It is rare these days for a tanker to depart in IFR conditions with a load of retardant. We used to do it all the time and it is quite dangerous. After a few years, I refused to depart IFR with a load. The problem comes with the eventual emergency (engine failure,hydraulic failure, fire on board etc.) You have to pitch the load (or crash) and you can't see what you are dropping on. It could be a highway, a house or kids in a play ground. Then there is the very real problem of not being able to get back into the airport you just took off from because it is fogged in. Now you have to fly to your
alternate, IFR with an emergency on board. It's a terrible combination (G, former air tanker pilot).
So what are the options here? You are called to fly a fire, but your base is fogged in. Yes, you are an IFR rated pilot, as is your tanker. One option is to fly empty, under IFR if necessary, to another base with better weather and VFR conditions to load retardant and then fly to the fire under VFR.
Ok, going back to IFR for a moment, the book calls for what is know as a minimum altitude of 2,000 ft above the terrain. You can get down to 1,000 ft above the terrain and lower during an IFR-ILS approach. Consider the air tanker base in Missoula, Montana. Missoula is surrounded by mountains. One of the departure routes out of Missoula, Konna two departure, requires a 350 ft per nautical mile climb. G, who used to fly a P-2, tells me that translates to 1,050 ft per minute climb rate in a P-2 to meet the departure requirements. He goes on to explain what this means:
That's nothing for a modern jet airliner, but a tired old recip with an engine out would be hard pressed to make that kind of climb rate (1,050 per minute). The Missoula One Departure (another departure route out of Missoula) requires 400 ft per nautical mile or 1,200 ft per minute to safely get out of that valley without running into a mountain. Doing even an empty departure in IFR minimums out of a place like Missoula is asking for a whole heap of trouble if you lose an engine. You may not be able to meet the minimum climb gradient with an engine out. In 2000, flying out of Missoula in less than a mile visibility in smoke forced me to change my personal limits. I did it for a couple of weeks and then I decided this is nuts, so I refused. It's the whole idea of 'is this fire really worth injury or death to a civilian on the ground or losing a flight crew and tanker?'
Lives are not expendable.
IFR at fires?
Flying around the fire in smokey IFR is just a guess. There is no Air Traffic Control (ATC) that will even pretend to talk to you if you are that close to the ground. (G)
Remember the 2,000 foot minimum terrain separation that I was talking about earlier? I've covered retardant drops by tanker in other articles, and the tankers are flying at low altitudes when making the drop. Much lower than 2,000 feet above ground level. An inversion can trap smoke from a wildland fire under its lid. Of course smoke can be a problem over a fire without an inversion. A tanker flying in smokey IFR to drop retardant on a fire? Can you even drop the retardant where it needs to go without injuring someone on the ground? Can you drop the retardant without running yourself into the ground or clipping a tree with your wings? So sometimes smokey conditions at a fire can shut down an airshow.
Lives are not expendable.
Fog, remember fog? Fog over a fire might shut down an airshow but fog over a fire is good news for the firefighter on the ground because the moisture in the air aids in suppression efforts
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Note (added July 2012): I'd like to thank a couple of my tanker pilot friends whom I corresponded with as I was preparing the articles in this series for their time and help. Here is a complete list of articles in this series with hyperlinks:
1. Introduction (Jan 4)
2. VFR, I can see (Jan 6)
3. IFR, I can't see but I have instruments (Jan 8)
4. Fog (Jan 11)
5. Inversions (Jan 12)
6. Flying fires: VFR or IFR? (Jan 13)
7. Reflections (Jan 18)
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