VOR/ILS Question

3Y3Flyer

3Y3Flyer

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3Y3Flyer
Curious, would a handheld NAV radio be acceptable as a second nav radio for the purpose of logging dual VOR checks every 30 days against a 430W? Second question...this came up in discussion over coffee....can you legally fly an ILS or LOC approach without having a current nav check within the last 30 days?
 
Does the wording of 91.171 give any hints?

91.171(c): "If dual system VOR (units independent of each other except for the antenna) is installed in the aircraft..."

91.171(a): "No person may operate a civil aircraft under IFR using the VOR system of radio navigation unless the VOR equipment of that aircraft..."
 
There is that tricky word again....”installed” in the aircraft....damn thing is on a ram ball mount and hooked to ship power...seems “installed” to me.
 
DMSPILOT ended the thread quick.

No handheld is acceptable for ANY non-emergency purpose in IFR.
Without a proper VOR check in the lookback period you're out of luck.

And since the question is answered, I'll kick it back to the OP...

How much latitude do I have on landings at night for carrying passengers? Do I really need to keep up on holds to be current, or are approaches good enough? If I do 7 approaches in VMC without a view limiting device and safety pilot am I current.

And while I've been typing you asked about mounts and power source. I guess you'll be flying the first ever IFR iPad.

sheesh.
 
3Y3Flyer said:
There is that tricky word again....”installed” in the aircraft....damn thing is on a ram ball mount and hooked to ship power...seems “installed” to me.
Click to expand...

Is it part of the weight and balance and equipment list?
 
No ravioli...it was a simple question and discussion that came up around some airport bum conversation...I don’t intend to go do an IMC to min landing with the old iPad. However, in this case you are checking accuracy of a signal from one device to another, if two devices read within 4 degrees, is it accurate and acceptable. The argument came up on the ILS from one gentleman that claimed VOR checks don’t check glidslope...true, so you should have that tested at annual and not rely on VOR checks. That brought around the discussion of checking GS at FAF...blah blah blah....on and on. Was just a simple question to see other opinions.
 
3Y3Flyer said:
However, in this case you are checking accuracy of a signal from one device to another, if two devices read within 4 degrees, is it accurate and acceptable.
Click to expand...

Each device needs to be legal in order to be used in the comparison. What more discussion is needed?
 
For your second question, there is no required check for an ILS receiver. Therefore, yes, you could be >30 days since your last VOR check and perfectly legally fly an ILS - as long as you didn't need VOR navigation to get there, or as part of that approach.

VOR and ILS are two completely different technologies and sets of equipment. That fact that most modern manufacturers have chosen to include both of them in the same radio and indicator doesn't change that. I assume that at some point decades ago, you would have a separate VOR receiver and ILS receiver.
 
I think @RussR makes a logical point. If you're horizontal guidance is so whacked you can't get established on the ILS you're hosed. But if you are established than you SHOULD be okay.

meanwhile, what say regs about VOR checks? I recall their being some other way then comparing two legal VOR/Indicators while in flight.
 
Another way is to use a VOT, (VOR Test) which is a signal transmitted at some larger airports...or it used to be! The AIM should show whether a particular airport has that capability.
 
VOT info from AIM:

VOR Receiver Check
  1. The FAA VOR test facility (VOT) transmits a test signal which provides users a convenient means to determine the operational status and accuracy of a VOR receiver while on the ground where a VOT is located. The airborne use of VOT is permitted; however, its use is strictly limited to those areas/altitudes specifically authorized in the Chart Supplement U.S. or appropriate supplement.
  2. To use the VOT service, tune in the VOT frequency on your VOR receiver. With the Course Deviation Indicator (CDI) centered, the omni-bearing selector should read 0 degrees with the to/from indication showing “from” or the omni-bearing selector should read 180 degrees with the to/from indication showing “to.” Should the VOR receiver operate an RMI (Radio Magnetic Indicator), it will indicate 180 degrees on any omni-bearing selector (OBS) setting. Two means of identification are used. One is a series of dots and the other is a continuous tone. Information concerning an individual test signal can be obtained from the local FSS.
 
For example, the Chart Supplement for the southwest shows that KCOS (Colorado Springs) has a VOT on 110.4 MHz.
 
Ravioli said:
I think @RussR makes a logical point. If you're horizontal guidance is so whacked you can't get established on the ILS you're hosed. But if you are established than you SHOULD be okay.
Click to expand...
The LOC and VOR are completely difference technologies.

The VOR transmits two "tones", one via AM and one via FM. One of the tones is omnidirectional--the signals received is identical regardless of the receiver's position. The other tone is phased and the phase-received is dependent on the receiver's position. The VOR equipment compares the phase of these two tones, or signals, to determine the receiver's position.

This can be visualized by imagining a tower in an open field. On top of the tower are two lights. One is a strobe light that can be seen from any direction. The other rotates, like an airport's rotating beacon with its white lens blacked out (only one flash per rotation). The rotating beacon rotates at one-degree per second taking 360 seconds to complete one rotation. The strobe is synchronized to flash when the rotating beacon is pointing directly north. An observer can determine his position by starting a timer when the strobe flashes and timing how many seconds pass before the green rotating beacon is observed. 90 seconds is the 90deg radial, 180 seconds is the 180deg radial, etc.

The OBS knob on a VOR nav display is a phase shifter. It shifts, or moves, one of the signals so that they'll align, be in phase, when on the selected radial. The needle displays the difference between the two signals; centered when they match, full scale when more than 10deg apart, and in between when within 10deg. The phase shifter must be accurately calibrated to match the course selected by the OBS. It is this phase shifter calibration that you are testing when you do a VOR check.

The LOC doesn't depend on a phase shifter or OBS course readout in the airplane. The calibration is done on the ground through the transmission pattern of the two lobes (90Hz and 150Hz). The CDI is showing the relative strengths of the two lobes which indicates position between them. The VOR phase shifter and OBS setting are bypassed. There is nothing to calibrate.
 
Thanks for the responses...I wondered if that 30 day check had any bearing on ILS usage, and I’m glad to hear it doesn’t. We have a 430W in the Cherokee, and have pulled out the old Narco Nav when it died, so dual checks are no longer available. Put a sporty’s nav/com in the plane for emergencies. The nearest VOT is in KDSM, a bit of a hassle. We have been doing our checks with ground reference and radial, but that’s a 6 degree tolerance...that checks the legal box, but it seems to me cross checking the handheld and 430, tightens up the accuracy tolerances a bit, plus tests both primary and backup devices at the same time. I have flown on that Sporty’s hand held a few times to practice, and I would have zero concerns using it on an actual approach, if needed...very accurate. Just my two cents, and why the post.
 
There's nothing wrong with you checking your VOR against non-approved sources for your own information. You just can't use it as the VOR check required for IFR currency. Use the airborne check for legality. Use both the results of the airborne check, and your unofficial checks, to maintain your own awareness of your VOR's accuracy.

I have very little experience using the 430W for IFR flying but, as I recall, there are situations where the easiest/best way to navigate certain clearances is by using the 430's VOR function. For that reason, I think it is worthwhile to keep doing those airborne checks to keep it IFR current.
 
3Y3Flyer said:
Thanks for the responses...I wondered if that 30 day check had any bearing on ILS usage, and I’m glad to hear it doesn’t. We have a 430W in the Cherokee, and have pulled out the old Narco Nav when it died, so dual checks are no longer available. Put a sporty’s nav/com in the plane for emergencies. The nearest VOT is in KDSM, a bit of a hassle. We have been doing our checks with ground reference and radial, but that’s a 6 degree tolerance...that checks the legal box, but it seems to me cross checking the handheld and 430, tightens up the accuracy tolerances a bit, plus tests both primary and backup devices at the same time. I have flown on that Sporty’s hand held a few times to practice, and I would have zero concerns using it on an actual approach, if needed...very accurate. Just my two cents, and why the post.
Click to expand...

Since you have a 430W and assuming a current database, a VOR check is not required unless you actually plan to use the VOR for IFR navigation (versus the GPS). That said, I would continue to do the VOR checks, but I wouldn't go out of my way to do them or worry if it had been a while. Just each time you're close enough to a VOT or an airborne checkpoint, or cross an airway, log it. When I used to have this situation, I operated out of an airport that was pretty close to a VOT. I left the VOR tuned to that VOT unless I actually needed it for something else, which means that every takeoff I was doing a VOR check, if I chose to log it.
 
Arrow76R said:
VOT info from AIM:

VOR Receiver Check
  1. The FAA VOR test facility (VOT) transmits a test signal which provides users a convenient means to determine the operational status and accuracy of a VOR receiver while on the ground where a VOT is located. The airborne use of VOT is permitted; however, its use is strictly limited to those areas/altitudes specifically authorized in the Chart Supplement U.S. or appropriate supplement.
  2. To use the VOT service, tune in the VOT frequency on your VOR receiver. With the Course Deviation Indicator (CDI) centered, the omni-bearing selector should read 0 degrees with the to/from indication showing “from” or the omni-bearing selector should read 180 degrees with the to/from indication showing “to.” Should the VOR receiver operate an RMI (Radio Magnetic Indicator), it will indicate 180 degrees on any omni-bearing selector (OBS) setting. Two means of identification are used. One is a series of dots and the other is a continuous tone. Information concerning an individual test signal can be obtained from the local FSS.
Click to expand...
You can also fly over a prominent landmark on a map and radial intersection for single VOr check with a error of +/- 6deg I believe as well.
 
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