How not to fly when aerial firefighting
Join Date: Mar 2014
Location: Antarctica
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Not a pilot, but having flown on the flightdeck of C-130's many times in low level airdrop and tactical navigation scenarios (200 feet) including the provision of another pair of eyeballs for turning point identification, I am well aware of how deceptive rolling and hilly terrain can be. You're not flying instruments here, it's all eyes out looking but you may not always be looking at what you think your looking at. Add some turbulence and some significant g force in to the mix and momentary task distraction and concentration lapses can occur.
The video shows a few distinct points of interest. First, the speed brakes have been deployed as have the flaps. Accordingly, I presume the engines will spooled similar to a normal approach speed for this aircaft type. It seems a normal speed for the drop but the target area is tight to get into (and out of ). As I said , rolling terrain can be deceptive. How many have noticed the ridge they flew over to get to the target? Look at 00.05 on the video and see the aircraft shadow. Now your attention has been brought to it, this entry ridge stands out but how many never saw that ridge to start with? They crossed about 100 feet over that ridge on their approach down into the valley below. See how far below the ridge, the retardant falls after it is released. This just further amplifies the steep nature of the terrain and its deceptiveness. I'm not saying the crew didn't see that ridge, simply that the terrain is clearly deceptive making the exit strategy subject to being misread. In one account that accompanies one of the video's there is a suggestion (if it is from this incident) that the pilot admits he crossed the ridge below their normal ridge crossing altitude and that tunnel vision may have contributed to that. I suspect he's talking about the exit ridge, not the entry ridge. Another name for tunnel vision might be target fixation. Effectively, the PF is hunting to be in the pocket for a good drop.
Release time is about two seconds and it seems from other information related to demo drops of the BAE 146, that two seconds may only be about half the load. It also seems from the video that stop dump and pitch up occur very close together as though the crew have now realized they have reached the very edge of their escape envelope and must now exit. The first pitch up did not do it for them and at about 00.11 in the video they pitch up again, without which the outcome would have been CFIT. So the intriguing part for me is why the pilot flying didn't 'make an assertive enough pitch up to start with. Were the entry and exit ridges closer together than he thought? This could have been as a result of the terrain deceptiveness. Perhaps he expected the aircraft to perform better from spool up ie perhaps the crew planning was for a complete load release followed by exit with an expectation of an empty aircraft with corresponding performance. But with only half the load gone, the aircraft wasn't as agile in the limited exit profile and a secondary pitch up was necessary. Perhaps a downdraft coming over the exit ridge and rolling down towards the fire? Perhaps all of these factors combined to provide us all with a very dramatic ridge crossing.
But despite all that drama, I don't think he was scratching to make this. He knew from the first pitch up or perhaps as part of the approach to this drop that his ridge clearance was going to be possibly below SOP. This was evidenced by his first pitch up after the drop which was accompanied by a slight right wing drop to place him level with the ridge line in order to maximize wingtip clearance. So he knew then exit profile was going to be tight. But the second pitch up signaled an issue with clearance that didn't seem to be a concern at the first pitch up. Even then, it wasn't excessive or panicky and was almost just an adjustment to achieve a parallel path with the hillside, albeit a closer hillside than he had originally was planning! I would have thought that he could have and would have pitched up significantly more if he really thought it wasn't going to make it.
In summary, there is no doubt this drop was in a tight area and perhaps was not as well executed as perhaps it could have been had another approach path been selected. But then we can't see the line of fire so who knows. The pilot seems to have been comfortable with applying only the pitch up necessary to clear the exit ridge but had to adjust this perhaps due to terrain deception, lower than expected aircraft performance, down drafting or some combination of any or all of these factors. Whatever, the reason, it seems he had some spare maneuvering capability such that excessive pitch didn't appear necessary so long as one was comfortable with seeing lizards basking on rocks while your supposedly still flying!!
As an aside I recall in a multinational operation during the Gulf War where a C130 special ops crew (national identity not disclosed to protect the innocent) arrived in our Ops area to pick up some spare parts they had requested. We asked them what the parts were for and the flight engineer rather sheepishly indicated it was the underbelly VHF aerial to replace the one they lost recently during some level flying over sand dunes.Which kind of makes our firefighting crew pussy cats by comparison! While not in anyway condoning gung ho flying, I guess I am just saying some operations require a level of tolerance to risk and reduced margins of safety that cannot easily be measured against normal commercial operations.
The video shows a few distinct points of interest. First, the speed brakes have been deployed as have the flaps. Accordingly, I presume the engines will spooled similar to a normal approach speed for this aircaft type. It seems a normal speed for the drop but the target area is tight to get into (and out of ). As I said , rolling terrain can be deceptive. How many have noticed the ridge they flew over to get to the target? Look at 00.05 on the video and see the aircraft shadow. Now your attention has been brought to it, this entry ridge stands out but how many never saw that ridge to start with? They crossed about 100 feet over that ridge on their approach down into the valley below. See how far below the ridge, the retardant falls after it is released. This just further amplifies the steep nature of the terrain and its deceptiveness. I'm not saying the crew didn't see that ridge, simply that the terrain is clearly deceptive making the exit strategy subject to being misread. In one account that accompanies one of the video's there is a suggestion (if it is from this incident) that the pilot admits he crossed the ridge below their normal ridge crossing altitude and that tunnel vision may have contributed to that. I suspect he's talking about the exit ridge, not the entry ridge. Another name for tunnel vision might be target fixation. Effectively, the PF is hunting to be in the pocket for a good drop.
Release time is about two seconds and it seems from other information related to demo drops of the BAE 146, that two seconds may only be about half the load. It also seems from the video that stop dump and pitch up occur very close together as though the crew have now realized they have reached the very edge of their escape envelope and must now exit. The first pitch up did not do it for them and at about 00.11 in the video they pitch up again, without which the outcome would have been CFIT. So the intriguing part for me is why the pilot flying didn't 'make an assertive enough pitch up to start with. Were the entry and exit ridges closer together than he thought? This could have been as a result of the terrain deceptiveness. Perhaps he expected the aircraft to perform better from spool up ie perhaps the crew planning was for a complete load release followed by exit with an expectation of an empty aircraft with corresponding performance. But with only half the load gone, the aircraft wasn't as agile in the limited exit profile and a secondary pitch up was necessary. Perhaps a downdraft coming over the exit ridge and rolling down towards the fire? Perhaps all of these factors combined to provide us all with a very dramatic ridge crossing.
But despite all that drama, I don't think he was scratching to make this. He knew from the first pitch up or perhaps as part of the approach to this drop that his ridge clearance was going to be possibly below SOP. This was evidenced by his first pitch up after the drop which was accompanied by a slight right wing drop to place him level with the ridge line in order to maximize wingtip clearance. So he knew then exit profile was going to be tight. But the second pitch up signaled an issue with clearance that didn't seem to be a concern at the first pitch up. Even then, it wasn't excessive or panicky and was almost just an adjustment to achieve a parallel path with the hillside, albeit a closer hillside than he had originally was planning! I would have thought that he could have and would have pitched up significantly more if he really thought it wasn't going to make it.
In summary, there is no doubt this drop was in a tight area and perhaps was not as well executed as perhaps it could have been had another approach path been selected. But then we can't see the line of fire so who knows. The pilot seems to have been comfortable with applying only the pitch up necessary to clear the exit ridge but had to adjust this perhaps due to terrain deception, lower than expected aircraft performance, down drafting or some combination of any or all of these factors. Whatever, the reason, it seems he had some spare maneuvering capability such that excessive pitch didn't appear necessary so long as one was comfortable with seeing lizards basking on rocks while your supposedly still flying!!
As an aside I recall in a multinational operation during the Gulf War where a C130 special ops crew (national identity not disclosed to protect the innocent) arrived in our Ops area to pick up some spare parts they had requested. We asked them what the parts were for and the flight engineer rather sheepishly indicated it was the underbelly VHF aerial to replace the one they lost recently during some level flying over sand dunes.Which kind of makes our firefighting crew pussy cats by comparison! While not in anyway condoning gung ho flying, I guess I am just saying some operations require a level of tolerance to risk and reduced margins of safety that cannot easily be measured against normal commercial operations.
It seems a normal speed for the drop but the target area is tight to get into (and out of ). As I said, rolling terrain can be deceptive. How many have noticed the ridge they flew over to get to the target? Look at 00.05 on the video and see the aircraft shadow. Now your attention has been brought to it, this entry ridge stands out but how many never saw that ridge to start with? They crossed about 100 feet over that ridge on their approach down into the valley below. See how far below the ridge, the retardant falls after it is released. This just further amplifies the steep nature of the terrain and its deceptiveness. I'm not saying the crew didn't see that ridge, simply that the terrain is clearly deceptive making the exit strategy subject to being misread.
