calculations using a manual trimsheet. The flightcrew then ran a check on the trimsheet against the can load data previously obtained (to check weight and order) with one crew member running a CG check using a circular, prayer-wheel style of trimsheet. This could be done as quickly as the captain read out the trimsheet weight entries.
(c) as the flightcrew generally couldn't get access to double check the locks, the loaders were rigorously trained to be highly aware of lock integrity, especially in the case of empty bays.
Didn't mean that there were never any mistakes made, but the risk was kept pretty low. As I recall, the only significant embarrassment was on a wet night departure - water had got into the innards through the freight door and there was a major electrical failure during rotation. Fortunately, the crew kept their cool and all was well ... if a little sweaty.
From a flight standards and training point of view, perhaps an early rotation or other indication of significant misloading (tiller responses ?) should be sufficient reason to reject the takeoff/taxi and return to the shed for a check on the load.
I can recall one case where we had an interference problem with the weighbridge and all the weights were wrong. The crew rejected the load (can't recall now whether on taxi or takeoff) and took the aircraft back to the shed, at which stage the weighbridge problem was detected.
One fleet had an on-board oleo weight and CG check system. Always gave wrong numbers but they were consistently and predictably wrong so the check on taxi was useful. As I recall, there was at least one occasion during my time on that fleet where a significant misload was picked up on the taxi and confirmed when the aircraft returned to the shed for a load recheck.
It should be noted that the investigation of the Bagram crash indicated that the load shift - by itself - didn't make the aircraft unflyable. There is apparently considerable margin in the CG limits if the pilots are on the ball. Rather, the reason the Bagram 747 became uncontrollable was that when the MRAP broke loose, it smashed through the aft pressure bulkhead taking out several hydraulic systems. It was loss of those hydraulic systems that made the aircraft uncontrollable.
