When did "the six-pack" become standard?

[Stephan Wilkinson]

When did the "six-pack" of instrument-flying gauges become standard on World War II aircraft panels, obviating the need to fly what my long-ago first instrument instructor used to call "speedle, needle, airball"?

[Tiger Tim]

I'm guessing post-WWII to start since this B-66 still has instruments mounted wherever they would fit:
viewtopic.php?f=3&t=57841

[Invader26]

Early history

In 1929, Jimmy Doolittle became the first pilot to take off, fly and land an airplane using instruments alone, without a view outside the cockpit. In 1937 the British Royal Air Force (RAF) chose a set of six essential flight instruments[3] which would remain the standard panel used for flying in instrument meteorological conditions (IMC) for the next 20 years.
They were:
altimeter (feet)
airspeed indicator (knots)
turn and bank indicator (turn direction and coordination)
vertical speed indicator (feet per minute)
artificial horizon (attitude indication)
directional gyro / heading indicator (degrees)
This panel arrangement was incorporated into some RAF aircraft, the 4-engined Avro Lancaster heavy bomber, but not the light single-engined Tiger Moth trainer, and minimized the type-conversion difficulties associated with blind flying, since a pilot trained on one aircraft could quickly become accustomed to any other if the instruments were identical.
This basic six set, also known as a "six pack", was also adopted by commercial aviation. After the Second World War the arrangement was changed to: (top row) airspeed, artificial horizon, altimeter, (bottom row) turn and bank indicator, heading indicator, vertical speed.
Further development[edit]
Of the old basic six instruments, the turn and bank indicator is now obsolete. The instrument was included, but it was of little use in the first generation of jet airliners. It was removed from many aircraft prior to glass cockpits becoming available. With an improved artificial horizon, including gyros and flight directors, the turn and bank indicator became needless except when performing certain types of aerobatics (which would not be intentionally performed in IMC to begin with). But the other five flight instruments, sometimes known as "the big five", are still included in all cockpits. The way of displaying them has changed over time, though. In glass cockpits the flight instruments are shown on monitors. But the display is not shown by numbers, but as images of analog instruments. The artificial horizon is given a central place in the monitor, with a heading indicator just below (usually this is displayed only as a part of the compass). The indicated airspeed, altimeter, and vertical speed indicator are displayed as columns with the indicated airspeed and altitude to the right of the horizon and the vertical speed to the left in the same pattern as in most older style "clock cockpits".
Different significance and some other instrumentation
In good weather a pilot can fly by looking out the window. However, when flying in cloud at least one gyroscopic instrument is necessary to orientate the aircraft, being either a artificial horizo, turn and slip or gyro compass.
The vertical speed indicator, or VSI, is more of "a good help" than absolutely essential. On jet aircraft it displays the vertical speed in thousands of feet per minute, usually in the range -6 to +6. The gyrocompass can be used for navigation, but it is indeed a flight instrument as well. It is needed to control the adjustment of the heading, to be the same as the heading of the landing runway. Indicated airspeed, or IAS, is the second most important instrument and indicates the airspeed very accurately in the range of 45 to 250 knots. At higher altitude a MACH-meter is used instead, to prevent the aircraft from overspeed. An instrument called true airspeed, or TAS, exists on some aircraft. TAS shows airspeed in knots in the range from 200 knots and higher (It is like the Mach-meter: not really a flight instrument). The altimeter displays the altitude in feet, but must be corrected to local air pressure at the landing airport. The altimeter may be adjusted to show an altitude of zero feet on the runway, but far more common is to adjust the altimeter to show the actual altitude when the aircraft has landed. In the latter case pilots must keep the runway elevation in mind. However a radio altimeter (displaying the height above the ground if lower than around 2000–2500 feet) has been standard for decades. This instrument is however not among the "big five", but must still be considered as a flight instrument.

[Stephan Wilkinson]

Okay, what I'm basically trying to find out is whether the pilots flying C-47s, C-46s, C-87s and C-54s on the World War II Hump route across the Himalayan foothills, much of which was done in IMC, were likely to have had a full six-pack flight-instrument array, or were they basically flying needle/ball/airspeed?

It's of interest to me because many of them seemed to have a very hard time doing it, and I never found modern steam-gauge instrument flying to be all that difficult.

[Jimmy mcgee]

Okay, what I'm basically trying to find out is whether the pilots flying C-47s, C-46s, C-87s and C-54s on the World War II Hump route across the Himalayan foothills, much of which was done in IMC, were likely to have had a full six-pack flight-instrument array, or were they basically flying needle/ball/airspeed?

It's of interest to me because many of them seemed to have a very hard time doing it, and I never found modern steam-gauge instrument flying to be all that difficult.

Could it be due to the majority of these pilots having very little total time and even less on instruments. Also could the quality of the instruments be as good as today? or at least their maintenence. If you read the current day accident reports, many accidents occur with low time pilots, low time instrument experience.

[Ken]

Okay, what I'm basically trying to find out is whether the pilots flying C-47s, C-46s, C-87s and C-54s on the World War II Hump route across the Himalayan foothills, much of which was done in IMC, were likely to have had a full six-pack flight-instrument array, or were they basically flying needle/ball/airspeed?

Most WWII a/c were in the middle ground, where the instruments that were to make up the 6-pack were present, but not in the 6-pack configuration. Also, the first attitude indicators were poor and many ignored them in favor of needle & ball.

Ken

[Stephan Wilkinson]

Thanks, Ken. That sounds about right.