Paolo Pacini, Chief Pilot · EMB-505 Standard Practices Manual Rev 5 · 20 Aug 2026
“When you’re calculating VAP for a gusty crosswind, do you take half the wind as reported off the ATIS, or do you work out the headwind component first and halve that?”
| Method | ½ steady | Gust | VAP |
|---|---|---|---|
| Half the reported wind (ignore the angle) | 5 | 10 | 122 |
| Half the resolved component (10 × cos 40° = 7.7) | 4 | 10 | 121 |
Runway 10, wind 140 at 10 gusting 20, VREF 107. Both add the full 10 kt gust factor; that part isn’t in dispute.
Nobody computes a cosine on final. The clock rule gets you the same answer in your head:
| Angle off the nose | Headwind is roughly | Actual cosine | Of a 10 kt wind |
|---|---|---|---|
| 30° | 90% | 0.87 | 8.7 kt |
| 40° | ~75% | 0.77 | 7.7 kt |
| 45° | 70% | 0.71 | 7.1 kt |
| 60° | 50% | 0.50 | 5.0 kt |
At 40° you’d call it three-quarters of 10, so 7 or 8 kt. Half of that is 4. Same answer the trig gives, and the rule of thumb is within a couple of tenths of the real cosine at every step.
So workload isn’t really the argument. Both methods are a one-second mental sum. The question is which number the manual should state, not which is easier to fly.
Ignoring the angle pretends more of the wind is headwind than it is, so Method A is never lower than the resolved figure, at most about 3 kt higher at 60° off. It is not a safety argument either way, it is a house-standard argument.
“Half the reported” → the example is right, the rule is wrong. Delete the word component. 122 stands.
“The component” → the rule is right, the example is wrong. Example becomes 121.
“ForeFlight/the G3000 gives it to us” → follow up: “So is the manual’s method only for when the software isn’t available?” §2.1.10.2 is specifically the pre-software-load procedure.
The two subsections split by avionics fit. 2.1.10.1 is the software doing it; 2.1.10.2 is the pilot doing it by hand. So if he says ForeFlight or the G3000 gives them the number, that is 2.1.10.1 and the question still stands for 2.1.10.2, which is the fallback for aircraft on an older load.
Worth knowing: the fleet may be entirely on 23.00 or later, in which case 2.1.10.2 is legacy text nobody flies. That is worth asking, because if so the fix is lower stakes than it looks, and it is also worth asking whether the section should stay at all.
Line 3 says “the entire Gust value”, which read strictly could mean the full 20 kt rather than the 10 kt increment. Nothing else in the manual defines it. The worked example is the only thing pinning it down, since 107 + 5 + 10 = 122 only works if it means the increment. So the example is not decoration, it is load-bearing, and that is another reason it and the rule need to agree.
When the wind is on the nose, half-the-reported and half-the-component are the same number. Changing the wind to 140° is what separated the two methods for the first time.
“One on the approach tables, and I might be missing something. Is there a reason you’d brief and bug circling minimums by default on a non-precision, so the option to circle stays open, and then come down to straight-in once you’re committed?”
“I ask because the non-precision table says to bug circling MDA at the FAF, and I wasn’t sure if that was deliberate or copied from the circling table.”
“Yes, that’s how we do it” → you’ve learned the technique. Worth asking whether the manual should say so, since nothing in the table explains it and a new SIC would follow it literally.
“No, that doesn’t sound right” → bring the evidence below.
Word for word identical.
“What made me look twice is that the two tables aren’t copies of each other. They differ in the flaps, the speed, there’s a VOR needles check in one and not the other, and circling has three extra rows for the visual maneuvering. So the bug line stood out as one of the only bits that’s identical.”
| Non-Precision | Circling | |
|---|---|---|
| Row 8 config | Flaps 3 [FULL], slows to VAP | Flaps 3, maintain 130 KIAS |
| VOR needles check | present | absent |
| Ends at | Missed Approach Point (row 12) | Visual Descent Point (row 14) |
| Extra rows | , | Airport Environment In Sight · Inside protected airspace · Visual Descent Point |
“There’s one more thing that makes me think it’s a copy-paste. In the circling table the level-off row spells it out, it says ALT Capture at MDA, circling altitude, in brackets. In the non-precision table the level-off row just says ALT Capture at MDA, no brackets. But the FAF row above it says bug circling MDA. So within the same table the FAF row names circling and the capture row doesn’t. They should be the same altitude, shouldn’t they?”
| FAF row (bug) | Level-off row (capture) | |
|---|---|---|
| Non-Precision | at circling MDA | ALT Capture at MDA |
| Circling | at circling MDA | ALT Capture at MDA (Circling Altitude) |
The author added “(Circling Altitude)” in the circling table to be explicit. If circling minimums were also intended on the non-precision, you’d expect the qualifier there too, especially since it’s the more surprising choice. Instead the non-precision table has the unqualified term at capture and the qualified one at the FAF.
Circling minimums are normally the higher of the two published. Bugging circling on a straight-in would level you off above the applicable MDA, so you’d go missed while still entitled to keep descending.
“No rush on either. I’ll leave both as-is until you can look at the table properly, just didn’t want to change a procedure line without asking.”
“Last thing, no decision needed. §2.2.3 says pilots have to demonstrate CDFA proficiency, that’s Continuous Descent Final Approach, to a training or standards pilot before using it in low IMC. There’s no line item for that on the SOE form and nowhere named where it gets recorded. I’m going to add it as an SOE line item and point the manual at the form, unless you’d rather it live somewhere else.”
The SOE form has no non-precision approach items at all. Every approach item on it is glidepath or stabilized-approach framed. Given §3.1.3 exists and §2.2.3 calls CDFA (Continuous Descent Final Approach) the recommended technique, that may be a wider gap than the CDFA line itself.
VAPP definition in the Abbreviations list, confirmed Garmin-specific, not raising it.
| Term | Means |
|---|---|
| VAP | Approach speed. VREF plus the wind additive. Said “vee-app”. |
| VREF | Reference landing speed for that weight and configuration. The baseline. |
| Additive | Whatever you add to VREF for wind. |
| Headwind component | The portion of the wind actually blowing down the runway at you, once the angle is accounted for. The rest is crosswind. |
| Gust factor | Peak minus steady. In 14010G20 that’s 20 − 10 = 10 kt. |
| Bug it | Set the altitude alert reference. Already company language, the SOE form says “Build it, Brief it, Bug it”. |
| Straight-in / circling | Two sets of minimums published on the same chart. Straight-in = land on the approach runway. Circling = maneuver visually to a different one. |
| Non-precision | No glideslope. Lateral guidance only. Not a synonym for straight-in, a non-precision approach can be flown either way. |
| CDFA | Continuous Descent Final Approach. On a non-precision there’s no glideslope, so the old technique was “dive and drive”: descend to MDA, level off, then fly along at that altitude until you see the runway or reach the missed approach point. CDFA replaces that with one constant descent flown like an ILS, so a go-around starts from a stable descending state rather than a low-level drive. The +50 ft in §2.2.3 is part of it, you start the go-around slightly above MDA so the transition doesn’t dip below it. |