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Posted
1 hour ago, jetdriven said:

You add 50’ to an MDA when using vertical guidance on a approach without a DA. But adding 50’ to an MDA is limiting you artificially to somewhat early go around from an otherwise normal approach. 
there’s a common misconception that descent below DA is somehow wrong or unsafe.      I’ve only done it in the simulator but it’s also in the book. A 747 going missed from a 50’ RA will skip off the runway. Unsafe? Dangerous?  Or designed in? 

No, I add 50’ so my minimum alert annunciates BEFORE i hit the minimum. 
I’ve only had a handful of approaches where I was even close to minimums, and have never had to get below my additional 50’ threshold. 
Im pretty sure it has to do with how I plan. 
I would not say it’s what everyone should do, or that it’s better. 
It’s just my prerogative.  I don’t have to get anywhere bad enough to break my minimums. 
To each their own. 

  • Like 1
Posted
16 hours ago, Rusty Pilot said:

Becca great point about pilot not referencing his personnel minimums.  I am a new instrument pilot and have my personnel minimums set high for comfort and safety.

Having personal minimums is a good thing.  For purposes of training and proficiency, us instrument pilots should be able to hand fly a precision approach to minimums every day of the week and twice on Tuesday.  
 

The sequence here somewhat reminds me of aspects of this:

 

https://www.aopa.org/training-and-safety/online-learning/accident-case-studies/final-approach

 

 

  • Like 3
Posted (edited)

It's ok to go under DA duing missed if you have official & protected vertical guidance: ILS, LPV, L/VNAV...no need to add +50ft to DA 

It's not OK go under non-procesion MDA: LOC, LNAV, CTL...even with advisory +V vertical guidance or CDFA, so most poeple add +50ft to MDA

What one should not do is land after they decided to go missed near minimums: you often see runway during missed as the aircraft dips under "3D DA" and gets closed to threshold...not ideal for landing with bouncy doughnuts, you see the runway better on 2nd time :D

Edited by Ibra
  • Like 2
Posted
9 hours ago, jetdriven said:

You add 50’ to an MDA when using vertical guidance on a approach without a DA. But adding 50’ to an MDA is limiting you artificially to somewhat early go around from an otherwise normal approach. 
there’s a common misconception that descent below DA is somehow wrong or unsafe.      I’ve only done it in the simulator but it’s also in the book. A 747 going missed from a 50’ RA will skip off the runway. Unsafe? Dangerous?  Or designed in? 

Sims are great for this.

When I was in UPT we would do "solo" sim rides.  It meant two students without an instructor.  If the other student was flying and messed up the approach, but I could see the runway, I would try to land.  Did I do it every time?  NO.  But I found my limits to try it if the choice was land or eject.

Posted
9 hours ago, Schllc said:

I don’t want to wade into the argument of the legality, I just try to stay so far on the legal side that there isn’t a debate. 

its not an argument about legality, it was about leaving off the paragraph leading up to the three bullets, which are crucial to understanding.

Posted

14 CFR § 91.175

(c) Operation below DA/DH or MDA. Except as provided in § 91.176 of this chapter, where a DA/DH or MDA is applicable, no pilot may operate an aircraft, except a military aircraft of the United States, below the authorized MDA or continue an approach below the authorized DA/DH unless:

(1) The aircraft is continuously in a position from which a descent to a landing on the intended runway can be made at a normal rate of descent using normal maneuvers, and for operations conducted under part 121 or part 135 unless that descent rate will allow touchdown to occur within the touchdown zone of the runway of intended landing;

(2) The flight visibility is not less than the visibility prescribed in the standard instrument approach being used; and

(3) Except for a Category II or Category III approach where any necessary visual reference requirements are specified by the Administrator, at least one of the following visual references for the intended runway is distinctly visible and identifiable to the pilot:

 

Busting a MDA without the three requirements is ilegal, I think that's quite clear.

Now, regarding DA/DH, I have my doubts also, the reg says: "...or continue an approach below the authorized DA/DH unless..."

So, I can interpret that I can descend down to DH, at that point I must make the call wether to land or not. If the three requirements are not met I must chose not to land. So I abort the approach and go missed, at the DH. Again, I'm taking the decision and interrupting (i.e. no continuing) the approach at the DA/DH, not lower than that. But as I set the power, arrest the descend and start to climb I will go below DA/DH. Is that ilegal? From the reg perpsective, doesn't sound like it is.

Now, is it smart? Probably not.

Anyway, I think the guy that originated this thread (meaning not the OP but the guy that tangled his Mooney in the power lines) was not in this technicalities, but doing thing much worse than this.

If you will, the reg starts by saying:

(b) Authorized DA/DH or MDA. For the purpose of this section, when the approach procedure being used provides for and requires the use of a DA/DH or MDA, the authorized DA/DH or MDA is the highest of the following:

(1) The DA/DH or MDA prescribed by the approach procedure.

(2) The DA/DH or MDA prescribed for the pilot in command.

(3) The DA/DH or MDA appropriate for the aircraft equipment available and used during the approach.

I would argue that the pilot in command was proficient enough to even start the approach, as he was not familiar with the waypoints of the approach (get confused between BEGKA and BECKA), was not able to follow a heading, and sound to be far behind the airplane.

Posted

lets break it down

> no pilot may
> operate an aircraft ... below the authorized MDA
> OR 
> continue an approach below the authorized DA/DH

note it does NOT say "no pilot may operate an aircraft below the authorized ... DA/DH"

it DOES say "no pilot may .... continue an approach below the authorized DA/DH".  

a GO AROUND is not continuing an approach

Posted

also from TERPS 2-1-4. Sloping OCS:


"d. In the case of a missed approach procedure, the climbing flight path starts at the height of the minimum descent altitude (MDA) or decision altitude (DA) minus height loss. "

 

  • Like 1
Posted
12 hours ago, 1980Mooney said:

It is a decision if:

  • You must always be able to make a descent to landing on the intended runway using normal maneuvers and a normal descent rate,
  • The flight visibility (that you observe) must meet or exceed the minimums published for the approach, and
  • You must be able to distinctly identify one of the approved visual references for the runway (often called the "runway environment")..i.e "runway environment in sight"

If you cannot satisfy all 3 then it is a minimum.  

I think that wasn’t the point. There is a functional difference between an mda and da. 

Posted

So, where does all this TERPS discussion leave us with this mishap? Clearly, something didn’t go as planned.

In my thinking, there are still pieces of the puzzle to be fitted. Like, was he really receiving an LPV signal or was his GPS showing an LNAV for RWY14? Did he get an LPV indication for RWY14 but dove to the DA thinking he was dropping down to an MDA for a look see? Based on his ATC exchanges, how far in the back seat was he when he shot the approach?

Seeing that he was pretty expressive in post mishap conversations with the press, I’m sure the investigators will be able to piece together what type of neuron path he emitted during this event.


Sent from my iPad using Tapatalk Pro

  • Like 3
Posted
1 hour ago, 1980Mooney said:

He was definitely Scud Running.  I love this from the Prelim:

Before collision with the tower at 600 ft. elevation " the airplane descended as low as 475 ft. The published field elevation at GAI was 539 ft msl."

He was flying like a "ground hugging" cruise missile. If he looked at his altimeter and thought abought the elevation at his home base KGAI maybe he thought he was a submarine or would tunnel into the runway......

GAI.png.1c64a322285fd87af4550b0216c9f51a.png

Yeah, I caught that too (so did the controller). All his altitudes on the intermediate fixes were a few hundred feet off too. I love how quickly the FAA rebutted his “my altimeter must have been broken” argument. Seems from the prelim like his actions were quite intentional and not accidental at all. A shame this is such a black eye for the aviation community. It seems that airport had been struggling even before the accident and now it will probably lead to increased calls to shiut down “unsafe” GA airports since those spam can pilots don’t know what they’re doing. Should we link this to the “why are my insurance rates going up” threads?

  • Like 1
Posted
18 minutes ago, ArtVandelay said:

Did he have a radar altimeter, and maybe just using to fly minimum altitude?

I have a Radar altimeter and of course everything I flew in the Army did too.

If the earth was flat then they would be good for IFR, but it’s not so therefore unless you know the approach very well as in know where every hill and tower is and know where you are on the approach they aren’t necessarily that good. Then add in they often will read the altitude to a tree canopy or not depending on the season

I’m not sure how good they are in a GA airplane, mine of course has an alarm and a bug you set the alarm with, I guess the idea is to set it to the MDA in AGL and if it alarms, go missed.

Posted
On 12/6/2022 at 3:20 PM, A64Pilot said:

If the earth was flat then they would be good for IFR, but it’s not so therefore unless you know the approach very well as in know where every hill and tower is and know where you are on the approach they aren’t necessarily that good

this is why we have both DA and DH on the plate. 

Posted
On 12/6/2022 at 1:53 PM, 1980Mooney said:

He was flying like a "ground hugging" cruise missile

maybe what he wanted was a contact approach :(

>>> It's flown the same way as a visual approach, but you don't need the airport in sight. You need to remain clear of clouds, have 1 statute mile of flight visibility, and reasonably expect to continue to the airport in those conditions. Plus, the airport must have a published instrument approach.

 

  • Like 1
Posted
1 hour ago, rbp said:

maybe what he wanted was a contact approach :(

>>> It's flown the same way as a visual approach, but you don't need the airport in sight. You need to remain clear of clouds, have 1 statute mile of flight visibility, and reasonably expect to continue to the airport in those conditions. Plus, the airport must have a published instrument approach.

It does require a specific clearance, though, which I suspect may not be given when there are high obstacles off the end of the runway.

Posted (edited)
1 hour ago, EricJ said:

It does require a specific clearance, though, which I suspect may not be given when there are high obstacles off the end of the runway.

He was likely very low under 700ft agl flying in uncontrolled Golf airspace and going to non towered airport, why he would need ATC clearance for that flying? he was likely on CTAF frequency bellow radio/radar reception coverage: ATC tends to give up on anyone going low like that, on this occasion, they called for “low alert” but no answer…

https://www.law.cornell.edu/cfr/text/14/91.173

If he was in controlled airspace with Approach (or final with Tower), he will need contact clearance but I highly doubt “IFR contact approaches” (ground in sight?) are allowed at night with ATC? what about “IFR visual approaches” (airport in sight?) at night with ATC?

By day, 1 1/4 visibility & clear of clouds flying under 700ft/1200ft he could even call that (scud run) VFR: no clearance and no flight plan, by night, I would expect that would becomes 3nm visibility on higher ceiling minima? 

I gather this “ground contact business” tend requires more skills & luck than proper IFR on procedures to DA & MDA? life expectancy shrinks exponentially bellow DA & MDA on procedure at 0.5nm from runway let alone 3nm away on freestyle navigation, the most easy & obvious way to avoid ground & trees is to fly up away from them in clouds not go down to have a closer look

The pilot likely saw the ground on short final, this happens often at night in marginal weather with layered clouds, that does not mean he should go for it? ground under with no runway ahead: run to hide into clouds !

 

 

Edited by Ibra

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