Accelerate/Stop Question

[flyinsocal]

I'd appreciate some comments on the following scenerio:

You are operating a King Air 90 under Part 91.

You are planning a flight to a runway 4200 feet long at an airport 3,500 MSL in the desert southwest - summertime temps.

Your aircraft performance section says the accelerate/stop distance is approximately 5000 feet.

Reducing weight doesn't help though a good headwind, if you could count on it, would. No other airport is convienantly located. Waiting for the temperature to drop is also not an option.

Your supervisor tells you that it is legal under Part 91 and this is "just part of flying in the real world" of corporate aviation.

What would you do?

My background:
Besides flight instructing, my background is primarily Part 121 where by regulation accelerate/stop is required. I am told that under part 91 taking off from a runway that is less than accelerate/stop is legal and is done frequently under Part 91. Corporate flying is new to me and I would like to hear the forums opinion.

Thank you for taking the time to respond.

 

[bafanguy]

Is the airplane manual FAA approved ? If so, I'd think if the performance chart says it's no-go... Airplane performance is a physics problem and the airplane doesn't know anything about Part 91.


Plus, wouldn't you want to see the section of Part 91 your boss is using to justify his telling you to go anyway ?

I suppose anything's possible but I'd be surprised if operating outside the airplane persformance parameters is legal under any part of the FAR's.

 

[magneticmd80]

acc stop

Interestingly enough I have had this very problem with my company. I was to fly a trip to
a 3000ft strip and my accelerate stop showed I needed 3400ft. This is in a be200. I said no
and did not go. If it is in your FAA approved aircraft flight manual it certainly is binding. If you
were to have an accident or incident you certainly would be accountable to explain why you went
knowing your manual showed you did not have enough runway. I was certainly willing to put
up with my company being inconvenienced, but they have no choice but to comply. I wouldn't go.

 

[flyinsocal]

Bafanguy

Good question.

FAA Performance section of the AFM does not list accelerate/stop. It does list takeoff distance required. However, the Beechcraft AFM lists accelerate/stop in "Supplemental Ops Data" section. Does that make it any less binding?

 

[cvsfly]

I've heard the arguement before. And still not sure. Lets compare a BE-58 and a BE-200. Both have charts for accel-stop & go. If you comply with Accel-stop do you also comply with the Accelerate-Go figures for? It's the difference between Part 23 vs 25 certified aircraft. Applicable Part 91 regs maybe 91.9, 91.13. Is the Performance section in the AFM also considered Limitations? Part 135 & 121 address aircraft performance in more detail.

 

[Singlecoil]

It is legal. I used to fly 402's in and out of 2300 foot strips under 135. Other carriers flew Navajo's and Beech 18's out of the same strip. It is certainly more risky than having a longer runway, but how is it any different than flying a single engine airplane? Lose one on takeoff, and you are going to run off the end. The hard part of flying a twin on a short runway is having the discipline to pull back the good one and roll into the weeds.

 

[501261]

No one ever said Legal meant safe! This is one of those cases, its certainly legal, but might not be the safest thing.

Incidentally, it would also be legal under 135, since the BE90 is a Small, nontransport (135.399) airplane, and one only needs to consider available runway.

 

[vetteracer]

I think the ACC/stop mins, per 135/121 apply to those aircraft over 12,500 lbs.

We operate King Air 200s out of 3000’ foot strips year round.

We were looking at getting a KA-350, but then we would have to adhere to the balanced field.

Mark

 

[Lead Sled]

Yeah, I’ve run into that mentality before. Here’s the problem with your scenario – under Part 91 (and probably 135 as well) no one is really going to care as long as everything goes well. But if there is an accident or incident and the FAA starts asking questions I’m sure that you will end up spending some “quality” one-on-one time with one of your friendly local feds. Among other things, the discussion would center around FAR 91.13 (Careless and Reckless Operation) and several other potential violations.

I don't mean to sound paranoid, but flying is nothing more that an exercise in risk management. You take acceptable risks and eliminate or at least minimize unacceptable ones. I only earn my money on those very infrequent days that I have to tell my boss "no". When the weather is good and when the equipment is operating correctly it doesn't take much of a pilot to do my job. It's when we have to deal with "difficult" weather, "belligerent" equipment, and/or "challenging" airports that I earn my money. In other words, I get paid to say "no". However, they expect me to have the skill and experience to only say "no" when it is the only safe option. Inexperienced pilots get into trouble when they say "no" and it wasn't necessary or when they don't say "no" when it was.

I love guys who advocate the philosophy that "if we loose an engine, we'll just close the other throttle and land straight ahead - just like if we were in a single." That's fine, and in many cases, it’s a viable option. However, you need to consider the effect that the heavier weight of most multiengine aircraft has on the survivability of an off field landing...

The FAA mandates that all certified single engine aircraft have a stalling speed no greater than 61 knots. (There are some exceptions to this rule, but it requires special equipment and certification.) There is no such requirement for multiengine aircraft. A few multiengine aircraft are light enough to come in with a stall speed less than 61 knots, but many designers will take the opportunity to take advantage of higher wing loadings to increase a light twin’s performance. What you end up with is aircraft with stall speeds significantly higher than the equivalent single engine airplane. Take the Beech A36 Bonanza and the Baron 58. Essentially, they are single and multiengine versions of the same airframe, with more or less comparable performance and capabilities. The Bonanza has a stall speed of 59 knots and the Baron, a stall speed of 73 knots.

So, what’s my point? If you double the stall speed, you multiply the kinetic energy four times. The survivability of a crash is a function of how quickly the kinetic energy is dissipated. What you end up with is a scenario where, in the event of an off field landing in a twin, you have nearly twice the kinetic energy to dissipate. If you’re lucky you’ll have a flat smooth surface, but throw in some rocks, trees, etc. and you quickly see why survivability is a big question. The same principle applies when you start trying to rationalize taking a plane like a KA-200 off the runway or trying to horse it into the air too early.

Personally, operating an airplane in the manner you described is “Faith-Based Aviation” – you’re betting your life (and the lives of your passengers) that an engine won’t quit during takeoff and for a certain period afterward. Personally, I believe that is an unacceptable risk.


I really don’t think that operating an aircraft with in its performance capabilities is limits their utility. (No more than saying that you shouldn’t fly single engine aircraft over weight is limiting, but there will always be those who are willing to ignore the W&B envelope and fill all of the seats, load the baggage, top off the tanks and go. To me, this is exactly the same principle.) We had a similar discussion a while back at FlightSafety. We occasionally have to deal with the same mentality in the corporate world – “The engine isn’t going to quit, why shouldn’t we load our passengers with enough fuel to make it to ‘where ever’ without having to make a fuel stop…” or (this is my personal favorite) “They build in a big enough safety margin that we can ignore the charts…”

So what if a lot of people operate their aircraft in a way that that leaves them “exposed”? Let’s assume that they have done it for hundreds of hours and have never had a problem – does this mean that the operation is safe or are they merely lucky? What do you think? You can fail to plan for your eventual engine failure and place your trust in the laws of probability. But remember, if you choose this path, the danger doesn’t go away, it merely lies in wait and when the inevitable occurs, the laws of physics (and gravity) take precedence.

As I said earlier, I believe that flying is essentially an exercise in “risk management” – you accept reasonable risks and try to eliminate or, at least, minimize the rest. Can you make flying totally risk free? Of course not, no more than you can make any other activity that we do risk free. However, if you go about it properly, flying is as about as benign an activity as you can possibly do. I have a framed photo of an old biplane hung up in the limbs of a tree. (You’ve probably seen the one I’m talking about; they’re in just about every pilot shop in the country.) The photo’s caption reads, “Aviation in itself is not inherently dangerous. But to an even greater degree than the sea, it is terribly unforgiving of any carelessness, incapacity or neglect.” I agree with that statement.

Remember, it’s all too easy to let bad operating practices creep into our day-to-day flying. Like the guy said when St. Peter met him at the Pearly Gates, “It never killed me before!” Oh well, I better get off my soap box.

Lead Sled

 

[Singlecoil]

A well-reasoned essay, Mr. Lead Sled. You make good points about the increase of kinetic energy with the higher abort speeds of twins. It is definitely a riskier operation to operate on shorter fields. We can argue the differences between Part 23 and 25 aircraft all day long but the fact remains that it is legal to operate some multi-engine aircraft on un-balanced fields. You can claim it is not safe and refuse to fly that flight, but you can also be fired with cause. In Alaska, this is a standard procedure. I'm not aware of any accident that has occurred during that five second period of vulnerabiltiy that we are describing here. In all candor, that is probably why it is still legal, but legal it is.

Your boss gives you a charter. There are three other carriers on the field. You could turn it down but you can expect to get some grief from your employer when the other carrier fires up and launches for this legal excercise. How safe is a 600 RVR takeoff in a single-pilot piston twin with an alternate an hour away over mountains? You are being paid to operate an aircraft within the regulations. ...I'm starting to sound like a management type here, but I'm staunchly pro-union. I'm not sure why I offer the "get the job done" opinion here, perhaps because I did that for 3000 hours and relished it. I have flown 121 for 4500 hours since then, but I don't see a huge difference between the two. ON PAPER, I can survive now, but most of the pax weigh a lot more than 180 pounds, the engines aren't brand new, and let's not even talk about the "25 pound" bags.