BlueRidgeDx

The /B designation means that the munition/component in question is aircraft installed and expendable. If it were /A instead, it would mean that the component is aircraft installed and fixed.

Hey Druid, I don't see the typo? Yep, CAT IIIB lowest mins are 150ft RVR and no DH. You're right, there are many airplanes out there certified to fly approaches to those mins. But to use the no DH option, the airplane must possess a fail-operational autoland system. (I'm also leaving out the Alert Height (AH) discussion, because I've never dealt with its application in the real world.) Anyway, for airplanes with a fail-passive system, a DH is required and must be no lower 50ft. To the best of my knowledge - and I can certainly be wrong - if a fail-passive system is used for CAT IIIb operations, the minimum RVR is 600ft unless there are special aircraft provisions to facilitate rollout. To get lower than 600ft RVR, you have to have an approved rollout guidance system such as an autopilot approved for rollout guidance, or a HUD. In the end, most of this stuff will be operator and airframe specific. To get to the lowest approved mins, the operator has to undergo lengthy Operational Suitability Demonstrations that can require hundreds of successful approaches/landings, gradually stepping down the mins listed in the OP SPECS. Double check those numbers, Sabre. The A-10 is Approach Category 'D', and the approach in question is the Straight-In ILS - labeled S-ILS 21L on the plate. A quick look at the Nellis approach plates reveal that the ILS approach to runway 21L has approach mins of 200ft and 1/2SM visibility (or 2400ft RVR). DCS doesn't report RVR, so you would use visibility instead. Fly the localizer and glideslope until you reach a barometric altitude of 2066ft (which is equivalent to 200ft radar height), and if you can't see the approach lights, go around. If you see the approach lights, you may continue down to 100ft AGL (or 1966ft MSL) at which time you must be able to see the runway environment, which is defined as the runway pavement, runway lights, runway markings, or the red "terminating bar" of the ALSF-1 approach lighting system. If you see any of those things, you can continue visually to land. If not, go around. There's a gotcha in DCS with the ALSF-1 at Nellis: They're presently located 1,000ft from where they should be, so don't use the red lights as a reference. No problem! :thumbup:

Decision Altitude (DA) is specified in MSL, and is associated with CAT I precision approaches. Decision Height (DH) is specified in AGL, and is associated with CAT II/III approaches. Minimum Descent Altitude (MDA) is specified in MSL, is associated with non-precision approaches (like TACAN), and is to be flown until reaching the MAP which is specified either by a DME fix, crossing radial, timing, etc. TACAN is actually a non-precision approach. As above, the most common type of approach - the Category I ILS - specifies a DA which is expressed in MSL. Only a few certain types of approaches - Category II and III ILS - specify a DH expressed in AGL. (I'm purposely leaving out GLS, MLS, WAAS, etc...) MAPs are not specific to an airport, they are specific to a particular approach to a particular runway. A given runway may have multiple types of approaches, for instance: Runway 23R at Wright-Patterson AFB has 3 unique ILS approaches (plus a LOC-only variation), an RNAV GPS approach, and two unique TACAN approaches. The MAP can be completely different for each of the non-precision approaches. Using my example, the MAP for the GPS approach is 1.6nm from the threshold at 1380ft MSL, while the TACAN MAP is 2.1nm away at 1320ft MSL. Finally, DA(H) is not common across the entire category of approach. The ABSOLUTE minima are, but ACTUAL minima for each approach to each runway is determined based upon local factors. See below: CAT I approaches generally have a 200ft DA, and require 1/2SM visibility. Alternatively, RVR can be substituted for visibility if available, with a minimum value of 1,800ft. Some CAT I approaches have higher minima than 200-1/2 due to considerations such as rising terrain, non-standard lighting, non-standard markings, etc. A few very special CAT I approaches have lower than standard minima (150ft DA, and 1400ft RVR), but those require additional siting requirements, are designated SAACR approaches, and require the use of a Flight Director down to DA. CAT II approaches have a Decision Height not lower than 100ft, and a required RVR of not less than 1000ft. Minima may be higher depending on available ground equipment, lighting, obstacles, etc. CAT IIIa minimum is RVR 700ft, and depending on aircraft capability, a DH may be required and will be not less than 50ft. CAT IIIb minimum is RVR 150ft, and depending on aircraft capability, a DH may be required and will not be less than 50ft. CAT IIIc is not currently used. Again, these are the absolute minimum numbers...all of them can be adjusted upward depending on numerous factors.

If I may...why the hangup on CCRP? CCRP isn't the primary method of employment for GP bombs in the A-10. That's what CCIP and dive bombing are for. CCRP is primarily used for delivery of IAM's (JDAM and WCMD), LGB's, Loft Rockets, and flares. The only time you'd be using CCRP for GP bombs is from medium altitude - using a level or toss delivery - in order to remain outside the MANPADS WEZ. I think we can agree that that isn't the most accurate delivery technique for dumb bombs.

I haven't tried it myself yet, but you should be able to spin the A-10 provided full rudder is maintained above stall AOA. Below stall AOA, sustained rudder application will lead to a sideslip departure and a Post Stall Gyration (PSG), but no spin. Full aileron input, or crossed controls held after the stall break will also result in a PSG. Roll authority is maintained into the stall. Using the ailerons while stalled increases sideslip and reduces aileron effectiveness. Failing those conditions, in a 1g stall, the airplane will simply enter a high sink-rate with reduced elevator effectiveness and some airframe buffet. In an accelerated stall, there is airframe buffet, a slight rolling moment, and a loss of elevator authority that can be observed as a G-break. In Beta 1 and 2, I usually got snap-rolls when flying in the chopped-tone. The rolling motion should be far less aggressive. I was never able to achieve a wings-level, high sinkrate, stalled condition. As I mentioned, things could be different in B3.

Thanks, mvsgas. I'll readily concede that I've never flown in a fighter, and that each airplane is different. I was really just reacting to the folks that think it's preposterous that a pilot can feel or hear things like that. There are a great many airplanes where the sounds and sensations aren't nearly as subtle as they apparently are on an F-16.

Not to get too side tracked, but despite their situation, they actually had quite a few options. I'm not one to pass judgement, especially on "teh internets", but those two guys made a LOT of REALLY bad decisions. It's very sad, because they certainly didn't go flying that night with the intention of getting killed. The best we can do is learn from their mistakes. I learned a lot about the airplane that I didn't know from that accident, and even more about the human factors that precipitated it.

Ok, well, no harm no foul. But to be fair, I thought his post pretty explicitly addressed US vs. International procedure and usage. No biggie. I'm just sayin'. :) PS - Can you say what you're flying? I'm not sure FRED can generate 2 sorties in a week, lol. So that leaves Tankers, Herks, and a few things that start with "E".

Hmmm. Do you do much international flying? FL90 is a perfectly valid altitude depending on where you're flying in the world. In much of the rest of the world, as has been stated several times in this thread, the Transition Altitude is much lower than the standard 18,000ft here in the US. FL's below 180 look weird to us Americans, but they exist. It would be a little less ambiguous if they put in the leading zero, but they don't. As such, FL90 is translated as 9,000ft. FL900 would be 90,000ft.

The Delta mode is certainly simulated, though I don't know about the automatic update during takeoff. I would assume it's there, because you have the ability to go into the Delta Cal submenus with the IFFCC switch in TEST. So evidently, they've fleshed the system out pretty well. I actually mentioned this error in another thread that ended up getting pretty badly derailed. It had to do with ILS frequencies and the associated DME channels. I'm not sure that anyone from ED ever actually acknowledged the issue, but they probably know about it...I think. Not sure which forum would be best...General, Avionics, and Model Errors seem like good candidates to me. I reserve the right to be wrong, though.

Even better effort! I might mention that at least in the US, the military uses QNH just like everyone else. There's a caveat of course, in that the A-10 will set the altimeter to whatever is required in order for the altimeter to read TDZE during takeoff (QFE). They do this so the IFFCC can take a Delta update during the takeoff roll - it happens automatically at about 70kt. After takeoff, they're supposed to return to QNH in order to ensure appropriate seperation.

Good effort. But minimum vertical separation is 1000ft. It used to be 2000ft above FL290 prior to RVSM.

I'm envious that you got a ride in the viper, and I hear what you're saying. Please don't take this the wrong way, as I genuinely don't mean anything negative by it, but having flown in something one time, all the noises, vibrations and sensations were probably new to you. So it's quite possible that you simply missed these subtle cues amongst the "background noise" of everything else. If I were ever able to sandbag a viper ride, you can bet that my attention wouldn not be focused on gear retraction either. But I'm willing to bet that if you (or anyone) flew in something, say, 20 times, you'd be far more in-tune with the machine, and would be able to pick things out of all the background noise. I don't know how noticeable these things are in an A-10 or an F-16...maybe you're right. All I'm saying is that it's not a "stupid" concept that a pilot could feel/hear these things. Quite often, you can.

Not sure how that relates? I was referring to the aural and physiological "feedback" that an A-10 pilot experiences in the cockpit. My point was that an A-10 is no different than any other airplane, in that open gear doors increase wind noise, rapidly moving (and very heavy) landing gear components impart large forces on the airframe, and hydraulically actuated components operating at 3,000psi given a certain feedback.

LOL... I spent a few hundred hours strapped to the cockpit door of the J-41 commuting to/from work, so I don't need to rely on anyone else's interpretation. ;) Same can be said for the CRJ-200/700, A319/320, 737-400, SF340, 767 and the DC-10...again, I experienced it with my own butt in the cockpit, so... Can't speak about the Chieftan as I've never flown one - though I did almost have a mid-air with one in a CRJ descending into Burlington, VT but that's different story. But I've had the pleasure of riding up front on the MD-88 several times, and it is easily the best example of the phenomena I explained... even light braking results in a distinct low frequency vibration in the front of the airplane. The sound of the oleo uncompressing during rotation is unmistakeable. The increase in wind noise as the gear doors open is significant. Finally, the vibration and thumping from the nose wheel contacting the snubber feels like someone beating on the bottom of the jumpseat. Just my unsolicited two cents...

I realize we're talking about fighters here, but you can feel the gear coming up and going down (in the cockpit) in everything from a J-41 (twin turboprop) to the DC-10... I wouldn't call those "small stuff". It's a combination of things: 1) Gear doors open causing a noticeable increase in wind noise. 2) The hydraulic actuators for the gear are pretty stout, and you can feel it when they start moving. 3) There is a perceptible "bounce" in the cockpit as the nose gear starts moving. 4) Once the wheels are in the wells, the wind noise is drastically reduced. 5) You can hear and feel the shimmy as the nose wheel rubs against the "snubber" used to stop wheel rotation...the wheel well is right under your feet. Does an A-10 pilot expereince the same feedback? I don't know. But all the same mechanics and functions are there.

It's probably not what you had in mind, but you can acheive the ultimate HUD declutter by switching the HUD mode switch to STBY. Doing so will remove all symbology except for the Standby Reticle. The Standby Reticle is depressible - about 9 mils will get you close to the usual GBL location, and 41 mils is about where the TVV settles in level flight at 300kt. The A-10C HUD is already pretty well decluttered considering that airspeed and altitude are already displayed in digital format, and several other IFFCC display options are off by default (Airspeed/Altitude Tapes, the Radar Altitude tape, Vertical Velocity Tape, etc.)

That field will display the best available AGL altitude source. Radar altitude has priority, but DTSAS derived altitude will be displayed if outside of RADALT range, or if the RADALT is off/unserviceable.

The nomenclature "ALT SCE" is slightly ambiguous, but refers to Altitude Source, not Altimeter Source. The ALT SCE is used for IFFCC weapon delivery computations, and is used to derive aircraft altitude above the target. The data is used internally within the IFFCC for CCIP/CCRP functions, and has no effect on the HUD displayed altimetry. In Radar Mode, the IFFCC assumes that the height above target is equal to the radar height directly below the aircaft. As such, it's only useful over flat terrain, and it's subject to the 5,000ft AGL limitation of the radar altimeter. The Baro and Delta modes are far more complex, and the specifics aren't really germane to the OP's question. Suffice it to say that these modes incorporate the CADC, EGI GPS altitude data, and various methods of updating and calibrating this data to derive an actual MSL target altitude. Additionally, as someone already pointed out, the aircraft uses a DTED elevation database to determine target elevation. Using this database, the IFFCC can provide the elevation under the gun/bomb/maverick/depressible pippers. Alternatively, the TGP can also be used to determine target elevation provided you have actively lased the target.

All of that aside, the 5000ft limitation is a result of the radar altimeter's limited range. The reflected energy isn't sufficient enough for the receiver to acheive a reliable lock above 5000ft, so the display is limited to that value. There's no way to force the radar altimeter to display data above this height.

I briefly worked for an airline that lost a CRJ due to a high-altitude upset that resulted in a dual-flameout. For those who aren't aware, the CRJ has the same basic engine as the A-10. After stalling at FL410, the airplane experienced pitch and roll oscillations that resulted in high pitch attitude (~30 degrees), high alpha (~30 degrees), low airspeed (75KIAS), and high power setting (98% N1). The net result of this was a dual-flameout and subsequent "core lock" of the engines. Core lock is when the N2/HPT spool is physically prevented from rotating due to physical contact between rotating and stationary parts caused by rapid differential cooling experienced during engine failure/shutdown at high thrust or ITT/EGT. During the upset, the engines suffered N1 rollback and stagnation, followed by flameout. Because of the extremely low airspeed, the #2 engine ITT spiked above 1250*C. The engine was so hot, that the HPT blades melted and lost 80% of their surface area. The molten metal actually flowed aft into the LPT section where it resolidified into long strands. So yeah, heed those Dash-1 warnings concerning engine disturbance and flameout susceptibility regions. It will ruin your day. You can read about the accident here: http://www.ntsb.gov/events/2005/pinnacle/exhibits/default.htm

I'm not trying to get wrapped up in this, but I'm not sure what you're saying here? N1 is the abbreviation for Fan Speed; N2 is Core Speed. This is universal across turbojet/turbofan engines. ***Yes, before somebody says it, some RR engines are actually triple spooled and have N3, but that's irrelevant.***

The depressible pipper can be used for a variety of things: It's used for manual bombing, obviously, but it also aids in the boresighting of Mavericks, can be used as a "set track" reference when pulling to the Aim-Off Point during roll-in, etc.

The A-10C's VMU doesn't have a "BINGO" alert message.

Exactly. :thumbup: