approach mins

[Donsa320]

I have no dog in the weather minimums fight for 135 operations but let me ask this then. Since MDA's are published based on the Terps required obstacle clearance (ROC) and THEN rounded up or down to the nearest 20ft value do you then round up to the next reportable ceiling in hundreds of feet? If so, then a 320 ft MDA would require a 400 ft ceilng putting us back to the old ANC days where minimums WERE based on ceiling. That is called OCL...Obstacle Clearance Limits rules, still used in some parts of the world. That, however, was not the intent when Terps was established as the law of the land. Visibility value was supposed to be the only requirement as far as weather minimums were concerned.

I was on the ALPA Terps committee for many years and that is what the intent was. If some how the rules for 135 ops have departed from that then I guess a good court challenge is the only solution.
~DC

 

[igneousy2]

If ceiling was required under the regulations it wouldn't make sense...

91 -- no weather needed
135 -- ceiling and visibility
121 -- just visibility

This goes against the general principal that 121 operators have more strict rules than 135 operators. Not that it matters much anymore, however I belive that the original writers did not even intend VISIBILITY to be limiting to 135 operators. As another poster has previously pointed out, the visibility value is the prevailing (>50%) at a specific point at the airport (generally the tower). This point may be miles away from the runway in use. I believe they intended 135 operators to be able to use both values in concert with neither being a solid limitation for starting the approach.

Unfortunately, everyone in charge of making, interpreting and enforcing the rules rarely have any need or experience with living with the rules.

The notion that Ceiling is controling to start an approach is absurd. Even a report of overcast still allows for 10% of the sky to be cloud free. If that 10% is over the right spot it could at least allow you to see the approach lights and continue.

I think it was intended to be...

91 -- no weather needed
135 -- all available weather data indicates a sucessful approach would be possible considering all factors. i.e. runway in use, circle vs straight in, terrain/obstructions, individual aircraft performance and instrumentation.
121 -- prevailing visibility at or above approach minimums.

Too bad it's left up to a bunch of lawyers & inspectors with little or no aviation experience.

Later

 

[fly4free]

in my opinion

This goes against the general principal that 121 operators have more strict rules than 135 operators.

I'm not sure that 121 is generally more strict...I think they have more leanient dutie rules (although much more clearly defined) etc. allowing visibility only for 121 approach criteria would be less restrictive and this would be allowed because 121 has more training, more professional pilots (laugh), and more FAA oversight.

requiring the 135 pilot to have more criteria for the approach makes sense to me...wide variety of aircraft, less standardization, more diverse pilot work force.

IMO it makes sense for 135 to be more restrictive, not less.

E

 

[blimpguy]

A Referenced Answer

Good day to all. I've been reading these forums for a while, but this is my first post.

I believe I have the correct answer to the "weather minimums" question in the reference below. This is the second paragraph on page 5-5 of the FAA's new Instrument Procedures Handbook (2004), FAA-H-8261-1. I qouted the entire paragraph for context, but you can skip down to the all-capitalized sentence. It seems to be very black and white and is very recent. I'd toss a copy of that handbook to my attorney at the hearing.

PART 135 OPERATORS
"Another very important difference between Part 91 and Part 135 operations is the Part 135 requirement for airports of intedned landing to meet specific weather criteria once the flight has been initiated. For Part 135, not only is the weather required to be forecast at or above IFR landing minimums for planning a departure, but it also must be above minimums for initiation of an instrument approach and, once the approach is initiated, to begin the final approach segment of an approach. Part 135.225 states that pilots may not begin an instrument approach of the final approach segment of an IAP to an airport unless the latest weather report indicates that the weather conditions are at or above the authorized IFR landing minimums for that porcedure. This means that Part 135 operators are restricted from passing the initial approach fix (IAF) and the final approach fix (FAF) if the weather is reported below minimums. Part 135.225 also provides relief from this rule if the aircraft has already passed the FAF when the weather report is received. IT SHOULD BE NOTED THAT THE CONTROLLING FACTOR FOR DETERMINING WHETHER OR NOT THE AIRCRAFT CAN PROCEED BEYOND THE IAF OR FAF IS REPORTED VISIBILITY. The runway visibility value (RVV), reported in statute miles (SM), takes precedence over prevailing visibility. There is no required timeframe for receiving current weather prior to initiating the approach."


Well, I hope that clears things up. Feel free to lambast me if I missed the point.

blimpguy
ATP AMEL
ASEL, ASES
Heli
Airship

 

[vnyflyer]

This is how it goes down. The Faa interpretation of the regs say that you must CONSIDER the ceiling, but visibility is controlling. Such as if the weather was ovc 100-1/2, and the minimums were 200-1/2 you cannot legally shoot the approach. However if it was broken at 100 feet, then you could. Because you have considered the ceiling and there is a decent chance of seeing the runway. Also if you decide to shoot it with the overcast at 100 feet, then you could possibly face violation of Part 91.13, careless or reckless operation of aircraft. Thats never a good idea. Hope this all made sense.
Jake

 

[Donsa320]

This is how it goes down. The Faa interpretation of the regs say that you must CONSIDER the ceiling, but visibility is controlling. Such as if the weather was ovc 100-1/2, and the minimums were 200-1/2 you cannot legally shoot the approach. However if it was broken at 100 feet, then you could. Because you have considered the ceiling and there is a decent chance of seeing the runway. Also if you decide to shoot it with the overcast at 100 feet, then you could possibly face violation of Part 91.13, careless or reckless operation of aircraft. Thats never a good idea. Hope this all made sense.
Jake

There is NO such interpretation or consideration in 121 operations. Visibility is controlling. If you have some problem with someone in 135 operations making such a statement, that is your problem.

One wonders where this stuff comes from. We have enough regulations without anyone making new ones up.

~DC

 

[vnyflyer]

Sure, I'll explain your FAA letter of interpretation.

"FAR 135.225(a) and 135.225(a)(2) forbid a Part 135 pilot from beginning an instrument approach unless reported weather conditions at the destination airport are at or above the authorized IFR landing minimums for that airport."

I beleive this is what we have been saying in the begining - the fact that the "authorized IFR landing minimums for that airport", are indeed the visibility minimums published on the plate.

"So, even though ceiling is not a criterion on the approach plates, it must be considered by the pilot in his decision to initiate the approach, and in deciding whether the reported ceiling is above or below the decision height or minimum descent altitude for the approach".

Your source even states that "[the] ceiling is not a criterion on the approach plates". He is just saying that the PIC should consider the ceiling in his decision to initiate the approach. Obviously, prudence would demand that caution be excercised, while not forbiden, to shooting an approach to a runway with adequete visibility but a measure ceiling 200 feet below the published MDA.

-777JP

that looks like an interpretation to me. maybe you should spend some more time on reading the 135 Regs. i really hate to argue with somebody with 32,000 hours

 

[Donsa320]

that looks like an interpretation to me. maybe you should spend some more time on reading the 135 Regs. i really hate to argue with somebody with 32,000 hours

And your point is?

~DC

 

[greygoose]

Such as if the weather was ovc 100-1/2, and the minimums were 200-1/2 you cannot legally shoot the approach. However if it was broken at 100 feet, then you could.

I have shot many apps down to minimums, 100ovc and 200ovc with rvr controlling at 1800RVR. Makes no difference if it is ovc or broken if you can see the runway, every day is different.
Just like many other topics on the Far's is all down to interpretations. The company that I fly for has a FSDO go over our procedures all the time. Last I was taught by my company was visibility is controlling. Flying into another district doesn't mean they will agree. For the majority of Inspectors you ask that grill 135 pilots, they will agree that visibility is controlling. The biggest thing the FAA publishes DH and MDA is so you don't have idiots continuing too low when they don't see the airport.

 

[gern_blanston]

...if the weather was ovc 100-1/2, and the minimums were 200-1/2 you cannot legally shoot the approach. However if it was broken at 100 feet, then you could. Because you have considered the ceiling and there is a decent chance of seeing the runway. Also if you decide to shoot it with the overcast at 100 feet, then you could possibly face violation of Part 91.13, careless or reckless operation of aircraft. Thats never a good idea. Hope this all made sense.
Jake

Sorry. No dice. Part 91, a pilot can shoot the approach and take a look for the runway at the DH/MAP. Doesn't matter what the ceiling/vis are. Screwing up a missed approach and crashing is what's illegal. Part 135, the pilot can shoot the approach if he has whatever visibility mins apply to the operation (charted mins, Ops Specs, etc.) prior to reaching the FAF. I'd be curious if anyone could find a 135 POI that says otherwise.
As for 'considering' the ceiling: DUH!

 

[b82rez]

This is how it goes down. The Faa interpretation of the regs say that you must CONSIDER the ceiling, but visibility is controlling. Such as if the weather was ovc 100-1/2, and the minimums were 200-1/2 you cannot legally shoot the approach. However if it was broken at 100 feet, then you could. Because you have considered the ceiling and there is a decent chance of seeing the runway. Also if you decide to shoot it with the overcast at 100 feet, then you could possibly face violation of Part 91.13, careless or reckless operation of aircraft. Thats never a good idea. Hope this all made sense.
Jake

At least these flamers are getting a little better at playing the part. This one was actually funny....keep arguing with him guys.

 

[AIR2MUD]

Oh, yeah, those guys. The military. (in peacetime in U.S. airspace)
"...What!?..the anti-skid material on the door step is gettin' worn down??...CANCEL!! Write it up!!...Let's hit the club!"

Dude, you got it all wrong.

If that anti-skid stuff was worn, and it was a Friday, this is what I'd do: go fly my sortie, get to shoot the gun, drop some blue death for beers, 'forget' to turn the pod to STBY just so something was broke when I got back (have to keep those maintainers busy!), p!$$ on the seat while attempting to use a piddle pack (blame it on water bottle explosion in the MOA), land, dearm, taxi in, laugh as the crew chief dances like his nads are on fire while directing me in, and on the way down the ladder fake a fall and blame it on the crew chief for not replacing worn anti-skid stuff, thereby ensuring he owes me a case of beer for my efforts.

THEN hit the club, etc.

 

[Prof. ATP]

Four pages and nobody has got it right. Our Op Specs say that RVR is controlling, or visibility if no RVR is reported. The Op Specs tell you what the Administrator has authorized, not the FARs.

Given that, I have many times refused to launch when the reports and forecasts (or any combination thereof) indicated that I would be wasting my time and my customer's money by shooting an ILS into 100' ceiling, even with the required visibility. It's legal, but stupid.

 

[b82rez]

Four pages and nobody has got it right. Our Op Specs say that RVR is controlling, or visibility if no RVR is reported. The Op Specs tell you what the Administrator has authorized, not the FARs.

Given that, I have many times refused to launch when the reports and forecasts (or any combination thereof) indicated that I would be wasting my time and my customer's money by shooting an ILS into 100' ceiling, even with the required visibility. It's legal, but stupid.

Try again. If the FARs are more restrictive than your op specs, the FARs would take precedance.

And shooting an ILS to 100 and 1/2 is both legal and safe.

 

[LNKav8R]

REMEMBER how big is the little light that looks for ceiling??? About as big around as a pencil? So once you start the approach if you see the field you land, if not you don't. If you have the visiblity then you can see the field if the ceiling is ok. You could have clouds that feasibly have bigger/smaller clouds moving up and down and making the ceiling change. Also remember that ATIS is only scripted 1 time per hour at most places. So who actually makes the decision if the ceiling has come up enough in the last 5 minutes to continue the approach. Also the ceiling could have gone down in the last 5 minutes, as long as you've got the vis, you can shoot the approach. As I understand it the ceiling is a guideline for how low you can really go without seeing anything. So if the ceiling is showing 200' below the MDA then the chances of seeing the field are slim and you might have to use an alternate. I know I've rambled, sorry...