Am I the only one who still thinks we should teach students to time from FAF to MAP?

[Paul Cantrell]

There is an ongoing discussion at our school about the usefulness of teaching instrument students to time from the FAF to the MAP. One of the other instructors (an ATP who flies regional jets part 121) is of the opinion that GPS has supplanted that - that even flying non-precision approaches you'll still use your GPS to identify the MAP.

I'm probably just old school, but I figure that when the GPS system goes away, or you are flying some POS that doesn't have a good GPS in it, you'll still want to have been trained to start your timer at the FAF. I figure if I don't teach my students to do this now, they won't be in the habit of starting the clock at the FAF.

What do others think? If it changes anything this is helicopter IFR in the USA.

Paul

[Big Pistons Forever]

The only reason the procedure of timing FAF to MAP was adopted was because before the availablity of GPS positioning there was no other universal way to determine arrival at the MAP. Since using time as a proxy for distance run requires a accurate ground speed, something impossible to be sure of particularly as you descend closer to the ground, a GPS derived distance to the MAF will always much more accurate. That being said students should be exposed to the technique in case they ever have to use it. I see no reason to use it on every training approach though.

Related to this question however is the requirement to devlop a mental appreciation of the time/speed/distance calculation in students. That way when they make a data entry mistake and the magic box gives them a silly answer they will recognize it.

[mattpilot]

Uhm... Yea i've always made my students time the approach.

I guess the nay sayers never had a GPS failure (both receiver failure & no signal). I've had a few and don't trust those things completely - just like i don't trust half the equipment on board completely . Timing the approach is just another backup that adds to SA that should be done.

Also, the examiners in the area i instructed would fail the applicants if they didn't do it - despite having a GPS onboard.

[DB6]

In the UK you have to use timing (assuming no DME) since GPS is not approved as primary navaid. GPS is not approved for use in the airliner I fly either, beyond the IAF, so yes, timing is important. Don't know about the USA but if you're going to fly across the pond you need to know how to.

[woodcoc2000]

Well I was taught "time to see" and time to go-around; but have never used it since in the real world. I guess the only time it would be of any use is when you have a distance derived MAP (MAP at 1DME etc.) and your DME and GPS go out. Given that times are written on approach plates, the only thing that really has to be taught is hit the START/STOP button on the timer as you pass over FAF..

[SNS3Guppy]

Timing should always be performed.

[172_driver]

Anybody else uses the 5T's?

Turn
Time
Throttle
Twist
Talk

Works every time

[establishedonfinals]

I was taught to always time the approach even if there is a DME facility, as there is nothing worse than crossing the beacon, forgetting the timer and then not being able to calculate MAP (as I managed on my first shot at an NDB approach!) An 172, I was taught a smililar method using,
Time
Turn
Throttle
Talk
What's the twist?

[172_driver]

VOR approaches that don't have the station located at the aerodrome, and the radials to track inbound and outbound from the VOR are not the same. Twist the correct outbound radial as you pass over.

Other approaches have fixes along the final approach track defined by cross radials from another VOR. As you pass over the IAF, twist in the next fix to find out when you can descend further.

Two applications of twist I've come across.

[BelArgUSA]

I still teach "time" in 747 simulators...!

Obvious - timing for approach is rare nowadays - but still required at times.
Non-precision approaches... However rare we do these things.
That is part of a proper briefing.
xxx
I do not time for a precision approach procedure - But...
In some non-precision approaches, VOR or ADF approaches, you need time.
IAF to MAP should always be timed.
xxx
You could not land from a MAP as it is from "above" the threshold of a runway.
You normally approach/land with about 800 FPM descent rate. - Airline jets.
Meaning you need to know from WHERE is a landing becoming IMPOSSIBLE.
xxx
Suppose this - a non-precision approach, time IAF to MAP is 2 minutes.
At 800 FPM rate, and MDA 600 AGL, you will be in position to land 45 seconds before time is over.
So, be ready for a missed approach if you did not see your runway after 75 seconds after the IAF.
So simple - Is it that difficult...?
I agree - it is rare nowadays that procedures require time, yet, it is better to do it by the book.
xxx

Happy contrails

[Keygrip]

I do not time for a precision approach procedure

Just curious, BelArgUSA, when do you start your watch then, if you are part way down an ILS when the glide slope fails?

[Dan Winterland]

If the glideslope fails, you go around. Quickly converting to an unbriefed, unplanned and uncleared Non Precision Approach in a commercial airliner is not really a viable or safe option.

Timing comes from the days when there was no distance incdicators except markers or cross bearing from other beacons. As most ILS approaches in use use DME for distance and most NPAs are now effectively a RNAV overlay, timing is not really necessary.

In the real world, people just don't do it. I haven't timed an approach for years.

[Keygrip]

Who mentioned a commercial airliner - or multi crew - or "unbriefed".

Could a single pilot, PA28?, not brief him/herself "ILS, yada, yada, yada, in the unlikely event of glideslope failure, time to MAP will be..."?

Let's get really mean: Single pilot, light multi engine aircraft, asymmetric, one very sick passenger, very low on fuel, Cat1 minima weather, aircraft few miles behind has declared an emergency for an undercarriage problem and is likely to crash land on runway (and close it).

Go around, or start the watch? (or call Joe Patroni).

[BelArgUSA]

For Keygrip -

Read what Dan Winterland writes here above.
We do not time for a precision approach.
You are "going to" a Decision Altitude, not a MDA based on time.
xxx
I used to do that when I had a fresh IR on my licence,,,
With airlines, we never did for an ILS.
Glide slope failed. we would go around, come back for LOC approach (+new briefing with time).
xxx
IR students often do time their ILS approaches, and do like you describe.
In practice with 20,000 hrs line flying, never did, and G/S failure (alone) never happened.
And I do not teach this in jet/airline simulator training environment either.
xxx
I know your FAA/CFIIs are probably telling you to "time" from the FAF.
Do like they tell you... but -
I would instead recommend instead you monitor the audio IDENT for the ILS.
Like you do for an ADF/VOR approach.
If something does not work, or stops working, go for a missed approach.
xxx
All the best -

Happy contrails

[bArt2]

If the glideslope fails, you go around.

If the glideslope fails I would continue to the localiser minima which would be the briefed backup approach. This is not unsafe as you do not need to change your tracking nor your descend rate. If you are already below loc minima you would exute the missed approach.

Bart

[BelArgUSA]

to bArt2

I would not recommend to do that.
xxx
Ok, you mention a briefing, and alternate briefing, and... MAP briefing then.
It is getting quite confusing to the F/O and the F/E I would be with.
Since you tune the ADF on the LOM as well, why not brief for NDB approach as well.
Let us keep the things simple and clear in the flight deck...
xxx
I mentioned above, I have never seen a G/S failing separately.
If there is a G/S failure, I would go around and investigate the how and why.
Flew with many airlines... none did have such procedure.
Not even with Sobelair... I flew OO-SJP there in the 1970s...
xxx
Prochaine fois que je suis à BRU, on discute cela devant une kriek ou geuze.
Alleye - tot ziens...!

Happy contrails

[SNS3Guppy]

While timing has negligible value on an ILS with fully functioning components, I still strongly recommend always timing the approach, for several reasons. One is that it should become a habit. Get in the habit of starting the clock when you pass the FAF. It's certainly required for many nonprecision approaches, and may be required if you have to shoot a localizer approach. It's also an additional means of monitoring the approach you're flying, precision or otherwise. Time is an integral function of everything we do, and a basic part of the equation in how we fly. We travel so far in so much time, burn so much fuel in so much time, etc. Time is important. It's important an approach. Always get in the habit of timing an approach. If it's a universal habit, it's hard to forget when you go do an NDB or VOR approach. Always time.

It's well to say that a large commercial airplane won't complete an approach on the localizer if the glideslope fails, or that one never fails...but I've certainly had it happen, and certainly completed the approach on the loc. If you have the fuel and the time in your tanks to go around, it's generally recommended that you do so...including rebriefing the approach as a localizer-only approach. Especially if the localizer approach involves a series of step-down fixes. Don't assume that because you have a power setting and descent rate that was working on the glideslope when it failed, that you can keep using that for the non-precision localizer-only approach...all of a sudden the step down fixes and crossing restructions take on a lot of meaning.

One really needs to consider what one is flying and the circumstances under which it's being flown before speaking in absolutes, however. To say that one should never complete the approach on the localizer assumes that one has no concerns in the world about fuel, about going somewhere else, etc. Particularly in today's environment where many firms are taking away captain's discretionary fuel, where tankering fuel isn't what it used to be, and where a long trip is involved with few options...going around simply because the glideslope went out may not always be the best option.

A fuel reserve is required to depart, not to arrive. One may plan for adequate fuel, but it may not always be there on arrival due to a number of factors ranging from unforecast conditions to re-routing to equipment failures, etc. Upon arrival, we look at a cost of nearly ten thousand pounds of fuel if we have to go around; that can eat a considerable part of what we have left. With that in mind, it may be very appropriate and safe, depending on the nature of the arrival, existing conditions, etc, to continue without the glideslope; it's subjective and by no means an absolute. In that case, one will be grateful for having timed the approach.

Some years ago I was joining the localizer at an airport served by three roughly parallel ILS's. One was down following a lightening strike earlier. That left two approaches. As the glideslope can alive and was captured, it failed, and ATC reported that the glideslope was out. We were given the option to continue or abandon the approach. We were far enough out we had ample time, and elected to continue. Shortly thereafter the localizer failed. Owing to weather in the area, fuel, and the fact that there was a long line to go back around and try it again, and conditions were deteriorating, we were able to transition to the parallel approach with the help of ATC. I already had both plates available and had reviewed both approaches, and as was my practice at the time, had reviewd both with a glideslope failure in mind. While on the second approach, the glideslope also failed, and as we became visual, the loc also failed. All other traffic was diverted, and at that point we really didn't have diversion fuel (for reasons that aren't important here). We were the last one in. Massive electrical failures and problems downed all the approaches and the airport was closed to approaches for a time.

This is admittedly a rare sort of occurence, but it can happen. I've experienced it, and while I wouldn't base timing strictly on a rare experience, it's a good habit in general. Timing doesn't cost you anything, and if you get in the habit of always hitting the timer then you're consistent through all your approaches. It simplifies your practices. In a light airplane, I still check gear down in a fixed gear airplane...do I need to do that? No...the gear is always down. But it's an ingrained habit, and I do it univerally in whatever I fly to keep it as a habit. Timing the approach is the same way.

Time the approach.

[BladePilot]

Mods,
give SNS3Guppy his own forum, you could call it 'ask SNS3guppy'

[IO540]

In the UK you have to use timing (assuming no DME) since GPS is not approved as primary navaid

Reference please!!!

[my bold]

[what next]

Hello!

It's certainly required for many nonprecision approaches...

Not in our part of the world! When I got my instrument rating 20 years ago, timing approaches had long been deleted from the training syllabus (interestingly, "time-distance-checks" were still haunting us then... but they have disapperared in the meantime as well).

In order to make timing meaningful, you need to know your groundspeed accurately. You get accurate GS measurements from things like GPS, DME or INS. If you have either of them, you also have accurate position information. Much more accurate than what you will get from using your stopwatch and quick mental calculation. That's why we don't teach it any more.

I once flew with a guy who had the die-hard habit of pressing his stopwatch when he stated his approach. When I asked him one day, after how many minutes he expects us to be at minimums, he answered: "When the DME reads zero"...

Greetings, Max