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    Re: Bygrave and Chichester
    From: Greg R_
    Date: 2009 Aug 2, 19:27 -0700

    Gary LaPook wrote:
    > A problem unique to the 336/337 was that sometimes the rear engine
    > would quit while waiting for takeoff and the pilot wouldn't k know it and
    > so would attempt to takeoff with only the forward engine which resulted
    > in takeoff accidents. The proper technique is to advance the throttle of
    > the rear engine prior to advancing the throttle of the front engine so
    > that this problem could be identified.
    Weren't some models equipped with a "Low Thrust Warning" light? Don't know
    if that was required by an AD (Airworthiness Directive, for the non-pilot
    audience) or something Cessna added, but seems like I remember seeing that
    in at least one Skymaster.
    ----- Original Message ----- 
    From: Gary LaPook
    To: NavList@fer3.com
    Sent: Sunday, August 02, 2009 4:03 PM
    Subject: [NavList 9303] Re: Bygrave and Chichester
    Cessna 336 and 337 planes are centerline thrust so do not have the yawing
    problem when one engine fails but do have the severe reduction in climb
     in common with other twins. It may come as a surprise but twins weighing up
    to 6,000 pounds that have a stall speed of not more than 61 knots are not
    required to be able to climb on one engine. FAR 23.67 (a)(2) only requires
    that " the steady gradient of climb or descent" must be determined. An
    example of this is the Piper Apache which had a pretty good decent rate on
    one engine. I am not sure that the 336 would climb on one engine since it
    had fixed gear. The 337 would climb on one but with just the minimum rate
    required by regulations. Federal Aviation Regulation (FAR) 23.67(a)(1) only
    requires a 1.5% gradient on one engine. I don't have my 337 manual with me
    (I am in Paris) but I think its single engine best rate of climb speed
    (Vyse) was about 90 knots or 9114 feet per minute. 1.5% of this is only a
    136 feet per minute rate of climb. I had a case in which the heirs of a
    pilot who did a touch and go at a one way airport in Paradise California
    claimed that he had suffered an engine failure caused by my mechanic
    client's negligence in installing a defective electric boost pump on the
    rear engine.(Never mind that in a 337 the boost pump is not supposed to be
    turned on for landing.) Of course, everyone knows you don't do a touch and
    go on a one way airport since the terrain rises faster than planes can
    climb. (A one way runway is one on the side of a steep mountain, you land
    uphill and take off downhill towards lower terrain. You don't do a touch and
    go, momentarily landing and then taking off again, in the direction of
    rising terrain.) We were able to prove by witness testimony of the point
    where he started his takeoff again to the point where he hit the tree that
    it was impossible for the plane to climb at that gradient on only one
    engine, both engines had to have been operating to get to the point, near
    the top of the tree, where the plane impacted.
    A problem unique to the 336/337 was that sometimes the rear engine would
    quit while waiting for takeoff and the pilot wouldn't k know it and so would
    attempt to takeoff with only the forward engine which resulted in takeoff
    accidents. The proper technique is to advance the throttle of the rear
    engine prior to advancing the throttle of the front engine so that this
    problem could be identified.
    1.1 Critical engine means the engine whose failure would most adversely
    affect the performance or handling qualities of an aircraft.
    Title 14: Aeronautics and Space
    Subpart B-Flight
    Browse Previous | Browse Next
    � 23.67   Climb: One engine inoperative.
    (a) For normal, utility, and acrobatic category reciprocating engine-powered
    airplanes of 6,000 pounds or less maximum weight, the following apply:
    (1) Except for those airplanes that meet the requirements prescribed in
    �23.562(d), each airplane with a VSOof more than 61 knots must be able to
    maintain a steady climb gradient of at least 1.5 percent at a pressure
    altitude of 5,000 feet with the-
    (i) Critical engine inoperative and its propeller in the minimum drag
    (ii) Remaining engine(s) at not more than maximum continuous power;
    (iii) Landing gear retracted;
    (iv) Wing flaps retracted; and
    (v) Climb speed not less than 1.2 VS1.
    (2) For each airplane that meets the requirements prescribed in �23.562(d),
    or that has a VSOof 61 knots or less, the steady gradient of climb or
    descent at a pressure altitude of 5,000 feet must be determined with the-
    (i) Critical engine inoperative and its propeller in the minimum drag
    (ii) Remaining engine(s) at not more than maximum continuous power;
    (iii) Landing gear retracted;
    (iv) Wing flaps retracted; and
    (v) Climb speed not less than 1.2VS1.
    Tom Sult wrote:
    I agree with what you have said but the crash data for 336/337 is no
    better than other twins.
    Thomas A. Sult, MD
    IntegraCare Clinic
    On Aug 2, 2009, at 3:58 PM, Greg R. wrote:
    Not to speak for Gary, but the pusher/puller configuration has
    what's called
    "centerline thrust" - i.e. if you lose an engine, the thrust vector
    stays on
    the centerline - theoretically making the engine-out procedure
    easier to
    handle (ditto for a single-engine, though the engine-out procedure
    is a lot
    more cut-and-dried...  ;-)).
    Wing-mounted twins have a more-complicated engine-out procedure -
    not only
    identifying the dead engine, securing/feathering it (also true of
    centerline-mounted engine configs), but also maintaining a slight
    bank angle
    to compensate for the thrust imbalance caused by the dead engine.
    Not sure if the Vmc (minimum-controllable velocity) restrictions
    would apply
    to A/C with centerline-mounted engines, that's probably a question
    for Gary.
    ----- Original Message -----
    From: "Greg Rudzinski" 
    To: "NavList" 
    Sent: Sunday, August 02, 2009 12:16 PM
    Subject: [NavList 9297] Re: Bygrave and Chichester
    How would the Cessna 336/337 perform if one engine fails? Is there an
    advantage to a pusher puller configuration over a single or wing
    mounted twins?
    On Aug 2, 11:18 am, Gary LaPook  wrote:
    Well, I would agree with you Douglas, as judged from our
    perspective in
    2009, that Chichester may have been "reckless." But as judged from
    standards of aviation pioneers almost 80 years ago, I prefer the word
    "bold." If you look at early pioneering efforts, Lindberg, Perry, Sir
    John Franklin, Columbus etc., they all appear reckless as viewed
    our prism of time. But that is what pioneering is all about, taking
    Regarding you preference for twin engine flying, the accident
    show that they are more dangerous than singles, pretty
    counter-intuitive. Flying a twin when both engines are operating is
    like flying a single, it only gets interesting when one quits. Then
    pilot must deal with a greatly reduced performance envelope and
    asymmetric thrust causing control difficulties. If the pilot
    doesn't do
    everything exactly right he ends up crashing and the crash happens
    at a
    higher speed than would have occurred in a single. By US
    standards (I expect they are similar in Britain) a single must have a
    stall speed below 60 knots while a twin can have a much higher speed.
    This means that a pilot trying to crash land a twin must fly above
    stall speed resulting in a higher impact speed and much more kinetic
    energy to dissipate (varies with velocity squared), can we say "torn
    aluminum" and "mangled bodies?" I've litigated airplane crashes for
    last twenty years and I have seen my share of bent aluminum and
    photos. (BTW, a Cessna 310 Twin fits in a box on a standard pallet,
    about five feet square and three feet deep after it impacts the dirt.
    Airplanes are mostly air surrounded by an aluminum skin, just like an
    empty beer can and they squish just like a beer can..)
    After the loss of one engine the airplane has little or no climb
    capability. It will only climb or maintain altitude if the pilot does
    everything right. If he doesn't get rid or the drag form the flaps,
    landing gear and the windmilling propeller immediately then he is
    I'll give you some examples. About seven years ago a Cessna 310 was
    taking off from Laverne airport just northeast of Los Angeles on July
    4, 2002, Independence Day. One engine quit right after takeoff and
    pilot did not do everything right and the plane crashed on top of a
    bunch of picnickers celebrating Independence Day in the park near the
    airport resulting in the deaths of the two occupants of the plane,
    deaths of the picnickers and severe injuries for nine other people on
    the ground. See the accident report at:
    The left propeller control was found "one inch aft." In order to
    the propeller it is necessary to pull the prop control all the way
    about eight inches. Since the pilot did not move the prop control all
    the way aft the prop did not feather and the plane could not maintain
    altitude with the left engine windmilling creating a lot of drag. It
    turned out that the pilot had done exactly as he had been instructed.
    His instructor's technique for practicing engine out emergencies
    for the student pilot to just pull the prop control back one inch to
    demonstrate that he had identified the failed engine and that he
    have feathered the prop in a real emergency. But in a high stress
    situation people do what they have practiced so four dead people,
    including two little children, and nine serous injuries.
    Another case I worked on involved a Piper Navaho hauling sight seers
    around Hawaii. One engine packed it in and because the mechanic had
    used the proper method to adjust the wastegate controller on the
    engine, the remaining engine was not developing full power so the
    airplane could not maintain altitude on the one engine. So even
    the pilot was doing everything right he still had to ditch in the sea
    near Hilo and one little old lady, celebrating her fortieth wedding
    anniversary, rode the plane to the bottom of the sea. See report
    Another case I worked on involved a Twin Otter powered by two Pratt &
    Whitney turboprop engines. The underground fuel tank from which the
    airplane had just been refueled was contaminated with water (it
    like mud) and one engine stopped right after the nose was raised
    due to
    ingesting the water. The pilot then did everything wrong and
    the wrong engine, shutting down the one operating engine. This
    in 16 deaths of the occupants.
    Having two engines gives one the sense that he has redundant
    systems and
    that it is unlikely to have two reliable systems fail at the same
    So, if an engine should fail once every 5,000 hours then the chance
    two such engines failing at the same time should be only once every
    25,000,000 (5,000 times 5,000) hours. But that assumes that the two
    systems are completely independent from each other which is rarely
    case. First, obviously, both engines are being operated by the same
    pilot and any error on his part can result in the loss of both
    Both engines received the same fuel so if one tank has contaminated
    they both do. They were refueled at the same time so if the pilot
    one out of fuel then the other will follow moments later. The same
    mechanic worked on both engine and if he screwed up one then he
    screwed up the other one too. I remember watching a Cessna 310 take
    from Chicago Midway airport one day. Right after takeoff one engine
    failed and the pilot was able to bring it around and land safely. The
    plane taxied up to my hangar with one prop stopped and my friend Bill
    jumped out and walked right past me. I asked him, as he passed,
    what had
    happened and he said he couldn't stop to talk as he had to "go and
    out his shorts." I don't think he was talking figuratively since he
    immediately into the men's room. The next day when I saw him I asked
    again and he said he was doing a test flight after the mechanic had
    adjusted the propeller governor and right after takeoff that one
    propeller had gone into feather uncommanded which resulted in the
    of power from that engine. As he was bringing the plane around to
    he said that all he could think about was that the mechanic had just
    adjusted _both_ propeller governors and he was waiting for the
    other one
    to go into feather too.
    In the case of over water ferry flights on which the plane is heavily
    overloaded with fuel, the single engine ceiling may be below sea
    This means with such a heavy load that the plane cannot maintain
    altitude if just one engine fails and a ditching is inevitable. In
    case a twin is quite a bit less safe than a single since with two
    engines you have twice the probability of an engine failure, 2 per
    hours using my prior example.
    douglas.de...@btopenworld.com wrote:
    My interest in the Bygrave helical slide rule too Gary, was
    when I read Chichester's book 'The Lonely Sea and the Sky' many
    years ago.
    I have been hoping ever since to find one, perhaps one of them would
    turn up in an antique shop or 'car boot sale', but now realise that
    dream is far from ever becoming a reality.
    It is very strange that they are now so incredibly rare
    considering they
    must have been made in reasonably large numbers from the early
    1920's up to
    the mid 1930's, and were also an official piece of navigating 'kit'
    aircraft navigators in that period for the RAF, so must have been
    made in
    fairly large numbers rather than just a relatively few for
    purposes. They were also available to buy privately. So what
    happened to
    them all? It's most odd.
    Even the most arcane scientific apparatus and instruments are
    preserved or survive in private hands to be sold on or given away to
    rather than just binned.
    Are all those RAF Bygrave slide rules still locked away in some old,
    musty, forgotten RAF or government store at the back of dusty shelves
    awaiting some storekeeper to find them and be told to put them in an
    of ex-government surplus. (Still dreaming you see !).
    Whilst the skill and amazing endeavour of what Chichester achieved
    not to be denied an any way, (and you have now confirmed by your own
    practical flying test in a Tiger Moth); which was immediately
    apparent to me
    when I read of the exploit, and it has continued to amaze me still -
    what he wrote I was also filled with the astonishment and feelings
    Chichester was idiotically reckless in what he did,..(I think) to
    the point
    of insanity.
    Given that he writes in a style which is deliberately meant to
    make his
    story not just interesting but no doubt boost his (Chichester's)
    and sales of the book, and hopefully have the reader clutching the
    book with
    white knuckles in anticipation of events unfolding; nevertheless, he
    a devil-may-care attitude of quite serious stupidity and ignores
    issues of
    high importance which any right-thinking person would not consider
    reasonable, and certainly not anyone who knows anything about flying
    and the
    consequences involved in flying solo in a single engined aitrcraft
    with a
    'dodgy' engine over large stretches of water.
    I had a personal friend who taught me to fly, he was the Chief
    Instructor at Bembridge flying school, and who very nearly lost his
    when the donkey of the Cessna 150 stopped en route, mid - Solent, as
    he was
    flying back to Bembridge from Goodwood, (The Solent is the sea -
    only four
    miles of water between the Isle of Wight and the mainland) -and after
    turning downwind towards the mainland to maximise his ground
    traverse, he
    did not make it and was...
    read more �
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