Tuesday, November 7, 2017

Logging landings/takeoffs and approaches

A given landing or takeoff can have many different attributes.  It can be day or night, short-field, soft-field, at a towered airport, on an aircraft carrier.  A landing can be touch-and-go, full-stop, or stop-and-go.  And of course, these attributes are not mutually exclusive: it's certainly possible to do a night short-field full-stop landing on an aircraft carrier with an operating control tower.

In fact, in MyFlightbook, there are over 60 different kinds of landings and over 30 different kinds of takeoffs (and I am periodically adding more).

And we generally want to know how many of each of these we did.

Broadly speaking, there are two approaches one could take to logging landings.  (Everything I discuss below also applies to takeoffs, but for brevity/clarity, I'll just refer to landings from here on.)

The most specific and unambiguous way would be to create an entry for each landing, and in each entry identify all of the relevant attributes.

Landing 1: full-stop, soft-field
Landing 2: stop-and-go, night, short-field, towered airport
This has a clear advantage: everything is crystal clear.  But it has two disadvantages: (a) it is harder to answer simple questions like "how many full-stop landings did I do?", since you have to look at each entry and add them up, and (b) the data entry is cumbersome and if you do a flight with multiple landings, you have to remember the details of which ones were which.

Of course, (a) above is easy for a computer, which can just sum up the subtotals and display those to you, but making (b) easy is...hard, since much of it is not something that can be reliably determined automatically.  (Touch-and-go vs. full-stop and day/night are the main things that can be auto-detected).

The simpler way is to accept some ambiguity about which attributes applied to which landings and instead just enter the totals.

4 total landings
1 was a daytime stop-and-go
2 were full-stop night landings
3 were on short fields
2 were at fields with a control tower
This is the approach that MyFlightbook takes.  There are a few key things to note above, though:
  • Figuring out things like 61.57(a)/(b) currency becomes a lot easier.  Indeed, in the example above, I can see from above that the 4 total landings reset my general passenger-carrying currency for 61.57(a) in the category/class of the plane, that my (combined) 3 full-stop landings reset my tailwheel currency, and that I need one more night-landing to reset my nighttime currency.  (Assuming, of course, that I've done the requisite takeoffs too...)
  • Note that they don't add up!  The total landing count is just that: the number of times that the wheels(/skis/floats) touched ground; everything else is a subset of that count, and the subsets can overlap.  The important thing is that each total stands on its own.  The only real requirement from a data consistency point of view is that none of the subsets can be greater than the total number of landings for the flight.
The advantage of this, of course, is that the data entry is much cleaner: if you have 5 identical landings, you don't have to create 5 individual landings, you just put in the totals.  After all, it's generally the # of each kind of landing that matters, not which one was which.  And besides, the latter can often be determined from context: if your flight went from ABC to DEF to GHI, you know what kind of runway ABC had, whether DEF had a control tower, and that you ended the flight with a full-stop, not a touch-and-go.

The disadvantage is that there is some inherent ambiguity, and the system can't add things up to determine things like the total number of landings - you have to tell it.

I take a similar approach (pun not intended) for instrument approaches as well.  There are over 40 different kinds of instrument approaches in the system, so if you want to know how many ILS approaches you did vs. RNAV approaches, you can track that.  As with landings, these can also overlap: an approach can be both an ILS approach and hand-flown, for example.  But what matters about approaches from an instrument currency point of view is simply the number of approaches you did on a given flight; if you want to simply describe them in your comments or in the "Approach Description"  property, that's great; you are, after all, supposed to record details about the approach somewhere, but there's no requirement that it be in any "structured" format - free-form text is fine

So it's fine to simply record "3" in the "Approaches" field on a flight where you did 3 approaches, and say "3 ILS 16R at Paine Field" in the comments; whether to explicitly record a property that lets you count how many ILS approaches you did is up to you.

Note that 61.51(g)(3)(i) also requires that you record "the location and type of each instrument approach".  You can, of course, do this however you like, e.g., writing in the comments "2 ILS-yankee approaches to runway 16R at Paine Field" and you'd meet this requirement.  MyFlightbook provides an "Approach Name(s)" property, though, for this express purpose.  

There are a few reasons for offering a separate field.  The first is that it declutters your comments.  The second is that the "Check Flights" feature (on the Logbook menu of the website) looks for this field to see if you've described your approaches, since teasing that out of comments can be...challenging.  And the third reason is that the iOS and Android apps have an "approach helper" feature: if you press the "+" button next to the approach count field, it offers a UI to make it easy to describe your approaches, and when you go back, it will append that description to the Approach Name(s) property and (optionally) increment the overall approach count.

And here I'll let you in on a little tip: you can use an abbreviated notation in either the Comments field or the Approach Name(s) and MyFlightbook will recognize it as an approach description and translate it into English when you hover the mouse over it on the website.  Use this format:
[#][Approach type][Runway]@[Airport code]
E.g. "3ILS16R@KPAE" means "3 ILS Approaches to runway 16R at KPAE".

This is the format that the approach helper uses