F-16 ILS approach speed/technique
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What speeds to use during the different phases of an instrument approach?
300 knots is penetration speed
but 250 is also acceptable if you’re behind the jet
300 knots at all times below 10K, on a straight in ILS or other approach fly your on-speed approach speed5nm prior to final approach fix/glideslope intercept: before-landing checklist, gear down
Now what, exactly…
Am I slowing to a speed so that when I intercept the glideslope, I follow it all the way down to minimums at 11 degrees AOA ?
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I’ve heard max 250 KIAS from the initial approach fix. ??
As far as your last, I think maybe it would be re-worded slightly …. Intercept and maintain glideslope at an AoA of 11 degrees. Reason is that speed will change with aircraft weight (?and other factors), so you can’t focus on ‘one correct speed’ … it’s ‘one correct AoA’ instead.
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there are no absolute numbers for this type of approach or any other - weight being the main factor.
but as you asked here are some numbers to work with assuming your not grossly under or grossly over weight. between 2,000ilbs and 5,000lbs fuel and hopefully no major A/G ordinance.
Approach 300kts - 10 miles out 285kts - 8 miles out airbrakes and set throttle to 80% - 6 miles (speed below 285knts) gear down - hold 80% throttle adjust as required to achieve speed of 165kts at touch down - leave the “flare” until you can get it nicely on the ground, chop throttle (idle) - nose up so HUD carret is in bottom half of bracket - nose will drop on its own at about 8knts - brakes down to 10knts to exit runway - airbrakes in below 60knts - taxi 20knts on the straights and 10knts in the turns.
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I understand that there is not a specific approach speed and you fly AOA. That’s why I said slowing to a speed to attain 11 degrees AOA. Sorry, I should rephrase the question.
Do they intercept the glideslope at 11 degrees AOA, and maintain this for the entire duration?
Or do they intercept and slow down during the descent on the glideslope, gradually reaching 11 degrees?
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I was taught (in BMS) to put the flight path marker at the top of the AoA bracket, i.e. fast, and fly that all the way down the glideslope. IRL …. …. not qualified to say (or guess).
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Usually from IAF to a little before FAF (or interception of Localizer course) [depends how much is the “little” each time] they come with 300-250 KIAS.
Now the procedures are not the same, even if we are talking for the ILS ones. So depending from its type, its on the pilot to “see” at where exactly he will slow to an airspeed that will be the best “match” for his final approach segment.
Of course there is always the ATC that follow and take care the traffic, that means that may advise the pilot to maintain a specific airspeed for separation reasons at some portion of the procedure.
Last from a lot of real military pilots that I have asked here in Hellas (ex Greece), they fly the AOA. Means they don’t follow a specific speed/distance way, but they keep either a 11 deg. AOA or (some of them) 13 deg.
A crosscheck always be made according to weight and speed, but they use the AOA.
Nikos. -
Yes Agave_Blue I was wondering about IRL.
I was thinking flying 11° from FAF/glideslope intercept all the way down to minimums seemed awfully slow. Thinking about ATC saying: “keep your speed up”
Sounds like the answer is it depends.
In the end, as long as they reach 11-13° sometime before minimums, they will be in good shape.
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I was thinking flying 11° from FAF/glideslope intercept all the way down to minimums seemed awfully slow. Thinking about ATC saying: “keep your speed up”
No, don’t have problem with this.
Sounds like the answer is it depends.
Correct.
In the end, as long as they reach 11-13° sometime before minimums, they will be in good shape.
Yes.
