Spencer Suderman recently did a world record 81-turn inverted flat spin, and dropped over 21 thousand feet while doing so. The entire thing is documented on youtube. The spin starts at 3 minutes into the clip. Looking at the footage, in the beginning of the spin, and also (although to a lesser extent) at the end of the spin, the altimeter is unwinding very unevenly, being almost steady for a second and then quickly unwinding 3-500 feet before steadying (or actually increasing the first couple of turns) for another second. Why is that? It seems unreasonable to me that it would actually be leveling out.
It's worth noting that in the middle of descent, when spin is perfectly flat, it's unwinding evenly.
The altimeter works by measurements of the pressure in undisturbed air, also called static pressure. A static port is placed, usually on the side of the hull, perpendicular to the airflow.
During a spin, the airflow will not flow evenly past the static port, but will occasionally flow directly onto the static port. This will cause a rise in measured pressure, leading the altimeter to believe it is lower than it actually is. This cause fluctuations in the indicated altitude.
DeltaLima's answer is correct, but he doesn't say why there are oscillations. If you watch the horizon, you will see that initially and at the end of the spin the roll angle oscillates, whereas in the middle of the spin the roll angle is steady. The uneven altimeter correlates nicely with this roll oscillation. I assume that the static ports are at the rear fuselage, and during a spin the airflow will have a noticeable sideward component there. This will influence the pressure on the static port, and an oscillating change in this sideward component causes the halting movement of the altimeter.
Spencer Suderman recently did a world record 81-turn inverted flat spin, and dropped over 21 thousand feet while doing so. The entire thing is documented on youtube. The spin starts at 3 minutes into the clip. Looking at the footage, in the beginning of the spin, and also (although to a lesser extent) at the end of the spin, the altimeter is unwinding very unevenly, being almost steady for a second and then quickly unwinding 3-500 feet before steadying (or actually increasing the first couple of turns) for another second. Why is that? It seems unreasonable to me that it would actually
How do flying wings, like the B-2 Stealth bomber, actually keep themselves from yawing out of control without a vertical stabilizer? For the record, I assume this has to be a simple mechanics... speeds, well, that and the ground effects were pretty strong. But, no mentions of going into flat spins when going into hard maneuvers (that I recall). So how do they control that Y axis on flying wings? Are they perhaps more susceptible to a flat spin than a regular design (even if those risks can be kept to an acceptable minimum)?
Non-precision instrument approaches generally have altitude restrictions which get lower when you get closer to the airport. I always figured these restrictions were AMSL using the current altimeter setting, not compensating for temperature. Some have heard the mnemonic that mountains are higher come wintertime, which basically means that colder weather make your altimeter read higher than you actually are (or, as most pilots prefer to think, you're lower than what your altimeter reads) Have a look at this VOR approach into Newark Most altitude restrictions are a minimum level, so
Are airspace violations (e.g. entry to class B without clearance) based on primary radar and/or Mode C transponder, or something else? I read that Mode C altitude is based on pressure altitude, i.e.... (hypothetically), just winding back the altimeter pressure reading to appear to be at a lower altitude? So to summarize: How are airspace violations detected: What data input is used? If Mode C reading is used, is it based on pilot's altimeter? Would winding back the altimeter make a plane report a lower altitude?
On this approach plate, the holding pattern shown is depicted for a missed approach: However, in the notes, it says to Descend to 6000 in holding pattern. even though you should only climb to 4700 feet, according to the missed approach procedure: Climb to 3000 via 166° bearing then climbing left turn to 4700 direct DUT NDB/DME and hold. What does the note actually mean (especially since it seems to be implying you would be higher than 6000 on the missed approach procedure)?
for ATC to issue a descend via clearance, though I could be wrong about the second part. Some charts say "VERTICAL NAVIGATION PLANNING INFORMATION" before the expected altitude, so my assumption... though it's not required? How common is it for ATC to actually issue a "cross [fix] at [altitude]" where the fix and altitude are as expected on the chart? And, if it is common, why wouldn't it simply be mandatory? Are expected altitudes part of lost communications procedures? Am I missing anything with regards to the purpose of expected altitudes?
this to happen? (My guess is it is CG related) And most importantly: If I would have continued this "mushing" flight, would it be possible to have entered a flat spin or a simple "drop out of the sky...When I took delivery of a new Cessna 182T last year, I did a test flight for certification purposes. During the test flight we had to perform a power off stall but that didn't go as planned.... This "mushing" went on for what seemed ages before I eventually applied power and pushed the nose down to gain airspeed again. We tried it again after that and the same thing happened. I had an instructor
See Wikipedia:Drag polar and Wikipedia:Polar curve (aviation) for example. These curves are not on a polar coordinate system. Why are they called polars?
14 CFR 61.55 says: ... (d) A person may receive a second-in-command pilot type rating for an aircraft after satisfactorily completing the second-in-command familiarization training requirements under paragraph (b) of this section in that type of aircraft provided the training was completed within the 12 calendar months before the month of application for the SIC pilot type rating. The person must comply with the following application and pilot certification procedures: ... (6) The applicant must appear in person at a FAA Flight Standards District Office
I have heard and read many times that for "heavy aircraft", they use a standard rate of turn which is 1.5° per second (4 minute turn), but I have never found an official source which addresses this. Although... I'm actually not even sure where the normal 3° per second (2 minute) standard rate turn is defined either. The wikipedia entry on ROT (Aviation) says: Light aircraft are equipped with 2-minute turn indicators while heavy aircraft are equipped with 4-minute turn indicators. I don't see why "heavy" would have anything to with turning rate, but airspeed certainly does. So, I'm