Letters

Stopping the propeller

I read with personal interest Barry Schiff's article "Stopping the Propeller" (January Pilot). Years ago I experienced a catastrophic engine failure in a Beech Super Musketeer. Fortunately I was alone at the time and flying in VFR conditions at 5,000 feet agl. After the initial shock, the noise was incredible, the vibration just as bad, and the windshield covered with oil. I followed established handbook procedures, cut off my fuel, set up best glide speed, and determined I had a small private grass strip within gliding distance. I called ATC and told them of my emergency and intentions to attempt a landing at the grass strip. I set my approach up to the 1,400-foot runway, which had a good clear approach. I felt I had everything under control until I had the runway made, dropped full flaps, and slowed to approach speed.

Then the prop stopped. The aircraft accelerated as if I had added power. As a result and in spite of my attempts to both slip and slow the aircraft, I landed longer than I had planned, making the runway but running off the end into standing corn. I now know what an arrested carrier landing must feel like.

My point is that Schiff is 100-percent right about increased glide with a stopped prop, but also to caution that in case of genuine engine failure, the pilot may wish to consider stopping his prop as soon as practical in order to prevent inadvertent stopping when you don't want it — even if below the 5,000 feet recommended by Schiff. I know that I will.

David Boerigter AOPA 492108
Sequim, Washington

In the early 1950s, U.S. Army pilots were taught both fixed and rotary wing flying by Air Force instructors at San Marcos, Texas. I was one of the fixed-wing instructors. Our primary trainer was the L-21, your basic Piper Cub with a bigger engine and flaps. The Army wanted its students to be proficient in every imaginable type of stall, spin, side slip, and dead-stick landing. We saved the dead-stick landings for last, as they were frosting on the cake.

The Army wanted each student to have a total of six; three dual and three solo. We would run the entire class through these in one day, using about 20 airplanes and an auxiliary field with a 2,000-foot runway. We took off, climbed in an orderly pattern to 2,500 feet over the runway, and shut down the engine. Mixture at idle cutoff, magnetos off, and nose as high as it took to let compression stop the prop, just as Barry Schiff described it.

From there on, the only rule was to somehow land between the two colored panels near the end of the runway. Anything the student had been taught so far was legal. An airstart was out of the question. Our airplanes had no batteries and they had to be hand-propped. They also had no radios, so watching out for other airplanes with dead engines was a popular activity.

As Schiff pointed out, it got very quiet. A simple "Boo" in a normal voice would usually make the student jump an inch; more if his belt was loose.

The improvement in glide ratio was spectacular. I didn't know how much or exactly why until I read Schiff's article. Students would invariably overshoot the landing zone, which led to a lot of slips and "S" turns. The student would really concentrate on the landing. In three years, I never saw a bad one.

Once on the runway, the rule was to steer off into the grass to give the airplane behind you a sporting chance. Spare students were positioned along the runway to prop the airplanes so that they could take off and do it again. In those days, that was about as much fun as you could have with your clothes on. In terms of quality training, I would match ours and the proficiency of our students with any in the world.

Do you think it might be a good idea to teach stalls, spins, and dead-stick landings to all students?

Naah. The FAA has already told us that just teaching how to avoid those nasty things is good enough.

Richard H. Wood AOPA 906489
Snohomish, Washington

Building a case?

I read with interest Mark R. Twombly's "Pilotage: Rising from Repose" (January Pilot), especially the reference to E. Glenn Parr, general counsel for Piper Aircraft Corporation. Twombly said Parr believed that for a plaintiff's attorney to build a "convincing case" with reference to possible failure of a part of an aircraft, he must "prove that the part failed prior to impact, and that the failure or defect caused the accident." That is simply incorrect.

Attorneys must only convince a jury, whose members are for the most part uneducated on aircraft systems and parts, that the part was responsible. Plaintiffs' attorneys do not have to prove anything.

Wayne C. Ramsey AOPA 879220
Abilene, Texas

False start

I read " Never Again: False Start" (January Pilot) with great interest. I had a similar experience almost three years ago with my Cessna 172 at an airport in Michigan. It was a cold morning and I remembered reading that hand rotation of the prop prior to start-up would increase the engine life. On my second rotation, the engine unexpectedly started because of a hot magneto. My hand was injured, and the aircraft received substantial damage. Unfortunately, an FAA inspector was nearby, and I received a 30- day suspension of my certificate.

It is unfortunate that I, like so many other pilots, have simply never been trained concerning safety precautions surrounding manual rotation of the propeller. I was caught not only by the moving propeller, but by an unforgiving FAA enforcement action that shared no responsibility for the lack of training that resulted in the incident. The FAA provided absolutely no prior or post-incident training to prevent further accidents like the one mentioned in that article.

John Meehan AOPA 156769
Framington, Massachusetts

The basic premise of "pulling the prop through" to align a Bendix drive is erroneous. Given the 55:1 ratio of most aircraft starters, merely rocking the prop will be sufficient. Experience has taught that this is rarely the problem, however. The problem usually is a stuck drive gear on the starter shaft. This may require moving the prop to gain access, hence the following additional observations.

With any magneto impulse coupling-equipped aircraft, any time the prop is pulled through, the mag is accelerated and may fire. The best way to ensure against inadvertent firing is to confirm that the mags are grounded by going to Off and back to Both at idle speed prior to shutdown. This has been standard operating procedure with the military and commercial operators, probably since the first hot mag with Wilbur Wright or Glenn Curtis.

Regardless of starter conditions, confirming that the mags will indeed shut off is important for safe ground handling, as well as a secondary method of securing the engine in the event of inflight fire, etc.

Secondly, in addition to shutting off both the mags and the master switch, closing the throttle and placing the mixture in Idle Cutoff would have either prevented the aircraft from starting or impeded its traveling very far and is generally standard operating procedure any time the left seat is unoccupied.

Finally, setting the brakes and/or chocking the wheels any time the pilot in command is out of the left seat is also standard operating procedure and described in most pilot operating handbooks. This, coupled with properly setting the throttle and mixture, should have prevented this incident.

L. Mark Fingerlin AOPA 435520
Encinitas, California

The case for Mode C

As a controller at a busy tracon, I am admittedly biased in favor of retaining the Mode C veil or some similar program (" AOPA Action," January Pilot).

A few points to consider. Your article left the impression that no operations except GA are conducted below the floors of Class B airspace. In the San Francisco area alone, there are two international, two military, and six GA airports that lie outside the Class B airspace but within the current Mode C veil. Their arrival and departure flows are all well below, within, and on top of the San Francisco International Class B airspace, yet there is no requirement — nor would it be possible — to contain these operations within the Class B airspace.

By removing the Mode C requirement, the effectiveness of traffic alert and collision avoidance systems is negated. I have seen plenty of TCAS "saves," none of which would have been possible had the aircraft involved not had Mode C.

It is increasingly difficult to issue unknown traffic due to frequency congestion and traffic density. In my opinion, having the Mode C readout allows the controller to call untracked traffic that is a factor, while allowing him or her to disregard traffic that is not a factor based on displayed altitude. We receive complaints and near mid-air collision reports from VFR aircraft that had a close call with unknown and uncalled traffic (makes me wonder whose responsibility it really is for VFR aircraft to avoid other VFR aircraft). Not having Mode C displayed on the radar scope in a high-density airspace environment is going to make it harder to issue timely and effective traffic calls and alerts.

Rick Cote AOPA 929260
San Ramon, California

As an air traffic controller at the Houston Radar Approach Control, I must object to AOPA's proposal to eliminate the Mode C requirement below Class B airspace. Unfortunately, AOPA is missing the point. The purpose of the Mode C requirement is so that controllers can determine quickly if a target is a factor to one of his or her aircraft. Had a Cherokee in Cerritos had an operable transponder with Mode C, a lot of people may still be alive. The Mode C could have alerted the controller of the airspace violation and the conflict that was occurring. Since the Cherokee didn't have an operable transponder, the controller probably assumed that this aircraft was following the rules and was below the then-TCA.

Additionally, we now have a Mode C Intruder alert which sets off an alarm any time the computer recognizes a conflict between a tracked target and an untracked (1200 code) target. Without the altitude readout, this would not be possible. TCAS II works much the same way. An advisory resolving the problem is not possible unless the Mode C is operable. (All air carriers are equipped with TCAS II.)

I understand the high cost of flying because I am an active pilot myself. However, we need to understand that the ATC system is progressing into the twenty-first century. I envision the day when GPS will be required to file IFR. We must progress with the system, and Mode C is a must in busy terminal environments.

Jere G. Gardner AOPA 732468
The Woodlands, Texas

Compass deviation

The private pilot is ultimately responsible for the airworthiness of the airplane he flies, and the answer given to question number five ("Test Pilot," August 1994 Pilot) could get him into trouble with the FAA.

Barry Schiff incorrectly states that there is no limit to the allowable compass deviation. Civil Air Regulation 3.666, which covers most of the light planes flying today, states that the maximum deviation after compensation may not exceed 10 degrees, and in all cases, a suitable calibration shall be provided close to the compass.

Federal Regulation 23.1327, which covers new type certificates, also limits the deviation to 10 degrees, but provides for an exception when highly magnetic equipment is turned on, such as electrically heated windshields. In this case, a special warning placard is required.

Pilots should be properly informed that any aircraft flying normally with a compass deviation greater than 10 degrees is not in an airworthy condition and in violation of the FAA regulations.

Dennis A. Tuck AOPA 110879
Pensacola, Florida

Barry Schiff responds: Thank you for clarifying once and for all the 10- degree deviation limitation. Your efforts in this regard are genuinely appreciated. [ Editor's note: Tuck enclosed a letter from the manager of the FAA's Aircraft Maintenance Division which affirmed the 10-degree maximum deviation and acknowledged that an example in Advisory Circular 43.13-2A might be misleading.]

It boggles the mind, however, that every instrument shop that I called is unaware of this limitation. Most of them referred me to the now- obviously-misleading advisory circular. Furthermore, two airworthiness inspectors from the Los Angeles Flight Standards District Office also confirmed that there was no official limit on deviation. I was even told by the representative of an airframe manufacturer that they were not limited to 10 degrees.

Based on all of this, you can certainly appreciate my skepticism about your claim, which you have proven to be correct. I am sorry, however, that you had to go through all of this trouble to prove your point.

Positioning the lights

Barry Schiff is incorrect in his analysis of the inverted position light problem ("Test Pilot," January _Pilot_). The three position lights (red, green, and white) project light in three non-intersecting arcs, 110 degrees each for the red and green lights and 140 degrees for the aft white light. At no time would you see two position lights except for the cases of exactly nose-on, and exactly 110 degrees aft of the nose-on position. Three position lights are never simultaneously visible, except for perhaps directly above or below. If you see both red and green position lights at the same time, you should consider a collision imminent, whether or not you or the other aircraft is inverted.

Stephen D. Slobin AOPA 633369
Altadena, California

I disagree with Barry Schiff's question regarding position lights. These lights are shielded to be visible from certain sectors and in no instance should you be able to see all three at the same time.

Here is what I tell my students about traffic close to your altitude: If you see a red light, yield (traffic is from your right). Green light: watch for traffic to yield (coming from your left) but be prepared to evade, as others might not be as vigilant as you. White light: yield (you are overtaking). Any time you see both the green and the red light, the traffic is coming toward you; that white light in the middle is the guy's nose-mounted landing light. Yield.

Roy Stefanussen AOPA 873616
Bellevue, Kentucky

Come on, Barry, you need to do the next night walkaround and give your first or second officer a break. You can't see either the port or starboard navigation lights from the back of an airplane, inverted or otherwise. They are deliberately shaded to prevent this. There is only one answer to your scenario: An aircraft is coming directly at you, with its landing light on.

Stephen J. McNamara AOPA 931242
Little Rock, Arkansas

Barry Schiff responds: Creating "Test Pilot" each month is very challenging, and because of my enthusiasm to produce an unusual, entertaining, and educational quiz, it is possible to get too clever. Such was the case regarding the question about position lights. I simply got carried away with the concept of the question without taking the time to realize that it is not possible to see the wing tip lights of another airplane from directly behind.

You are all quite accurate in your criticisms of both the question and the answer.

We welcome your comments. Address your letters to: Editor, AOPA Pilot, 421 Aviation Way, Frederick, Maryland 21701. Include your full name, address, and AOPA number on all correspondence. Letters will be edited for style and length.