[Milsurplus] Interesting findings on post-WWII aircraft VHF (Long)

Tue, 19 Mar 2002 19:43:39 -0700

trouble found.... short between the headsets.
----- Original Message ----- 
From: "Todd Bigelow - PS" <[email protected]>
To: <[email protected]>; <[email protected]>
Sent: Tuesday, March 19, 2002 12:06 PM
Subject: [Milsurplus] Interesting findings on post-WWII aircraft VHF (Long)


> I've been doing a little research today, including reading some crash
> investigation reports. One of the reoccurring themes seems to be
> unfamiliarity with VHF and/or the inability of the crew to use it
> properly. Of particular note are the following excerpts from a crash
> involving a C-47 into Pike's Peak in October of 1947:
> 
> 
> 13. NARRATION OF EVENTS:   On 14 October 1947 C-47A  No. 42-23503,
> piloted by Maj. Robert R. Oliver, took
> off from Hill Field, Utah at 1431 M for a flight to Lowry Field, Co.  At
> approximately 1659 the copilot contacted Denver
> approach control on VHF for letdown instructions, estimating his
> position as 25 miles north of Denver on the north leg of the
> Denver radio range. At 1608 the C-47 crashed on Pikes Peak. The pilot,
> copilot and two passengers received major injuries.
> Three passengers were killed and/or died from injuries and exposure.
> 
> ........
> 
> F. No malfunctions nor discrepancies of the C-47 had been noted on the
> flight from Des Moines to Hill other than the
> needle-ball being inop.
> 
> G. At 1607 MST, the pilot contacted Sinclair radio and changed his
> flight plan from VFR to IFR. Denver ATC cleared
> the C-47 at 15,000ft to the Henderson fan marker at Denver.
> 
> H. The pilot violated AAF Reg. 60-16, Para. 55, Subsect (2), HQ AAF 28
> Aug 1947 by requesting change of flight plan to IFR and encountering IFR
> conditions with the T/B indicator inop.  This regulation states: "A
> pilot will not fly an aircraft on an instrument or night flight unless
> it meets the following requirements : The pilot's instrument panel
> contains the following in
> operating conditions: (c) Turn and Bank Indicator"
> 
> .......
> 
> M. The pilot, due to the great amount of precipitation static and
> oscillation of the compass needle, was attempting to
> track into Denver range by use of a nose null on the loop position of
> radio compass.
> 
> N. A moment prior to the crash the copilot noticed trees a few hundred
> feet below them. The copilot placed the props in
> high rpm and pushed the throttles full forward. The pilot in an attempt
> to climb, maneuvered the aircraft into an extremely nose
> high attitude. The airspeed dropped to 50 mph and the aircraft mushed or
> stalled into the north-east slope of Pikes Peak.
> 
> .......
> 
> T. Denver has a VHF radio range, but no attempt was made to use it.
> 
> .......
> 
> Under contributing factors, two are radio related:
> 
> 15. CONTRIBUTING CAUSE FACTORS:
> 
>          A. Weather.
> 
>          B. Inability of the pilot to accurately report his actual
> position to Denver Approach Control.
> 
>          C. Poor radio orientation in that the pilot failed to recognize
> passing Denver while tracking on aural null.
> 
>          D. Failure of the pilot to to use all radio equipment available
> 
> Under 'Comments' is where the interesting stuff seems to be with respect
> to VHF and radio compass:
> 
>  b. Using loop position on radio compass due to the precipitation
> static, the pilot did not realize that the null would and
> did pass to the tail of the aircraft as it passed over the Denver range.
> Not realizing that he had passed the cone, it was quite
> natural for the pilot to assume that the station was still ahead of him.
> Had the pilot switched to a wing tip null as he approached
> Denver, he could have definitely identified the station.
> 
>  c. It is believed that the marker beacon was inop. as the pilot could
> not remember it operating on the flight from Des Moines that morning.
> Radio compass had been used from Des Moines to Hill Field and it is
> likely that he would have noticed it operating as there are several fan
> markers and marker beacons along the airway.
> 
>  d. How the pilot could receive the Denver range on loop position as far
> south as Colo. Springs cannot be explained as the investigating officers
> flew over the crash area on a clear day when radio reception was
> excellent. Denver radio range was
> turned on, the radio compass and reception was excellent on "antenna"
> position, fair on "compass" position, but there was no
> reception on "loop" position. The scene of the crash on Pikes Peak is
> appx 65 miles south of Denver. The pilot should have
> known that the volume would build as he approached the range station.
> Actually he would have had to increase the volume
> several times going away from Denver radio if he were receiving Denver
> radio at the time of the crash.
> 
> f. Denver is equipped with a VHF radio range. The C-47 carried ILS
> (ARN-5) equipment. The radio facility chart lists
> all VHF ranges and diagrams of range legs, aural and visual, yet no
> attempt was made to utilize this equipment even though the
> low frequency radio equipment was practically useless because of static.
> It is believed that the pilot was not familiar with the
> operation and procedure for VHF ranges.
> 
> g. A spot check of several pilots revealed that very few are familiar
> with VHF radio ranges and several did not know
> such equipment existed. Since the majority of Air Force aircraft are
> equipped with ARN-5 equipment, VHF ranges could be
> used during adverse weather conditions.
> 
> Finally under 'Recommendations" is listed this suggestion:
> 
>  b. That the "Operation and Procedures" for VHF ranges be published as a
> special subject by Flying Safety Division, this
> HQ.
> 
> 
> ....wow! Of course, it doesn't state what this 'spot check' consisted
> of, what kind of sampling or how widespread, but it would seem that
> pilots weren't as familiar with VHF as we'd perhaps think? This was late
> 1947, too.
> 
> 
> de Todd/'Boomer'  KA1KAQ
> 
> 
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