ACUFO:

ACUFO is my comprehensive catalog of cases of encounters between aircraft and UFOs, whether they are “explained” or “unexplained”.

The ACUFO catalog is made of case files with a case number, summary, quantitative information (date, location, number of witnesses...), classifications, all sources mentioning the case with their references, a discussion of the case in order to evaluate its causes, and a history of the changes made to the file.

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Billings, Montana, USA, on August 13, 1947:

Case number:

ACUFO-1947-08-14-BILLINGS-1

Summary:

The newspaper The Bismarck Tribune, of Bismarck, North Dakota, USA, reported on page 1 for August 14, 1947, that Herman Lerdahl, captain of the Northwest Airlines plane which passed through Bismarck at 6:50 p.m. on August 13, 1947, said he saw a "flying disc or other unidentified object" over Billings, Montana, at 3 p.m. on August 13, 1947.

The newspaper tells that Lerdahl, with Northwest Airlines Captains Walker and Engebretsen, were watching a skywriter, working at an elevation of about 10,000 feet when one noticed "an object" apparently beyond the sky-writing. The best identification they could give it was "an object in the sky."

It moved slowly toward the west as they watched. A call to the Billings weather bureau brought the information that the last weather balloon released by it had disappeared to the eastward.

Lehrdahl was quoted saying: "I don't know what it was, but I do know it was something. All of us saw it."

The Associated Press wrote a very brief summary of this report; which appeared in other newspaper on August 15, 1947.

Data:

Temporal data:

Date:	August 13, 1947
Time:	03:00 p.m.
Duration:	?
First known report date:	August 14, 1947
Reporting delay:	1 day.

Geographical data:

Country:	USA
State/Department:	Montana
City or place:	Billings

Witnesses data:

Number of alleged witnesses:	3
Number of known witnesses:	1
Number of named witnesses:	3

Ufology data:

Reporting channel:	The Press.
Visibility conditions:	Day.
UFO observed:	Yes.
UFO arrival observed:	?
UFO departure observed:	?
UFO action:	?
Witnesses action:	Observed.
Photographs:	No.
Sketch(s) by witness(es):	No.
Sketch(es) approved by witness(es):	No.
Witness(es) feelings:	?
Witnesses interpretation:	Object in the sky.

Classifications:

Sensors:	[X] Visual: Several. [ ] Airborne radar: N/A. [ ] Directional ground radar: [ ] Height finder ground radar: [ ] Photo: [ ] Film/video: [ ] EM Effects: [ ] Failures: [ ] Damages:
Hynek:	DD
Armed / unarmed:	Unarmed.
Reliability 1-3:	2
Strangeness 1-3:	1
ACUFO:	Totally insufficient information.

Sources:

[Ref. bit1:] NEWSPAPER "THE BISMARCK TRIBUNE":

Airline Pilot Spots 'Disc' on Way Here

Herman Lerdahl captain of the Northwest Airlines plane which passed through Bismarck at 6:50 p.m., Wednesday, said he saw a "flying disc or other unidentified object" over Billings, Mont., at 3 p.m., Wednesday.

Lerdahl, with Northwest Captains Walker and Engebretsen, were watching a skywriter, working at an elevation of about 10,000 feet when one noticed "an object" apparently beyond the sky-writing. The best identification they could give it was "an object in the sky."

It moved slowly toward the west as they watched. A call to the Billings weather bureau brought the information that the last weather balloon released by it had disappeared to the eastward.

"I don't know what it was," said Lerdahl, "but I do know it was something. All of us saw it."

[Ref. gfh1:] NEWSPAPER "THE GRAND FORKS HERALD":

Those "Flying Discs" Are Back

BISMARCK - (AP) - Those "flying discs" are back again.

Herman Lerdahl, captain of a Northwest Airlines plane which passed through here early Wednesday night, said he saw a "flying disc or other unidentified object" over Billings, Mont., at 3 p.m. Wednesday.

"I don't know what it was," said Lerdahl, "but I do know it was something. All of us saw it." The best identification he could give was that it was "an object in the sky."

[Ref. rcj1:] NEWSPAPER "THE RAPID CITY JOURNAL":

Pilot Sees 'Flying Disc' Near Billings

Bismarck, N. D., Aug. 15 - (AP) - Those "flying discs" are back again. Herman Lerdahl, captain of a Northwest Airlines plane which passed through here last night, said he saw a "flying disc or other unidentified object" over Billings, Mont. at 3 p. m. yesterday.

"I don't know what it was," Lerdahl said, "but I do know it was something. All of us saw it." The best identification he could give was that it was "an object in the sky."

Aircraft information:

We know that the aircraft was a Northwest Airlines (NWA) airliner with a crew of three men.

In 1947, the company operated DC-3s and DC-4s for long-haul routes. In this case, it was probably a DC-3.

The DC-3 is the civilian airliner version of the famous Douglas C-47 "Skytrain" military transport aircraft. The photograph below shows a United Airlines DC-3; some of these aircraft were still taking part in air shows in the 2000s.

The DC-3 has a cruising speed of 207 mph (333 km/h), a capacity of 21 to 32 passengers or 6,000 pounds (2,700 kg) of cargo, and a range of 1,500 miles (2,400 km); it can operate from short runways.

Discussion:

The information is too meager to allow for a sound evaluation of this sighting.

Evaluation:

Totally insufficient information.

Sources references:

* = Source is available to me.
? = Source I am told about but could not get so far. Help needed.

[bit1] * Article in the newspaper The Bismarck Tribune, Bismarck, North Dakota, USA, page 1, August 14, 1947.
[gfh1] * Article in the newspaper The Grand Forks Herald, Grand Forks, North Dakota, USA, page 3, August 15, 1947.
[rcj1] * Article in the newspaper The Rapid City Journal, Rapid City, South Dakota, USA, page 5, August 15, 1947.

File history:

Authoring:

Main author:	Patrick Gross
Contributors:	None
Reviewers:	None
Editor:	Patrick Gross

Changes history:

Version:	Create/changed by:	Date:	Description:
0.1	Patrick Gross	June 18, 2026	Creation, [bit1], [gfh1], [rcj1].
1.0	Patrick Gross	June 18, 2026	First published.

This page was last updated on June 18, 2026.