(Originally published at 11:24 a.m. MDT, August 3, 2014; revised August 4, 2014)
The issues that kept one of the DC-10s and all three of the MD-87 air tankers grounded for a while have been partially mitigated for the MD-87s, and totally fixed in the case of the DC-10.
DC-10
Tanker 910, a DC-10 operated by 10 Tanker Air Carrier, suffered some damage to a wing on July 19 as it was taxiing at the air tanker base at Moses Lake, Washington. While relocating in the loading pit area the aircraft struck a portable “air stair”, a structure that can be pushed up to the aircraft door. Two people on the ground were marshaling the DC-10 as it slowly moved, directing it where to go and supposedly watching for obstructions. Rick Hatton, President of 10 Tanker, told us that the air tanker was back in service on July 28.
Mr. Hatton said their second DC-10, Tanker 911, has been busy on fires. The third one being built now, Tanker 912, was test flown on August 2. It will enter service later this month, perhaps as early as August 11.
MD-87s
On June 27 Erickson Aero Tanker recalled the three MD-87s they were operating, tanker numbers 101, 103, and 105, “due to intermittent engine surges when dropping [retardant at] high coverage levels”, according to the U.S. Forest Service. The Oregonian later reported that retardant was being ingested into the engines. On June 30 Tanker 101 returned to service, but with restrictions. Tanker 105 should be in service the week of August 4, but with same restrictions.
We have confirmed that the air tanker is limited to no more than coverage level four, which is four gallons per 100 square feet — about half of the maximum coverage level for fully capable air tankers. Our understanding of the issue is that the MD-87s have two retardant openings on the belly. On most air tankers they are called “doors”, since they operate much like a door on a hinge, swinging down on some air tankers. But the MD-87 has two “spades”, which function like a stopper in a bathtub. The spade in the aircraft normally plugs the hole, but raises, in a constant-flow manner, to allow retardant to flow around it and exit the aircraft.
Tanker 101 is using just the left spade instead of both. That spade now has half a funnel at the leading edge to get the retardant moving backwards as it comes out. There is a report that a slight mist was still contacting the wing but it appears that retardant is no longer going into the engines. The leading edge slats make that small amount of retardant that touches the wing look worse than it is.
One of the MD-87 pilots is qualified for initial attack.
Phone calls to Erickson Aero Tanker requesting comments on this issue were not returned.
I’m sure they’ll work out the issues with the MD 87’s. And, they should be given ample opportunity to do so. New technology is seldom perfect. Safety of the crew is the biggest priority and retardant in the engines is not a good thing. Hope they get it sorted out soon!
The MD87 and DC10 have been doing a great job. There is rarely ever a scenario where a traditional LAT could get the job done but the jets couldn’t. In fact, the after drop climb capability of the BAe 146, MD87 or DC10 provide a larger margin for safety than the P2V.
The “after drop climb capability” of any airtanker, in theory, should not be considered as a safety enhancement. All bombing runs are made over level or descending terrain. If there are obstacles ahead of the airplane beyond the drop, there must exist a clear path to fly around them without the need to climb. This is an intractable rule borne from many historical accidents; no air attack nor airtanker pilot worth his or her salt will direct or accept a bombing run into rising terrain.
The ‘worst-case’ scenario must be considered: an airtanker loses thrust from an engine while low-level, coupled with an inability to jettison the load. This is unlikely to occur, but one must always retain the option to fly a heavily loaded airplane with one less engine towards safety.
On a separate note, some pilots prefer the instant response to thrust inputs of a turboprop engine as opposed to the lag experienced when applying thrust to a jet engine. Both engine types are managed well within acceptable margins of risk.
So if I can’t do my job I can’t go to work… So what is the point of having a half use airplane on the job? This problem should of been seen by the boys in Oregon just like everyone else had seen it coming. When is enough retartdant getting ingested into a engine enough? When both engines lose there hot section and we lose more great pilots? Pull the plug on this disasterous project before we lose human lives! Not sure why the forest service wants turbo fans anyways. They having nothing on a turbo prop other than they can fly faster which ok has it’s purposes but come on when it comes down to getting into the canyons and actually being useful on a fire turbo props are the only way to go.
If indeed the MD-87s are limited to no greater than a CL4, does that still meet the minimum specs contained within the Next Gen contract?