How to Convert Knots to MPH, and More Unit Magic
using conversion factors to change units and confirm results

The boring way to convert knots to mph is to multiply knots by 1.15.[1] But this skips over some awesome unit magic.

Specifically, we can use conversion factors to change between related units. Let’s look again at how to convert knots to mph.

Suppose you’re traveling at v\ \text{knots}=v\ \frac{\text{nautical miles}}{\text{hour}}. Then,

    \[ v\ \frac{\cancel{\text{nautical miles}}}{\text{hour}} * \frac{1.15\ \text{miles}}{1\ \cancel{\text{nautical miles}}} = v * 1.15\ \frac{\text{miles}}{\text{hour}}} = v * 1.15\ \text{mph} \]

Did You Just Cross Out the Units?

I did! This is called a conversion factor,[2] and is based on the principle that anything multiplied by 1 equals itself. It is an easy way to convert between units, and allows us to solve a variety of aviation problems.

  1. This is actually more like 1.150779, but we’ll use the rounded version.
  2. More precisely, you may hear this called dimensional analysis or the factor-label method.

The Lost Airports of California’s Bay Area
locations of 60 historic Bay Area airports with several georeferenced airport images

Given its rich aviation history, from early experiments in lighter-than-air flight to the modern Fleet Week,[1] it’s no surprise there are old Bay Area airports waiting to be discovered.

What I didn’t understand, until finding this incredible resource by Paul Freeman,[2] was just how many airfields there used to be. With Paul’s blessing, I created this map of 60 airports in the areas of San Francisco, San Jose, Oakland, San Rafael, Santa Rosa, and Monterey.[3]

  1. If you’d like to learn more, SF Chronicle has a good overview. And if you’d really like to dive in, check out Aviation in Northern California 1910-1939: Vol. I, San Francisco Bay Area.
  2. While this post focuses on the Bay Area and a few surrounding counties, his site covers airfields across the country. Please consider donating if you also enjoy the site.
  3. I know that’s more than the Bay Area, but I was having too much fun 😅

10 Important Figures on the Instrument Knowledge Test
info about figures that are likely to appear and may be easy points

It turns out there is only a handful of figures on the instrument knowledge test that:

  1. Are likely to be asked about, and
  2. Could be easy points on the test.

These are the 10 figures I believe are worth a closer study.

How to Pass the Instrument Written Test
an approach to preparing for and taking the knowledge test

Update: The r/flying community strongly recommended using Sheppard Air to prepare for the instrument written test. I can’t personally recommend the software, but wanted to pass on the tip to future readers.

I had only planned to write about the figures in the testing supplement[1], but two experiences on the instrument written test motivated a second post.

  1. I was much more stressed than I expected during the test. This testing strategy helped me avoid (several) silly mistakes.
  2. My approach seemed to work! I only missed two answers (97%) on the final test.

It’s useful to break preparing and testing into three stages.[2]

  1. Months Before ~ Learn the Material
  2. Weeks Before ~ Find and Fill Knowledge Gaps
  3. Night/Day Of ~ Make the Most of Test Day
  1. You can find that post here.
  2. To keep focused, I used my system for personal task management. I added tasks for each publication chapter and each ground school lesson. Then as the test got closer, I added tasks for taking practice tests and filling knowledge gaps.

How to Improve ForeFlight With a Bay Area Content Pack
an overview of content packs and a download for the Bay Area

If you’re planning to fly in the San Francisco area, you should install a Bay Area content pack for ForeFlight.[1]

  1. This is short post; if you already know what content packs are, this link may be all you need.

Learn ForeFlight the Easy Way: With a Flight Simulator
a collection of simulator resources to build proficiency with ForeFlight

The best time to learn ForeFlight is on the ground. With a bit of practice, you can safely leverage its many features while flying. (And avoid figuring them out in the air!)

This post collects together several resources on how to connect and use ForeFlight with a flight simulator.

How to Upgrade Your Personal Task Management System
an approach to keep daily and weekly tasks focused on your priorities

I found this task management system useful as an Engineering Manager and Program Manager at Apple, as a student pilot, and now as I study to teach others how to fly. It helps align tasks with priorities, then focus on completing them efficiently.

Hello and Welcome!
an overview of myself and this blog

Jack O'Leary in Cessna 152 cockpit

My name is John O’Leary, although everyone calls me Jack.[1] Nice to meet you!

I am a private pilot in the Bay Area, training to be a certified flight instructor (CFI). I’m currently working on my Instrument Rating.

My (smart, beautiful, and supportive) wife suggested setting the goals for this blog in the first post. She’s usually right, so let’s do that.

This blog is meant to cover my passions: learning, teaching, and flying.

  1. I also go by Jules Altis in online communities (such as live streams or planning Microsoft Flight Sim fly-ins).