Incident
at 32NM E SASKATOON / JOHN G. DIEFENBAKER INTL SK (CYXE)
A Morningstar Air Express Inc. Boeing 757-2B7 (C-FMHA/MAL7070) from Edmonton, AB (CYEG) to Winnipeg/James Armstrong Richardson, MB (CYWG) declared "PAN PAN" at FL350 due to a cabin pressure issue and requested descent to 14,000ft above sea level (ASL). The pilot reported that the situation normalized while descending through FL230 and requested to level off at FL210. MAL7070 continued to its destination with no further issues. No impact to operations.
UPDATE: TSB Report #A21C0022: C-FMHA, a Boeing 757-200 aircraft operated by Morningstar Air Express Inc., was conducting flight MAL7070 from Edmonton, AB (CYEG) to Winnipeg/James Armstrong Richardson, MB (CYWG). While cruising at FL350, the flight crew received a "Cabin Alt" master warning. The cabin altitude was noted to have risen above 10 000 feet with the outflow valve fully closed. The flight crew declared "PAN PAN", and requested a descent to 14,000 feet above sea level. As the aircraft descended through FL230, the flight crew reported normal pressurization and requested FL210. The flight continued to its destination without further incident. The aircraft was operating with an inoperative right-hand air conditioning pack that had been deferred in accordance with the minimum equipment list (MEL), which restricted operation to a maximum altitude of FL350. However, the aircraft was unable to maintain maximum cabin
differential pressure at the flight planned FL350. The next leg of flight MAL7070 was cancelled pending the replacement of the air conditioning pack and clearing the MEL item.
UPDATE: Aviation Incident Report #16999: A Morningstar Air Express Boeing 757-2B7 (C-FMHA/MAL7070) from Calgary, AB (CYYC) to Winnipeg/James Armstrong Richardson, MB (CYWG) received a master warning message "Cabin Alt" while en route between CYYC and CYWG. The cabin altitude was above 10,000 feet with the outflow valve fully closed. A "PAN PAN" was declared and the crew started to descend until a reasonable cabin altitude was reached. Upon arrival in CYWG, MAL7070 was declared "aircraft on ground" (AOG). Necessary parts for the repair were shipped on a Morningstar Air Express aircraft (MAL7079) from Toronto/Lester B. Pearson, ON (CYYZ) to Winnipeg/James Armstrong Richardson, MB (CYWG). MAL7070s second scheduled leg from Winnipeg/James Armstrong Richardson, MB (CYWG) to Toronto/Lester B. Pearson, ON (CYYZ) was cancelled. A Morningstar Air Express aircraft (MAL8079) was rerouted from Vancouver, BC (CYVR) to Toronto/Lester B. Pearson, ON (CYYZ), with an en route stop at Winnipeg/James Armstrong Richardson, MB (CYWG). A Morningstar Air Express aircraft (MAL7940) from Toronto/Lester B. Pearson, ON (CYYZ) to Winnipeg/James Armstrong Richardson, MB (CYWG), returning Toronto/Lester B. Pearson, ON (CYYZ), was set up as an ad hoc flight in order to recover the freight.