Resident pilot 121pilot, a captain for a major U.S. airline, authors a new column on Live and Let’s Fly called Ask Your Captain. His mission: demystify the flight deck and an answer any question you may have on the topic of flying.
Q: What’s the relationship between knots and MPH and why do airlines use knots?
A: This goes back almost to the dawn of flying and is connected to the nautical roots that many airlines have. A nautical mile is equal to one minute of latitude or 6,076 feet vs a statute mile at 5,280 feet. When your navigating using charts, the use of nautical miles because of its relationship to latitude makes navigation a lot easier. This is why ships and airliners use nautical measurements. This is a lot less relevant in today’s world of glass cockpits, and GPS where we aren’t taking sights with a sextant or plotting our position on charts like they did in the old days. But because it’s the convention, it’s still what’s used. If you want to convert knots (a knot is a nautical mile per hour) to MPH the conversion is 1 knot equals 1.15 MPH.
Q: Do you need perfect vision to fly commercial jets? Where do you learn: flight school or the Military? Do the airlines favor one or the other? Do you have to pass a physical and how often? Are there regular drug tests?
A: No, you don’t need perfect vision to fly commercially it just has to be correctable. Commercial airline pilots come from a variety of sources both civilian and military. The advantage military pilots have is that, at least for the fixed wing guys, most of them can get hired directly by a major and do not need to spend a few years at a regional airline first. I suspect that airlines tend to prefer military pilots for the simple fact is that there aren’t even remotely enough of them to fill the cockpits at US major airlines. Yes, we have to pass a FAA flight physical and hold a class 1 medical. First Officers are required to do it once a year and Captains have to do it every six months. And yes, we are subject to random drug testing.
Have a question for the captain? E-mail him at ask121pilot at yahoo dot com and you may see your question appear in a future column!
Knots equal nautical miles per hour. One nautical mile equals 1.15 statute or “regular “ miles. The term knots comes from the maritime traditions. The other relevant speeds are really the Mach speed, which is the measurement of the speed of sound. This varies a lot according to altitude, temperature, air pressure and wind speeds. The other 3 relevant air speeds would be IAS=indicated airspeed, GS=ground speed or how fast you’re going over the ground and TAS=true air speed, corrected for winds. These last 3 are ALL measured in knots.
This is obviously pre 911, but on a Lufthansa flight from Frankfurt to the US, on an A340, I got to sit in the cockpit for about 15 minutes as we were crossing the Atlantic. First off, what a view! I remember them telling me LH typically didn’t like to hire military pilots, because of a fighter jock mentality. Commercial flying from point A to B was too tedious for many of them. Things have likely changed since then,
I know!! It was great wasn’t it!? I got a chance to fly on LH as well from Frankfurt to Washington Dulles pre 9/11. It was a 747-400 back then and yes, they let me visit up there for almost an hour. It was out of this world !!
@David – I think LH’s continued preference for non-military pilots stems from the fact that most German military pilots on fixed wing aircraft are flying fighter jets, which is indeed very different from flying a passenger jet from A to B. Also, fighters often have only 1 pilot and 1 non-pilot crew (gunner/technician), so fighter pilots have often been trained to go it alone from the start of their career, unlike LH’s own pilots which are firmly inducted into the Multi-Crew mindset. It may thus be a different mindest indeed. However, military pilots flying transports, like the Transall, the A400M or the Airbus / Bombardier fleet of the Luftwaffe may be more suitable for commercial passenger aviation though, given their multi-pilot cockpit environments and a generally more “slow & steady” approach to flying compared to fighters.
Speaking a guy who flies with a lot of ex single seat fighter pilots I’ve never met one who gave me any cause to question their suitability to operate in a multi pilot airline environment. If LH won’t hire guys just because they spent 20 years in a single pilot fast jet they are being extremely short sighted.
Why are they called knots? Here is why and I quote:
“ Until the mid-19th century, vessel speed at sea was measured using a chip log. This consisted of a wooden panel, attached by line to a reel, and weighted on one edge to float perpendicularly to the water surface and thus present substantial resistance to the water moving around it. The chip log was cast over the stern of the moving vessel and the line allowed to pay out.[6] Knots tied at a distance of 47 feet 3 inches (14.4018 m) from each other, passed through a sailor’s fingers, while another sailor used a 30-second sand-glass (28-second sand-glass is the currently accepted timing) to time the operation.[7] The knot count would be reported and used in the sailing master’s dead reckoning and navigation. This method gives a value for the knot of 20.25 in/s, or 1.85166 km/h. The difference from the modern definition is less than 0.02%.”.
MPH would be stupid, they should at least use km/h which is the unit the majority of humans use.
“A nautical mile is equal to one minute of latitude.”
Thanks so much for this tidbit! Best thing I’ve learned today by far.