2ship, both established R-035 75X, not on same radial?
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Hi all,
Something weird came up during an MP test flight last week.
Both experienced vpilots, both done PATRO departure numerous times, both confirmed TCN 075X + TCN mode + CRS 035 set.
When #1 is established on the radial and #2 shortly after that, they notice they aren’t flying on the same radial, although EHSI shows them both on it.Any idea what is the cause of this?
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Long shot but …Nav mode?
If one is in Nav mode and set to stpt 1 the radial is not from the tacan but the steerpointSo is there a possibility that one pilot was set to NAV stpt 1 and the other to Tacan?
Red Dog
Reality if for ppl who can't handle simulation -
That was my initial thought too, but judging from both pilot screenshots it seems both EHSIs are in TCN mode
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…both pilots holding crosswind correction?
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That’s weird
Looking close at the pictures it looks like there’s almost 5 deg drift to the left. Where the noses are pointing at 035, true heading is closer to 030. Looking at the distance between the both of you, you are about 5 degree’s of each other. Also the datalink friendly wingman symbols are pointing a little of boresight from the own ship symbol. So it seems it has something to do with drift and/or true heading. Just my thoughts.
Greetz Terminator
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@Red:
Long shot but …Nav mode?
If one is in Nav mode and set to stpt 1 the radial is not from the tacan but the steerpointSo is there a possibility that one pilot was set to NAV stpt 1 and the other to Tacan?
Could be, but i see both EHSI in TCN mode……
:uham: Sorry, Red Dog, I did not see Focaldesign’s awnser.
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…both pilots holding crosswind correction?
That’s weird
Looking close at the pictures it looks like there’s almost 5 deg drift to the left. Where the noses are pointing at 035, true heading is closer to 030. Looking at the distance between the both of you, you are about 5 dergree’sof each other. Also the datalink friendly wingman symbols are pointing a little of boresight from the own ship symbol. So it seems it has something to do with drift andor true heading. Just my thoughts.
Greetz Terminator
That was my initial thought too. But we’ve placed WP2 dead on Patro gps coordinates and WP1 on the TCN, so if flying correctly on the R-035 you should be on the steerpointline, as #2 is.
However, looking at the first cockpit screenshot, of #1, he’s exactly on R-035 in TCN mode but is flying left of #2 and left of the waypoint.
Wind was 100° @ 4knts so indeed a little bit of crosswind form the right pushing to the left. -
I’ll bet that both ground tracks are actually on the radial and their noses are pointed into the wind to counter crosswind push - note the displacement of the FPM in the last picture…and he’s also leaning starboard.
Would be nice if the line for the radial could also be included in the first picture…that and weather-dope would probably tell the tale.
May the bridges I burn light the way
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I’ll bet that both ground tracks are actually on the radial and their noses are pointed into the wind to counter crosswind push - note the displacement of the FPM in the last picture…and he’s also leaning starboard.
Would be nice if the line for the radial could also be included in the first picture…that and weather-dope would probably tell the tale.
Tacview picture shows Patro location, where #2 has flown directly over, as was to be expected as he was tracking the steerpointline. #1 is showing off left, on both tacview as the 2 pilots screenshot HSDs. He flew next to it the whole time, while his CDI was on CRS 035 the entire time. If he would be drifting by wind, he would end up with a CDI deflection to the right.
That’s what I don’t understand. 2 planes, same weather, same airplane, same alignement but different locations. -
Assuming I’m reading the OP’s issue correctly….
Assuming lateral separation between the two planes of about 1500 feet and an average of about 16 miles DME from the TCN, the angular measurement between the two planes is just over 1 degree (1.0173 to be precise). So, both planes are on the same radial, the HSI is correct, the flying is precise, and the trigonometry is correct.
f1
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Assuming I’m reading the OP’s issue correctly….
Assuming lateral separation between the two planes of about 1500 feet and an average of about 16 miles DME from the TCN, the angular measurement between the two planes is just over 1 degree (1.0173 to be precise). So, both planes are on the same radial, the HSI is correct, the flying is precise, and the trigonometry is correct.
f1
So the difference is because one of the two (most likely #1) is flying a mere 1degr off the radial (or for example #1 approx 0.5 degrees left of 035 & #2 approx 0.5 right of 035?
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So the difference is because one of the two (most likely #1) is flying a mere 1degr off the radial (or for example #1 approx 0.5 degrees left of 035 & #2 approx 0.5 right of 035?
I should have stated almost both on the same radial at 1500 ft sep. Is HSI model in BMS precise down to 1 degree increments? What was actual separation between the two planes (large 1500 was assumed)? 500 ft separation and the angular measurement drops to about .33 deg, definitely on the “same” radial then.
f1
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The radial is not a cord over the ground but gets wider the further away your are from the station. So at 10 nautical miles from the station the beam is about 1.000 feet wide (500 ft either left or right from the centerline). At 18 nautical miles as shown in your picture… you do the math
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I should have stated almost both on the same radial at 1500 ft sep. Is HSI model in BMS precise down to 1 degree increments? What was actual separation between the two planes (large 1500 was assumed)? 500 ft separation and the angular measurement drops to about .33 deg, definitely on the “same” radial then.
f1Can’t tell anymore, somehow managed to delete the acme-file :s
The radial is not a cord over the ground but gets wider the further away your are from the station. So at 10 nautical miles from the station the beam is about 1.000 feet wide (500 ft either left or right from the centerline). At 18 nautical miles as shown in your picture… you do the math
Aha, learned something new, thx!
If it was in a manual, or Red Dogs Chart tutorial, I’m fully expecting to receive a RTFM comment now
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So the difference is because one of the two (most likely #1) is flying a mere 1degr off the radial (or for example #1 approx 0.5 degrees left of 035 & #2 approx 0.5 right of 035?
That’s my guess …. just a little, little bit off (± 0.5 degree) and the difference magnifies by the time you get to ~15 DME.
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Tacview picture shows Patro location, where #2 has flown directly over, as was to be expected as he was tracking the steerpointline. #1 is showing off left, on both tacview as the 2 pilots screenshot HSDs. He flew next to it the whole time, while his CDI was on CRS 035 the entire time. If he would be drifting by wind, he would end up with a CDI deflection to the right.
That’s what I don’t understand. 2 planes, same weather, same airplane, same alignement but different locations.This, and as pointed out elsewhere that the resolution of the TACAN gets flaky - actually as you get closer to the station and not farther from it…is this even modeled in BMS? - means that the over flying jet could actually be not “on top” but slightly off, and it would be more likely that the trailer is “on” the radial. Yes, I agree that both are indicating on the radial…and probably are (or should be) as far as their ground track would indicate wrt the station. How was -2 positioning himself as far as the section formation was being maintained - tight or loose? That could also account.
May the bridges I burn light the way
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How was -2 positioning himself as far as the section formation was being maintained - tight or loose? That could also account.
The were both flying heads down SID until overhead patro, takeoff was 20sec interval
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…curiouser and curiouser…I can’t help thinking that it has something to do with the wind, that your ground tracks are actually correct, and this is a trick of geometry somehow - I believe your instruments and your flying. I’m stumped.
