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cfi

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Everything posted by cfi

  1. Most of this has been covered by other posters, but to summarize... A precautionary landing sits between a normal landing and a forced landing (see the references posted by smac). It is absolutely an emergency situation. Even if the pilot does not formally declare an emergency to ATC (air traffic control) on the radio, ATC treats it as an emergency. If you make a precautionary landing at a towered airport (one with an operating control tower), the emergency vehicles will roll to meet the airplane and will be prepared for the worst possible outcome. Shutting down an engine in flight, and "feathering" the propeller, is absolutely an emergency. On a twin-engine airplane, losing one engine results in losing approximately 80% of your ability to climb (explaining why requires physics equations). Depending on airplane weight and engine power, one engine may not even maintain altitude. Lose an engine, you are going down. It's just a question of where, and whether or not you want it to be a "precautionary landing" or a crash. An engine with a broken or separated cylinder is definitely "rough running", fire or not. It would be entirely appropriate for a pilot with a rough-running engine to declare and emergency with ATC. The pitch of the propeller (the angle at which it "bites" into the air) is controlled by pressurized oil from the engine to the propeller hub (the cylinder to which the blades are attached). "Feathering" the propeller means turning it flat into the wind so it offers minimal drag, which helps the airplane stay aloft if that engine is shut down. This can be done intentionally from the cockpit, which causes the hub to "dump" the pressurized oil back into the engine. If the engine is broken and "dumping" oil overboard, it can no longer supply pressurized oil to the hub, and the propeller will feather on its own (via springs and counterweights normally opposed by the oil pressure). Two possible meanings of "dump oil" that can be confused, one is intentional, the other is not. And since someone brought it up, my "credentials" (without sacrificing privacy): Commercial Pilot and Certificated Flight Instructor ("cfi"). 35 years experience. Ratings include single-engine land, single-engine sea, multiengine land, multiengine sea, and instrument airplane. Chief Flight Instructor for a large flight school for about 10 years (responsible for overseeing safety, including the reporting of incidents to the FAA and NTSB). I volunteer with the FAA Safety Team and give public presentations on aviation safety. I own and maintain a twin-engine airplane (money pit!) that I use for training future airline pilots, and a single-engine airplane I fly for fun. All this is in addition to my full-time job as an engineer who designs certified systems for transport category (jet) aircraft.
  2. Depends on how the interior is set up. The engines are on either side of the first row of seats (pilot/co-pilot). There are either two or three rows of seats behind that. In a typical setup, the seats all face forward, and everyone can see everything. In a "luxury" setup, the front windows are mostly blocked by dividers and there may be a cockpit curtain that would be closed, blocking all view out the front, and there may also be curtains on the side windows. In this setup, the two front passenger seats face backwards, allowing fold-down tables to be set up between them. The rear-facing passengers would have trouble seeing forward even if the curtains are open. My guess is that a low-cost commuter airline would use the less expensive setup, with everyone facing forward, and nothing blocking any of the windows. A charter service might use the more expensive luxury setup. These photos are actual PA-31 Navajo airplanes, with the camera mid-cabin facing forward.
  3. On an air-cooled engine, the cylinders are attached with studs (bolts without heads) threaded into the crank case and secured with nuts. In the photo below, the studs and nuts are black, around the circular base of each of the four cylinders. The photo is looking at the front of the engine towards the rear; the propeller would be attached to the large silver shaft in the lower left. If enough of the studs break ("shear" is one way a stud or bolt could break), the cylinder will no longer be sealed against the crank case, and the engine oil will escape. This will cause a rough running engine, which will get worse as the oil continues to drain and the engine starts grinding itself up. Eventually it will seize and stop entirely. If a few more studs break, the cylinder will shift and the piston will no longer move freely. With the piston moving up and down in the cylinder 80-90 times per second, the resistance will likely cause the cylinder to split open or break off the engine. This will allow the burning fuel/air mixture to escape. A loud bang and fireball, followed by severe vibrations as the engine is still trying to move the piston back and forth inside the misaligned or detached cylinder. If the fuel supply and ignition are not cut off, the spark plugs will continue to ignite the fuel, which will escape and possibly ignite other things in the the engine bay. In addition to the fire, the violently shaking engine could break free from the airplane, and possibly take part of the wing with it. Thus the urgent need to get everything shut down and stopped quickly. If the fire spread outside the engine, getting on the ground quickly is even more urgent. The second photo below shows a cylinder that split open in flight. The thin silver tubes are the fuel lines, taking fuel from the round manifold on the right to each cylinder on the left. The spark plugs are attached to the blue wires, and enter the cylinder right next to the fuel lines. Whatever the exact details, this would definitely be terrifying -- both the initial event, and the emergency descent and landing. I never thought I'd be explaining airplanes on a church message board, but someone said "airplane." You can guess who one of my favorite General Conference speakers is... 🤔
  4. Under the current rules for notifying the NTSB, found in 49 CFR 850.5, the incident described by Pres. Nelson does not require notification (or investigation). Rules in effect back then were likely similar. Commercial operators also have additional rules, call "Ops Specs", which may include the reporting of incidents and accidents, but these are specific to each operator. I have no way of finding this for a defunct operator from the 1970s, but this is likely why there was any report to the CAB at all. 49 CFR 830.5 Helix did post a link to the standard reference on airplane emergency procedures, the FAA's Airplane Flying Handbook. It covers general procedures not specific to any airplane. Airplane Flying Handbook chapter 17 Government-written texts are often insomnia-inducing, so here's an easier-to-read article on the subject: How to Fly an Emergency Descent Each make & model of airplane has its own specific procedures, spelled out in the checklists contained in the Pilot's Operating Handbook. A quick google search failed to find one for the PA-31, but here's the checklist for my airplane. Note that it lists only airplane-specific details. It is assumed the pilot knows the general procedure (i.e. this checklist gives specific configuration items, but does not mention a spiraling descent, because the pilot should already know that).
  5. Two possibilities come to mind reading your story. One (more likely), the pilot was mentally "behind" the airplane and allowed it to get away from him. He allowed the airplane to get too slow on approach, allowing the wings to "stall," causing the airplane to drop rapidly towards the ground. He tried to recover by adding power, but the airplane hit the ground in the process. It bounced back into the air before it had enough speed for stable flight, resulting in wild gyrations as the pilot tried to regain control, which he finally did. Or two, the airplane encountered vertical windshear that rapidly pushed the airplane towards the ground, with a similar recovery attempt and premature bounce back into the air. Either way, your story is more scary than Pres. Nelson's 😲
  6. I am a pilot and flight instructor with 35 years experience. The Piper PA-31 Navajo is a small twin-engine airplane that carries 6 to 8 people including the pilot. The interior is about the size of a small mini-van. Everyone can see the pilot up front and both engines out the windows. The engines are piston engines, not jets. One engine experienced a cylinder failure. On an air-cooled engine, the cylinders are individual assemblies attached to the crank case (very different from a car engine, where everything is buried inside the engine block). If one fails, it can be quite spectacular as the burning fuel/air mixture escapes and the now-unbalanced engine begins shaking violently. Standard procedure: 1) Shut down the bad engine and feather the propeller (turn the blades into the wind to minimize drag). This causes the propeller to stop spinning. The fuel would also be shut off so as to not feed the fire. 2) Descend as quickly as possible to land, even if not at an airport. Better to land in a field than to burn up in the air. The emergency descent involves pulling the throttle on the good engine back to idle (it is NOT shut down), banking the airplane, and pushing the nose down to get as much airspeed as possible. This creates a spiraling descent. (Descending rapidly in a straight line "unloads" the wings, which could cause severe airframe damage if the wings were suddenly "loaded" by turbulence.) This rapid descent also has the benefit of possibly "blowing out" the fire (much like blowing out a candle). 3) Near the ground, roll out of the dive, level out, let the airplane slow down, and bring the power back up on the good engine to keep the airplane flying. If still burning, land wherever possible and evacuate. If the fire is out, proceed to the nearest airport or suitable landing site. The passengers were never about to die, and there was no miracle recovery from the dive. The pilot knew the outcome from the start. Every multiengine pilot is trained to do this. It's published in countless manuals and training materials. I teach this to my multiengine students frequently. The "emergency descent" is a wild ride as the view out the front window looks like you're pointing straight towards the ground (really only about 30* nose down) and the airspeed shoots up into the "yellow arc" on the airspeed indicator (the "caution zone"). But Pres. Nelson wasn't describing what the pilot was doing, he was describing the emotional perception of the naive passengers, whose reaction apparently ranged from terrified to hysterical. The passengers perceived that one engine had exploded, that the other had been shut down, that the airplane was falling uncontrolled out of the sky, that they were going to die, and that they miraculously recovered. No embellishment, just a story about an emotional experience. If I put a passenger in the back of an airplane and demonstrated an emergency descent without telling them, they would probably have a similar reaction, even without the spectacular engine failure. As a side note, for an incident like this, the CAB / FAA / NTSB would not have sent anyone to investigate. They would have merely gathered information from the mechanic who inspected the airplane, the pilot, and the owner/operator. Engine failures in flight, with no injuries or airframe damage, are a dime a dozen and not worth investigating.
  7. If a person's membership is terminated, their record is removed from the active rolls, but the record is still retained. Nothing is ever deleted. This is, among other things, to facilitate former members who wish to return, and it prevents known abusers ("annotated" record) from returning with a clean slate. Termination of membership does nullify all ordinances and the blessings thereof, but children always retain the blessings of parent/child sealings regardless of their parent(s) status. If a person whose membership was terminated returns to the church, they must be baptized and confirmed. Everything else -- priesthood, temple ordinances, and all sealings -- are restored with a single ordinance called "Restoration of Blessings." That one ordinance covers everything post-confirmation. More details are in the General Handbook. Search for "Restoration of Blessings." There's a whole section on returning to the church.
  8. My grandfather, who is a Sealer, explains it this way: The Handbook states "Children who are born after their mother has been sealed to a husband in a temple are born in the covenant of that sealing." But it then gives one very specific example, which leaves people wondering about other situations. More generally, "born in the covenant" means the covenant of the mother's sealing. If a mother with a valid sealing (not canceled or revoked) gives birth, the child is sealed to her and the man to whom she is sealed at that time, who may or may not be the biological father and/or the mother's current legal husband. This is (one reason) why a living woman can be sealed to only one man.
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