INVESTIGATION OF GROUND CREW NOISE EXPOSURE FOR THE ROYAL CANADIAN AIR FORCE CH-149 CORMORANT HELICOPTER
Bibliographic record
Abstract
Royal Canadian Air Force (RCAF) CH-149 Search and Rescue helicopter aircrew operate in dynamic operational conditions including long-duration search and rescue as well as strenuous open-door hoisting activities. During emergencies, civilians and ground crew may be exposed to aircraft noise within the cabin as well as in the external proximity of the aircraft. Due to the demanding nature of search and rescue activities, civilians, aircrew and ground crew may or may not be equipped with properly fitted hearing protection throughout a noise exposure event. The objective of the recent National Research Council (NRC) – Department of National Defence joint investigation was to characterize the noise levels of the CH-149 helicopter cabin and cockpit throughout 48 representative flight and ground conditions.This paper will outline the NRC ground external noise measurement of the CH-149 Cormorant at Comox Canadian Forces Base, January 2017. The contextual performance of the current in-service RCAF hearing protectors whilst exposed to CH-149 aircraft noise is evaluated. Overall sound pressure levels of 109.8 dB(A) were reported in the proximity of the CH-149 Cormorant throughout standard start-up procedures. It was observed that the directivity of the aircraft engine exhaust and auxiliary power unit exhaust significantly affected external sound pressure levels heterogeneously about the aircraft. In accordance with the Canadian Aviation Occupational Health and Safety Regulations, individuals exposed to aircraft external noise, without properly fitted hearing protection, could exceed their recommended cumulative maximum noise exposure dose within 2 minutes 24 seconds for a single 24 hour period. When equipped with a properly fitted SPH5-CF hearing protector, all locations exhibited significantly reduced sound pressure levels with recommended maximum noise exposure limits in excess of 16 hours, for a single 24 hour period.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.000 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".