"Hi" Approaches

[Python]

Quick question for you military aviators out there:

I am instrument rated and have heard military pilots refer to "high" approaches. I have seen charts labeled "hi-ils" or "hi-tacan" etc.. Civilian flying does not have these so I was wondering if I could get clarification as to what these approaches are about. More specifically, why or when are they used? How are they flown?

Thanks

 

[HH-60H]

Quick question for you military aviators out there:

I am instrument rated and have heard military pilots refer to "high" approaches. I have seen charts labeled "hi-ils" or "hi-tacan" etc.. Civilian flying does not have these so I was wondering if I could get clarification as to what these approaches are about. More specifically, why or when are they used? How are they flown?

Thanks

It's been awhile, but I think the only difference is that they start from a "hi" altitude.

 

[mmx1]

What I was taught in ground school (before I get stomped on by winged aviators)....

is that they're for tactical aircraft (jets) to rapidly descend from cruising altitude to an approach to conserve fuel by not twiddling around at intermediate altitudes.

You wouldn't want to penetrate with (4000-8000 fpm, IIRC) in a jetliner, but crew comfort is not a factor in tactical airframes.

 

[abracadabra11]

What I was taught in ground school (before I get stomped on by winged aviators)....

is that they're for tactical aircraft (jets) to rapidly descend from cruising altitude to an approach to conserve fuel by not twiddling around at intermediate altitudes.

You wouldn't want to penetrate with (4000-8000 fpm, IIRC) in a jetliner, but crew comfort is not a factor in tactical airframes.

This winged aviator won't stomp on shit. That sounds exactly right to me.

Then again, I don't fly jets - so the only HI-approach I've ever done was in one of the T-34 sims in Corpus.

 

[freshy]

What I was taught in ground school (before I get stomped on by winged aviators)....

is that they're for tactical aircraft (jets) to rapidly descend from cruising altitude to an approach to conserve fuel by not twiddling around at intermediate altitudes.

You wouldn't want to penetrate with (4000-8000 fpm, IIRC) in a jetliner, but crew comfort is not a factor in tactical airframes.

You pretty much nailed it but I think the main reason for these approaches is purely for the haze factor. Gives the old fat bastard running the sim a way to further torture and harass you. If you look at the outside of the chart it has the dashed lines around the outside edge. Ironically this matches perfectly with the E.P. chapter in Natops.

In real life, the gentleman will get vectors to final or just pick up a GCA if radar is up.

 

[FLY_USMC]

To further answer Pythons questions.....in plain terms for the civilian aviator....what we refer to as a "HI-ILS" or a "HI-TACAN" would in a sense would be just a descent profile from a higher altitude down to a "normal" descent profile for an ILS or TACAN approach. Almost all of the final portions of our "HI-Approaches" look exactly like a normal ILS or a normal TACAN...they just have some wickets tacked onto the approach plate to intercept descending from altitudes in the mid to high teens.

 

[jarhead]

not sure about the conserve fuel part ... i'd bet you'd save more fuel with a max range idle descent with vectors to final (or to the overhead if it's open) vice the ass pain you have to go through on most HI approaches.

Like freshy said, the dashed lines on the HI plates indicate it's an emergency procedure. 1500 hours of military flying, the only time I have ever shot a HI approach was for training... vectors to the overhead or vectors to final is the only way to go ...

S/F

What I was taught in ground school (before I get stomped on by winged aviators)....

is that they're for tactical aircraft (jets) to rapidly descend from cruising altitude to an approach to conserve fuel by not twiddling around at intermediate altitudes.

You wouldn't want to penetrate with (4000-8000 fpm, IIRC) in a jetliner, but crew comfort is not a factor in tactical airframes.

 

[PropAddict]

The sims guys always gave us some justification like, "Well, it's important to stay up at altitude longer in a hostile area to avoid being shot from the ground. Screaming down from 15Kft right over the field is safer than coming in and arcing over at 1000 ft then coming in on a three mile final."

But if none of you salty guys have ever done it. . .that would mean. . .a sim guy lied to me. . .

 

[WEGL]

not sure about the conserve fuel part ... i'd bet you'd save more fuel with a max range idle descent with vectors to final (or to the overhead if it's open) vice the ass pain you have to go through on most HI approaches.

S/F

Yeah, definitely not the way to go if you're looking to save gas. I've always been under the impression that they're used to duck through the weather, ie: penetrate an icing layer. But personally, if that was my goal I'd still be looking for vectors to final....

 

[Kycntryboy]

High and Nordo

 

[ea6bflyr]

Or if you want to get through a layer or multiple layers, hence, penetration.

-ea6bflyr

 

[Pugs]

Or if you want to get through a layer or multiple layers, hence, penetration.

-ea6bflyr

The one at Whidbey is specifically designed to keep you above, then get you through the altitudes for max ice accumulation quickly (or so they used to teach at IGS).

For those that haven't played up in Pac NW icing there is as bad as any place in the world. Cold mountains and the relatively warm air off the Pacific and Puget Sound makes ice build-up an almost instant thing

 

[webmaster]

The sims guys always gave us some justification like, "Well, it's important to stay up at altitude longer in a hostile area to avoid being shot from the ground. Screaming down from 15Kft right over the field is safer than coming in and arcing over at 1000 ft then coming in on a three mile final."

But if none of you salty guys have ever done it. . .that would mean. . .a sim guy lied to me. . .

I have done the HI approaches into Hilo, Kbay and Guam. One time the Hilo controller basically told me to standby while he pulled them out (probably told his buddies "check out what this idiot is asking for"). He reviewed it, gave me my instructions, and basically told me that he didn't think I could make it down in the P3.... we proved him wrong

For P3s, it is a good opportunity to practice either a combat approach profile or executing an emegency descent. Both are benign manuevers with varying ways to dirty the aircraft up to achieve the desired descent rate.

I can't honestly think of any true reason to ask for this type of approach in real IMC conditions for a P3. In any significant weather, over G-ing the airframe and excessive speeds would be a bad combination. Plus, depending on the approach while in IMC, from a HI position, you may not have the ability to slow down while still staying on the approach (continual descent).

 

[A4sForever]

A "HI" approach is one wherein the First & Second Officers are screaming:

"YOU'RE NEVER GONNA' MAKE IT " !!!!
"YOU'RE NEVER GONNA' MAKE IT " !!!!

Happened defacto many times "on the line" ... complements of ATC and competing traffic.

But seriously, we did 'em all the time when I was "in the service" of UNCLE ... we didn't even carry "Low" approach plates. Sometimes, just to mess w/ ATC's head, we'd request to "keep it high" until they were questioning whether or not we'd make it down ... then we'd roll onto our back, pull the nose through, and start down ... straight down.

 

[FLYTPAY]

Less plates to carry!