Part 91 Instrument Approaches

[CoATP]

Is there a specific FAR that says Part 91 approaches can be initiated despite reported weather "to take a look", unlike 135/121 which require mins (vis) outside the FAF. Is it a default because it doesn't say? This is imporatant because it involves a bet!

 

[SPilot]

Here's my take on it:

Whatever is not explicitly forbidden by the FARs, is legal.

The only thing about IFR weather minimums in Part 91, has to do with alternate requirements in 91.169. Also, 91.175 only says you need the minimums on the approach plate, as well as having certain things in sight, and being able to make normal manouvers to land, at the time you wish to operate the aircraft below DH/MDA.

So in my interpretation, you can legally fly down to minimums even if the weather reports indicate that you wont see the runway. The only thing prohibited is to continue the approach below DH/MDA without determining that you have at least the approach plate minimums. For planning purposes however, it would be pretty lame to take off with reported weather way below the minimums...and Part 135 is another story.

 

[charter dog]

The basic requirements for landing under IFR are stipulated in 91.175. Note that the minimum flight visibility published on the IAP must exist at the time in order to continue descent below DH (DA) or MDA and beyond or below this point and must remain so all the way to touchdown. A missed approach is required if the flight visibility is determined to be less than the published minimum or if the required visual references are not in sight..

From FAR 1.1

Flight visibility means the average forward horizontal distance, from the cockpit of an aircraft in flight, at which prominent unlighted objects may be seen and identified by day and prominent lighted objects may be seen and identified by night.

These rules apply to all civil operations. In addition to these rules, operations conducted under 91 subpart K, 121, 125, 129 and 135 also require that additional conditions be met. These include that the officially reported wx be at or above published mins at the time the approach clearance is accepted and until on the final approach segment. Once inside the FAF, if a subsequent report indicates wx has fallen below the published minimums, the approach may be continued and a landing accomplished provided that the requirements of 91.175 are met. 135.225 explains this concept further. The operations or management (91K) specifications issued to the carrier are even more "specific" in this regard.

Whatever is not explicitly forbidden by the FARs, is legal.

In my view, this statement is true only to a limited degree. The concept is opposite to the operations specifications concept where nothing is authorized unless an OpSpec is issued. Under part 91, it is true only until an incident, accident or other occurance attracts the attention of the FAA. Recommended practices such as those contained in the AIM and applicable ACs then become the standard against which the appropriateness of your actions are measured. Review of NTSB appeals to FAA sanctions againt airmen reveals a mixed bag of results. In effect, following an occurance, you can be held to a standard higher than that provided for under part 91 regulations. 91.13 is the typical regulation cited when an occurance has transpired. Other regulations may or may not be cited, but this one is often tacked on!

Strictly speaking from a legality point of view, part 91 does not specifically prohibit beginning the approach when wx conditions are less than those published in the applicable IAP, while operations requiring OpSpecs do. So it is allowable. This is one example of a situation where the above quoted statement is true. Keep in mind that there may be many circumstances where this a poor defense against an accusation of "careless or wreckless operation".

Collect on the bet and fly safely!

Best,

 

[A Squared]

Originally Posted by SPilot
Whatever is not explicitly forbidden by the FARs, is legal.




In my view, this statement is true only to a limited degree. The concept is opposite to the operations specifications concept where nothing is authorized unless an OpSpec is issued.

I would say that it is generally true, to a very broad degree.

I agree that on the face of it, the ops specs appear to not fit this concept, but if you dig one layer deeper, you see that in fact they do. Remember that there is a regulation in part 119 which requires that ops specs be issued and another which "forbids" operating contrary to those ops specs, the regulations essentially fobid everything and the ops specs allow it.

I think that if you take the regulations as a whole, for every regulation which appears to permit something, it is only being permitted because it would be otherwise prohibited by another regulation.

So, yes, as a general rule, if something is not forbidden, it *is* legal, you just have to be careful the you are considering alle the regulations which might prohibit that action.

 

[Tonala2k]

To simplify it one step more. Nothing is illegal, or unauthorized until there is a rule to say so. (In any aspect in life. That's just how it is, and thankfully our forefathers knew it.)

The challenge of this bet falls on your buddy to prove him/herself right. You can't prove yourself right because you're asking where it is authorized. Again, it's just a fact of life that everything is authorized until a rule is made. So tell your buddy he/she has got seven days to prove or pay.